Sonication-induced J-aggregation in nonhalogenated solvents boosts exciton delocalization for high-efficiency organic solar cells

Domain: physics
Published: 2025-11-25
Editorial outcome: minor_revision

Abstract
The commercialization of organic solar cells (OSCs) requires eliminating halogenated solvents. However, the disordered molecular aggregation of nonfullerene acceptors (NFAs) in nonhalogenated solvents hinders achieving high power conversion efficiencies (PCEs). Herein, this problem is addressed using an external physical field modulation strategy involving the sonication of NFA solutions to induce a transformation from disordered molecular aggregation to ordered J-aggregation via microstreaming and shear stress. The aggregation is effectively preserved within films, enhancing π-π stacking interactions. Moreover, sonication promotes the conversion of localized excitons to intra-moiety delocalized excitons and suppresses molecular vibrations. The PCEs of PM6:L8-BO-based binary and ternary devices fabricated using o-xylene are 19.43% and 20.41% (certified 19.84%), ranking among the highest values reported for nonhalogenated solvent-processed OSCs. The binary devices also exhibit high thermal stabilities (T80 lifetime > 10000 h). This universally applicable strategy effectively controls disordered aggregation in NFA solutions, thus paving the way for practical industrial applications.

Introduction
Owing to their intrinsic flexibility, semitransparency, and remarkable cost-effectiveness, organic solar cells (OSCs) hold promise for next-generation photovoltaic technologies1–5. Rapid advancements in material synthesis, molecular modification, and device engineering have resulted in single-junction OSCs with power conversion efficiencies (PCEs) exceeding 20%, which represents an important milestone on the road to industrial production6–10. However, these PCEs are strongly affected by spin-coating processes that rely on highly toxic halogenated solvents (such as chloroform) incompatible with large-scale production11–13. In contrast, the low solubility of numerous non-fullerene acceptors (NFAs) in ecofriendly nonhalogenated solvents leads to substantial aggregation during processing14–17, with disordered molecular orientations severely hindering exciton dissociation and charge transport. Consequently, a substantial efficiency gap exists between OSCs processed using halogenated and non-halogenated solvents18–21, which highlights the importance of controlling NFA preaggregation in nonhalogenated solvents for achieving high photovoltaic performance22–25.

The disordered aggregation state of NFAs in nonhalogenated solvents is typically transformed into more ordered H- or J-aggregation through deliberate induction to eliminate its adverse effects. Compared to H-aggregation (face-to-face stacking), J-aggregation is formed through intermolecular sliding packings, exhibiting distinctive photophysical properties in terms of expanding light absorption and enhancing charge transport26. Various approaches have been explored to induce the formation of J-aggregation to improve the PCEs of OSCs. For example, Zhang et al. optimized the π-π stacking and refined the phase separation by promoting donor J-aggregation with highly volatile additives26. Li et al. employed molecular modification to weaken the interaction between acceptor molecules and the solvent. This helps to facilitate pronounced J-aggregation, thereby enhancing charge extraction and inhibiting charge recombination27. Despite the progress enabled by these approaches, the additive- and molecular-modification-based strategies involve complex synthesis and precise chemical control28,29. These simplicity- and adaptability-related challenges hinder widespread practical applications of OSCs. External physical fields, such as heat, light, and electric stimuli, enable precise modulation of material solution state, film-formation process, and post-deposition metastable phases through straightforward processing30,31. Ultrasound emerges as a uniquely powerful tool to selectively cleave noncovalent interaction networks via physical shear effects at the molecular scale by harnessing tunable acoustic cavitation energy32,33. Concurrently, ultrasound-induced microstreaming can orchestrate molecular rearrangement, offering exceptional control over aggregation pathways. This efficient, ecofriendly approach that remains largely uncharted in organic photovoltaics hold significant potential to address the detrimental preaggregation of NFAs in non-halogenated solvents. Elucidating the physical mechanism underlying the sonication-induced regulation of NFA aggregation is therefore essential for achieving high-performance OSCs processed by non-halogenated solvents.

Herein, we use sonication to manipulate the preaggregation of NFAs in nonhalogenated solvents. The results of molecular dynamics simulations, quantum chemical computations, and multiple experiments demonstrate that sonication induces a transition from amorphous aggregation to ordered J-aggregation because of the effects of microstreaming and shear stress generated during the sonication process. Morphological studies reveal that sonication enhances intermolecular interactions in neat and blend films and thus promotes ordered molecular stacking. A global fitting model is developed to analyze transient absorption (TA) data to quantify the contributions of different charge separation (CS) pathways, and that of the pathways dominated by intra-moiety delocalized excitons is shown to markedly increase after sonication, which indicates a concomitant exciton dissociation enhancement. Sonication is also shown to inhibit molecular vibrations and thereby hinder nonradiative recombination. The binary and ternary OSCs prepared using sonication feature PCEs of 19.43 and 20.41% (certified 19.84%), respectively, along with high thermal stabilities (T80 lifetime > 10,000 h). The sonication strategy is applicable to other small-molecule and polymer acceptor systems, offering unique insights into the development of high-performance OSCs based on nonhalogenated solvents.

Results
Mechanism of sonication-regulated NFA aggregation
Figure 1a shows the chemical structures of the donor (PM6) and acceptor (L8-BO), and illustrates the sonication-assisted film fabrication processes based on the sequential deposition of these species. Initially, a PM6 layer is constructed on an indium tin oxide (ITO) substrate, and a sonicated solution of L8-BO in o-xylene (o-XY) is deposited onto the PM6 layer. For numerous organic materials, amorphous aggregate formation due to nanoscale precipitation is observed in low-solubility solvents (such as o-XY), unlike in the case of high-solubility solvents (such as chloroform)34. This problem is solved by using ultrasound filed. Sonication causes cavitation, i.e., the formation of tiny bubbles that can rapidly grow and collapse under the periodic pressure changes caused by ultrasonic waves35 (Supplementary Fig. 1). The cavitation effect could alter molecular aggregation states via microstreaming and shear stress. We performed in-situ photoluminescence (PL) spectroscopy measurements of L8-BO solution (o-XY) to monitor the change in aggregation state during sonication (Fig. 1b and Supplementary Figs. 2–5). Combined with device data (which will be discussed subsequently), the optimal sonication condition was identified at 40 kHz, 720 W and 3 mins, as detailed in the Supplementary Information. However, sonication is typically accompanied by physical and chemical effects36,37. In order to rule out the destructive on the material structure from chemical effects, we tested the Raman spectra of L8-BO solution before and after sonication, as shown in Supplementary Fig. 9. The unaltered peak positions after sonication suggest that no chemical reaction have occurred, but only physical effects exist.

Upon sonication, the emission peak of L8-BO shifted to substantially longer wavelengths, moving from 793 to 805 nm within three minutes (Fig. 1b), which indicated a concomitant increase in the extent of solution-phase J-aggregation38. Notably, J-aggregation was well maintained in the solution with in ten days after sonication was stopped (Supplementary Fig. 10), which was sufficient for spin-coating preparation of films and industrial production. Molecular dynamics simulations (see detail in Supplementary Information) were used to verify the effects of sonication on L8-BO molecules dissolved in o-XY (Fig. 1c). Without sonication (in the control system), the L8-BO molecules formed a dispersed state, with the radius of gyration (Rg) and solvent-accessible surface area (SASA) fluctuating around their mean values. Conversely, in the case of sonication, the Rg and SASA values notably decreased before stabilizing, suggesting that sonication increased the degree of aggregation (Fig. 1d and Supplementary Fig. 11). Root mean square deviations (RMSDs) were calculated to observe the overall conformational changes relative to the initial structure throughout the simulation period (Fig. 1e). In both systems, the RMSD initially increased before reaching equilibrium, which reflected rapid convergence toward a stable equilibrium state. The local magnification of simulation snapshots revealed that the control system contained some amorphous structures and H-aggregates, while a marked increase in the number of J-aggregates was observed after sonication, in line with the in-situ PL spectroscopy results.

Quantum chemical computations were performed to clarify the mechanisms underlying the sonication-induced J-aggregation (Supplementary Figs. 12a, b). An extended version of the Su–Schrieffer–Heeger tight-binding model was utilized, with a comprehensive description of the calculation process provided in the Supplementary Information39. J-aggregation can be categorized into A-to-A and A-to-D types. Supplementary Fig. 12c shows the band gaps of different aggregation modes. The red shift of the PL spectrum is consistent with a reduction in band gap, suggesting a transformation into the A-to-D type J-aggregation. Hence, we focused exclusively on this type of J-aggregation in subsequent analyses. The results (Supplementary Figs. 12d, e) indicated that under various conditions, the aggregation energy of J-aggregation consistently exceeded that of H-aggregation, i.e., the latter aggregation was energetically preferred40. Hence, NFAs tended to form H-aggregates in the absence of sonication. Cavitation bubbles are generated during the sonication process. As depicted in Supplementary Fig. 13, the periodic contraction and expansion of cavitation bubbles create a marked velocity gradient between the bubble surface and the surrounding solvent. This gradient drives the generation of microstreaming and shear stress (a pair of parallel reaction forces)41. Microstreaming pushes L8-BO molecules to aggregate on the bubble surface. Then the disordered molecules will be oriented and arranged under the effect of shear stress42, and subsequently become ordered J-aggregation. Meanwhile, the H-aggregation can overcome the energy barrier after acquiring energy and sliding to ordered J-aggregation.

The aggregation behavior of sonicated L8-BO in o-XY was investigated using temperature-dependent PL spectroscopy (Fig. 1f and Supplementary Fig. 14). The long-wavelength shoulder peak (855 nm) / main peak (805 nm) intensity ratio (I0-1/I0-0) obtained through the double-peak fitting analysis of the PL spectra was employed to quantify the effects of sonication on the aggregation state at different temperatures (Fig. 1g and Supplementary Table 1)43. Sonicated L8-BO exhibited more pronounced I0-1/I0-0 variations, along with a stronger dependence of this ratio on the solution temperature compared with the untreated sample, which manifested the enhanced intermolecular interactions and an increased tendency for aggregation. As mentioned above, J-aggregation was well maintained in the solution phase, further influencing the film morphology. Subsequently, we analyzed the ultraviolet (UV)–visible absorption and PL spectra of the corresponding films (Supplementary Figs. 15 and 16). Sonication induced red shifts in the absorption and PL peaks of the L8-BO film, while predictably enhancing its crystallinity44. This effect was quantitatively assessed using grazing-incidence wide-angle X-ray scattering (GIWAXS) measurements (Fig. 1h and i, Supplementary Fig. 17, and Supplementary Table 2). Prominent π-π stacking peaks of the control (1.753 Å) and sonicated (1.769 Å) L8-BO films were observed in the out-of-plane (OOP) direction45. The decrease in d-spacing from 3.584 to 3.552 Å after sonication indicated a closer intermolecular packing. The calculated crystal coherence length (CCL) increased from 23.46 Å in the control film to 25.13 Å in the sonicated film. Thus, the sonicated L8-BO film exhibited a higher crystallinity and more ordered molecular stacking than its nonsonicated counterpart. Time-resolved photoluminescence (TRPL) measurements revealed that sonication increased the exciton lifetime of the L8-BO film from 471 to 641 ps, possibly by favoring ordered J-aggregation46.

Blend film morphology
Sonicated L8-BO was combined with PM6 via sequential deposition to construct layer-by-layer (LBL)-type devices and thus assess the role of sonication in determining blend film morphology. According to the corresponding two-dimensional (2D) GIWAXS patterns (Fig. 2a, b), both PM6 and L8-BO exhibited a preferential face-on orientation in blend films, which favored charge transport, as evidenced by prominent (100) lamellar stacking peaks in the in-plane (IP) direction and strong (010) π-π stacking peaks in the OOP direction. After sonication, the CCL of the blend films increased from 24.48 to 27.32 Å, and the d-spacing decreased from 3.588 to 3.550 Å (Fig. 2c and Supplementary Table 3). These results suggested that sonication facilitated crystallization and ordered molecular stacking within the active layers. Grazing-incidence small-angle X-ray scattering (GISAXS) measurements were performed to characterize the donor and acceptor domain sizes in the blend films and thus investigate phase separation behavior at the nanoscale (Supplementary Fig. 12). The Debye–Anderson–Brumberger and fractal models were used for fitting47. The relevant fitting steps are presented in the Supplementary Information, and the relevant fitting parameters are summarized in Supplementary Table 4, with ζ, η, D, and 2Rg representing the average correlation length of the PM6 phase, correlation length, fractal dimension of L8-BO clusters, and size of clustered L8-BO domains, respectively. After sonication, the 2Rg value of the blend films increased, indicating the expansion of acceptor-enriched domains, which facilitated the formation of an optimized morphology and suitable phase separation.

To further elucidate the potential mechanisms underlying the effect of sonication on active layer growth, we conducted in-situ UV–visible absorption spectroscopy to monitor the film-formation process of the PM6:L8-BO blends. The characteristic peaks of PM6 and L8-BO were observed within the ranges of 400–660 nm and 660–950 nm, respectively (Supplementary Fig. 19), and peak position changes were analyzed (Fig. 2d, e). Based on peak evolution, the film-formation process was divided into three stages: (i) solvent evaporation and crystal nucleation, (ii) crystallization, and (iii) film formation48. Ordered aggregation in the sonicated L8-BO solution allowed the first stage to begin earlier, thus benefiting the prolonged molecular stacking in the second stage. The red shift of the L8-BO molecular peaks after the film-formation stage further corroborates the formation of J-aggregates. Additionally, during the film-formation process of L8-BO, the peak position of PM6 exhibited a notable blue shift, which was attributed to the immediate deposition of the L8-BO layer. The swelling effect resulted in the dissolution of a part of the donor layer during acceptor deposition, thus inducing additional mutual diffusion between them. Importantly, the ordered J-aggregation of the L8-BO molecules markedly reduced the secondary film-formation time of the PM6 molecules, thus minimizing the diffusion from the acceptor layer into the donor layer and thereby hindering unnecessary mixing.

The effects of sonication on the surface morphology of thin films were probed by atomic force microscopy49. Both the neat L8-BO and blend films exhibited increased root mean square (RMS) roughness values after sonication (Supplementary Fig. 20). The more refined fibril network structure in the blend films facilitated the formation of high-speed pathways for electron and hole transport. To distinguish donor and acceptor domains, the stretching of characteristic bonds was analyzed using photoinduced force microscopy (PiFM) (Supplementary Figs. 21–22, Fig. 2f, g). The line profiles extracted from the corresponding localized near-infrared images are presented in Fig. 2h, i. After sonication, the acceptor domains in the blend films exhibited fibrillar structures with an approximate diameter of 23 nm. The increase in the amount of small fibril structures indicated the formation of a fibril network between the donor and acceptor phases. The overlaid PiFM images of PM6 and L8-BO were used to further explore the sizes of the different phases (Supplementary Figs. 23)50, revealing that sonication prevented excessive donor–acceptor mixing. This is beneficial for reducing geminate recombination and increasing the fill factor (FF), which will be discussed below.

Film-depth-dependent light absorption spectroscopy was conducted to analyze the effects of sonication on the vertical phase separation of the thin films (Supplementary Fig. 24)51. Sonication increased the acceptor concentration near the cathode, resulting in an optimized vertical gradient distribution within the blend films (Fig. 2j). This optimization was conducive to the rapid transfer of excitons to the acceptor phase after dissociation. The effects of sonication on the morphological evolution of the L8-BO molecular aggregates were rationalized as follows (Fig. 2k). Without sonication, the L8-BO molecules spontaneously formed H-type and amorphous aggregates in the solution. This disordered aggregation contributed to an irregular distribution within the solid film and adversely affected charge transfer (CT). Conversely, upon sonication, the L8-BO molecules formed ordered J-type aggregation in the solution. This preconstructed ordered aggregation was effectively retained during subsequent crystal growth stages, which promoted ordered molecular stacking and considerably enhanced π-π stacking interactions among molecules. Meanwhile, the sonication strategy optimized the phase separation of blend films and facilitated the formation of a fibril network. This sonication-induced morphological optimization can be expected to improve exciton and charge behaviors.

TA analysis of exciton delocalization
Femtosecond TA spectroscopy measurements were performed to probe the impact of the sonication-optimized microstructure on exciton and charge dynamics. The L8-BO acceptor was selectively excited at 800 nm. The 2D colormaps of the TA spectra of the blend films produced from non- and sonicated solutions are presented in Fig. 3a and Supplementary Fig. 25a. The ground-state bleaching (GSB) signal of the PM6 donor at 580 nm was extracted and analyzed using exponential fitting to track hole transfer kinetics (Supplementary Fig. 26a and Supplementary Table 5)52. The decrease in lifetime of the sonicated films from 0.34 to 0.24 ps indicates a concomitant increase in the rate of hole transfer53. The signal of the localized exciton (LE) state of the acceptor was extracted at 880 nm (Supplementary Fig. 26b). Sonication-induced morphology tuning considerably accelerated excited state decay (i.e., the lifetime decreased from 3.89 to 2.28 ps) and thus increased the efficiency of exciton dissociation (Supplementary Table 6)54. In addition, the extended lifetime of the polaron signals observed at 960 nm revealed that bimolecular recombination was suppressed in the sonicated film31 (Supplementary Fig. 26c). Supplementary Fig. 26d showed the kinetic curves of the intra-moiety delocalized excitons (i-DE) extracted from TA spectra at 1500 nm55. This signal was related to the exciton delocalization and will be discussed in detail below.

Global fitting was used to explore the effects of sonication on the contributions of different exciton dissociation pathways (Fig. 3b). The CS process is governed by competition between the LE→i-DE→CS and LE→CT→CS pathways. The former pathway involves a rapid (within ~0.2 ps) transformation of LE states into i-DE states in the acceptor domain owing to strong intermolecular interactions among conjugated units. The i-DE states subsequently transform to CS states55. The latter pathway resembles traditional models, with LE states diffusing to the donor/acceptor (D/A) interface, transforming to CT states, and further dissociating into CS states. TA spectra recorded using different time delays were analyzed to extract the dynamic evolution signals corresponding to the LE, i-DE, CT, and CS states (Fig. 3c–f and Supplementary Figs. 25b–e), with the associated contributions shown in Fig. 3g. For both the control and the sonicated samples, the transient spectral features evolved on similar timescales. Under 1 ps, GSB features matching the steady-state absorption spectrum of the blend film were prominent in the visible region between 550 nm and 780 nm. A positive excited-state absorption (ESA) feature between 450 nm and 550 nm corresponding to the extracted spectrum of the i-DE states suggested the ultrafast formation of this state within the coherence time (~200 fs). This ESA returns to a negative GSB after tens of ps, indicating a progression of the system from the i-DE states to new intermediates (CT/CS). On the timescale of tens of hundreds of ps, whilst the GSB features were still present, the transient spectra adopt broad ESA features spanning from 650 to 1500 nm. This is similar to the CT/CS state ESA spectral features observed in PM6/Y6 systems55. The spectrum of the CS state was similar to that of the CT state but with a more flattened ESA feature extending into the NIR region with an absence of a positive peak at ~660 nm. On a ~200 fs timescale, the sharp ESA of the LE state in the NIR region around 850 nm developed a more prominent shoulder around 960 nm, indicating the ultrafast formation of polarons upon formation of the CT state. The intensity of the NIR signal from 1000 to 1500 nm decayed much more slowly compared to the signal at 850–900 nm in the first 10 ps, and through global analysis, this signal was mainly attributed to the LE and the CT states.

After sonication, the contribution of the pathway dominated by i-DE states substantially increased (0.54→0.6), which indicated that the resulting morphology in the sonicated films facilitate exciton delocalization. It can effectively reduce the dependence of exciton dissociation on the D/A interface55–57. Figure 3h shows the fitted lifetime for each stage of the two pathways. The lifetime for all three stages after sonication (τ1 = 0.23 ps, τ2 = 2.99 ps, τ3 = 156 ps) were notably shorter than those observed in the control system (τ1 = 0.36 ps, τ2 = 6.11 ps, τ3 = 248 ps). Accordingly, the rates of evolution towards successive states in the sonicated film (k1 = 4.35 ps−1, k2 = 0.33 ps−1, k3 = 0.0064 ps−1) were faster than that in the control film (k1 = 2.78 ps−1, k2 = 0.16 ps−1, k3 = 0.0040 ps−1). These results suggested that the sonication strategy promoted efficient exciton dissociation in both pathways. In addition, the lifetime of the CS state markedly increased after sonication (from 8.6 to 10.6 ns), which indicated suppressed charge recombination.

Exciton diffusion length (LD) plays a crucial role in the CS pathway dominated by the CT state. To investigate the influence of sonication on LD, we recorded the pump-fluence-dependent TA spectra of the L8-BO neat films (Supplementary Fig. 26e, f)51, revealing that the exciton decay rate increased with increasing excitation intensity. Two primary quenching pathways were considered, characterized by the intrinsic exciton decay rate coefficients (k) at any given excitation flux and bimolecular decay rate coefficients (γ) for exciton–exciton annihilation at high pump fluences54. The following diffusion equation was used to globally fit the TA decay curves of the L8-BO acceptor:

dn(t) / dt = -kn(t) - 1/2 γn^2(t) (1)

Based on this equation, we derived a function describing the variation in singlet exciton density distribution n with time t:

n(t) = n(0)e^-kt / (1 + γn(0) / 2k * (1 - e^-kt)) (2)

where γ = 8πRD (D is the exciton diffusion coefficient, and R is the annihilation radius of the singlet excitons (assumed to equal 1 nm)). The fitted parameters are listed in Supplementary Table 7. The exciton diffusion length LD = sqrt(Dτ) increased from 29.66 to 36.56 nm after sonication (Fig. 3i), indicating efficient exciton transport to the D/A interface and supporting the subsequent conversion to CT states. This agrees with the efficient CT suggested by the global fitting results, which is an essential prerequisite for achieving high-efficiency OSCs58.

Molecular vibration and nonradiative recombination
Based on the aforementioned insights into exciton and charge dynamics, transient infrared (TRIR) spectroscopy was used to further examine the effects of the optimized morphology induced by sonication on molecular vibration (Fig. 4a, Supplementary Figs. 27a–c). We extracted the polaron dynamic curve within the 1700–1800 cm−1 range, where the contributions from molecular vibrations were minimal (Fig. 4b). The blend films prepared using sonicated solutions demonstrated accelerated charge generation (i.e., the polaron signal rise time decreased from 9.17 to 6.64 ps) and slightly slowed charge recombination, in line with the TAS results. To analyze the transient vibrational spectra and dynamic changes precisely, we used a cubic polynomial function to fit the polaron background and deconvolute its contributions (Supplementary Fig. 28), as illustrated in Fig. 4c and Supplementary Fig. 27d59. According to the FTIR spectra (Supplementary Fig. 21), the double-peak GSB absorption feature between 1500 and 1550 cm−1 corresponds to L8-BO vibration (C=C bond in ring). These features were sharp at early times and broaden after 10s of ps. The derivative-type feature with a positive peak at 1485 cm−1 (~10 cm−1 downshift from the main absorption peak) can most likely be attributed to hot ground states (S0) or hot LE (with minimal structural distortion from the S0).

This derivative signal decayed more rapidly in the sonicated sample (8.3 ps) compared to the control blend (10.7 ps, Fig. 4d) and was likely due to the faster heat dissipation in more structurally ordered molecular solids which allowed efficient propagation of phonons. Another noticeable difference was the vibrational peak widths in the TRIR spectra. Figure 4e compares the GSB feature around 1533 cm−1 at 850 ps for the control and the sonicated blend. The peak widths of the control were broader than the sonicated blend, hinting to the existence of a wider variety of relative molecular orientations, thus, a greater degree of disorder. Therefore, it was evident that the structural tuning via sonication successfully reduced the disorder in the film, allowing for efficient propagation of both thermal energy and charge. This result is further discussed with TRPL experimental results in a later section.

The removal of the polaron background allowed us to isolate the vibrational mode of PM6 at 1649 cm−1 (see FTIR spectra in Supplementary Fig. 21a). The recovery of this GSB feature was faster in the sonicated blend (5.84 ps), whereas for the control blend (7.13 ps), a small ESA signal at 1670 cm−1 slowly emerged after 10s of ps. This subtle difference suggested that when CT/CS states formed, in the more structurally ordered sonicated film, the PM6 did not undergo much geometry change. However, in the control film, the PM6 was structurally disturbed in the CT/CS states, inducing a frequency shift. Another subtle difference was at 1750 cm−1. In the control film, an ESA feature was observed after the pulse duration ~300 fs and slowly recovered during the scan window. In the sonicated film, this ESA decayed into a clear bleach signal after several hundreds of ps. The FTIR of the sonicated L8-BO neat film compared to the untreated L8-BO hinted that this vibrational mode was likely associated with the presence of J-aggregated L8-BO (π-π stacked geometry). Given that the enhancement of this signal appeared at early times in both films, a possible explanation can be the formation of i-DE states within ~200 fs enhanced neighboring L8-BO coupling through π−π stacking.

Temperature-dependent PL and TRPL spectra were recorded to further evaluate the effects of sonication on exciton–vibration coupling and thermally activated processes. With increasing temperature, the PL spectra shifted to shorter wavelengths and broadened (Supplementary Fig. 29). The interactions between excitons and molecular vibrations can be inferred from the peak positions60, which are quantitatively described by:

E(T) = E(0) - 2α / (exp(θ/T) - 1) (3)

where E(0) is the bandgap energy at absolute zero (0 K), α is the intensity of the exciton–vibration interaction, and θ is the average phonon temperature. The sonicated films demonstrated reduced α from 151.2 to 113.3 meV (Fig. 4g and Supplementary Table 8) and was therefore concluded to inhibit exciton–vibration coupling and promote exciton diffusion and polaron transport. By fitting a series of temperature-dependent TRPL spectra (Supplementary Fig. 30), we obtained the temperature dependence of the nonradiative recombination rate, Knr (Fig. 4h). In high-temperature regions, Knr was more sensitive to temperature changes than in low-temperature regions because of the increase in molecular vibrations induced by thermal energy61. Moreover, a thermally activated process occurred between the S0 and excited states (S1)62 (Fig. 4i). Molecular vibrations led to the formation of an overlapping surface between S0 and S1, which introduced an additional pathway for internal conversion processes63. As discussed previously, sonication-induced structural tuning with ordered J-aggregate geometry allows for rapid thermal energy redistribution and dissipation61, which deactivates the thermally-activated non-radiativerecombination of excitons.

Photovoltaic characteristics
To substantiate the benefits of the ordered J-aggregation induced by sonication, we fabricated LBL-type OSCs with an ITO/PEDOT:PSS/active layer/PDINN/Ag structure and tested the device performance under different sonication frequencies, power and duration (Supplementary Figs. 31–33 and Supplementary Tables 9–15). Details on the preparation and optimization are provided in the Supplementary Information. The J–V curves and photovoltaic parameters of the optimized devices are presented in Fig. 5a and Table 1. The control device achieved a PCE of 17.50%, an open-circuit voltage (VOC) of 0.878 V, a short-circuit current (JSC) of 25.36 mA cm−2, and a FF of 78.56%, in agreement with previously published results64,65. By controlling the sonication condition, we achieved a notably increased PCE of 19.43%, a VOC of 0.881 V, a JSC of 27.05 mA cm−2, and a FF of 81.53%. Compared with that of the control, the external quantum efficiency (EQE) spectrum of the sonication-processed device was shifted to longer wavelengths. Similar to internal quantum efficiency (IQE), it also exhibited a higher full-spectrum response (Fig. 5b and Supplementary Fig. 34), as evidenced by more efficient exciton dissociation and charge extraction (Supplementary Fig. 35 and Supplementary Table 20). Subsequently, we fabricated ternary PM6:D18:L8-BO devices with different active layer thicknesses. The device with a 100 nm-thick active layer featured an increased PCE of 20.41% (certified as 19.84% by the National Institute of Metrology, China) (Fig. 5c and Supplementary Fig. 36), a VOC of 0.899 V, a JSC of 27.43 mA cm−2, and a FF of 81.19%; this PCE is one of the highest values reported for OSCs prepared using nonhalogenated solvents (Fig. 5d, Supplementary Tables 21 and 22). The 300 nm-thick device demonstrated a satisfactory PCE of 18.29%, with the FF (76.19%) ranking among the top values reported for an active layer thickness of 300 nm. The corresponding EQE spectra are presented in Supplementary Fig. 37. All JSC values extracted from the J–V curves differed from the integrated current density of the EQE by <5%, thereby confirming the reliability of the photovoltaic performance.

To explore the potential of the sonication strategy for scalable industrial application, we fabricated flexible devices (1 cm2) using the roll-to-roll technique in air. The devices were fabricated using an inverted structure of PET/Ag-grid/PH1000/ZnO/active layer/MoOx/Ag. The detailed fabrication process is presented in the Supplementary Information. The J-V curves and device parameters are shown in Supplementary Fig. 38 and Supplementary Table 23. The control devices exhibited a PCE of 12.06%, a VOC of 0.826 V, a JSC of 21.71 mA cm−2, and a FF of 67.28%. After sonication, the device performance was improved, with a PCE of 14.04%, a VOC of 0.828 V, a JSC of 23.89 mA cm−2, and a FF of 71.00%. The corresponding EQE spectra are shown in Supplementary Fig. 38b, with the integration current error controlled within 5%. The significant improvement in device performance indicates that the sonication strategy is also effective for devices prepared by the roll-to-roll technique, which holds critical implication for their industrial production.

The space charge limited current method was used to evaluate the charge transport which is related to the FF between the devices prepared under control and sonication conditions (Supplementary Fig. 39). The calculated hole and electron mobilities are presented in Fig. 5e and Supplementary Table 24. Sonication increased hole mobility (μh) from 6.27 × 10−4 cm2 V−1 s−1 to 8.59 × 10−4 cm2 V−1 s−1 and electron mobility (μe) from 5.43 × 10−4 cm2 V−1 s−1 to 8.19 × 10−4 cm2 V−1 s−1. The higher mobility and lower μh/μe ratio observed for the devices prepared under sonication conditions indicated more efficient and balanced charge transport45. The density of trap states (Nt) was calculated using frequency-dependent capacitance spectra recorded under dark conditions (Fig. 5f). The decrease in Nt from 2.02 × 1016 cm−3 eV−1 to 0.98 × 1016 cm−3 eV−1 indicated that sonication effectively prevented trap state generation66. The relationship between JSC and light intensity (Plight) was fitted as JSC = (Plight)α (Supplementary Fig. 40a). Sonication increased α from 0.988 to 0.994 and thus effectively inhibited bimolecular recombination processes67. The lower slope of the VOC–ln(Plight) plot observed for the sonicated film (Fig. 5g) signified the suppression of trap-assisted recombination, thereby enhancing charge transport in the OSCs68. The increase in carrier lifetime from 5.83 to 7.44 μs revealed by transient photovoltage (TPV) tests supported this observation (Supplementary Figs. 40b–c). Transient photocurrent (TPC) tests revealed accelerated charge extraction (i.e., fitting lifetime decreased from 0.35 to 0.26 μs) in the devices prepared under sonication conditions. Energy loss was evaluated based on the measurements of the electroluminescence (EL) spectra, the external quantum efficiency of electroluminescence (EQEEL), and the sensitive external quantum efficiency (sEQE) measured by Fourier transform photocurrent spectroscopy (FTPS-EQE) (Supplementary Fig. 41 and Supplementary Table. 26). It was concluded that sonication slightly suppressed the energy loss, especially non-radiative recombination loss ΔE3 (from 0.243 to 0.239 eV). Meanwhile, the extracted Urbach energy decreased from 24.16 to 23.57 meV, suggesting a concomitant reduction in energy disorder69, which is aligned with the decrease of radiative recombination loss ΔE2 (from 0.076 eV to 0.074 eV). These results confirm that sonication can be used to improve OSC performance.

Given that sonication can improve OSC efficiency, one can reasonably anticipate that it may also increase device stability. To minimize the adverse impact of organic interfacial layers on stability, we fabricated inverted devices with an ITO/ZnO/active layer/MoO3/Ag configuration. Thermal stability was assessed upon continuous annealing in dry nitrogen atmosphere at 80°C (Fig. 5h). Compared with the control devices, the sonication-processed devices (ten independent cells) exhibited a markedly reduced burn-in loss and an improved thermal stability. PCE decay was subjected to linear fitting, and the results indicated that the T80 lifetime of the optimized devices markedly exceeded 10000 h. We also tested the photothermal stability of OSCs under continuous illumination at 100 mW cm−2 (50°C–60°C), revealing that sonication also increased resistance to photothermal stress (Fig. 5i).

To elucidate the mechanism by which sonication improved morphological stability, we extracted the normalized photovoltaic parameters (VOC, JSC and FF) over aging time for PM6:L8-BO-based devices, as shown in Supplementary Fig. 42. The control devices remained relatively stable VOC and JSC, whereas FF showed a marked decline. In contrast, the sonicated devices exhibited robust FF, indicating that sonication could suppress the degradation in mixed amorphous regions70,71. Additionally, the sonicated films showed slight attenuation of CCL values (from 27.32 to 26.93 Å) after continuous thermal aging for 200 h compared to that (from 24.48 to 23.08 Å) of controls (Supplementary Fig. 43 and Supplementary Table. 27), suggesting the better stability in crystalline regions. Further thermodynamic analysis was conducted on neat L8-BO films and PM6:L8-BO blend films through the glass transition temperature (Tg) measurements (Supplementary Figs. 44 and 45). The sonicated samples displayed higher Tg than the controls, indicating that sonication reduced the diffusion coefficient of material in mixed amorphous region and enhanced the kinetic stabilization of film morphology9,72. The results demonstrate the advantages of the sonication-improved active layer morphology for improving device stability.

Application scope of the sonication strategy
To explore the application scope of the ultrasound-field-based regulation of ordered J-aggregation in NFAs, we recorded the in-situ PL spectra of other PM6:NFA systems, including BTP-eC9, PY-IT, and PY-DT, during the sonication process (Fig. 6a–c). In addition to the continuous red shift of the PL spectra, we observed the continuous intensification of the long-wavelength shoulder peaks of the PY-IT and PY-DT polymer acceptors, which suggested a concomitant increase in the extent of J-aggregation. We also recorded the temperature-dependent PL spectra of these systems (Supplementary Fig. 47) and extracted the corresponding I0-1/I0-0 peak intensity ratios (Fig. 6d–f and Supplementary Table 28). The results showed enhanced temperature dependence, indicating intermolecular interaction and aggregation enhancement. Subsequently, solar cells based on these three systems were fabricated using a conventional device structure (Supplementary Fig. 48). The corresponding J–V curves are shown in Fig. 6g–i, and the device parameters are summarized in Supplementary Table 29. The sonication-processed PM6:BTP-eC9, PM6:PY-IT, and PM6:PY-DT devices achieved improved PCEs of 19.31, 18.32, and 18.71% compared to control systems, respectively. These results demonstrate the broad application scope of the sonication strategy.

Discussion
The NFA aggregation state in a nonhalogenated solvent was modulated using sonication. The combined results of simulations, computations, and experiments demonstrate that sonication induced the formation of ordered J-aggregates within the NFA solutions and films through microstreaming and shear stress. Morphological characterizations revealed that sonication improved phase separation during film formation, enhancing π-π stacking interactions and optimizing the molecular arrangement. The global fitting of TA data indicated that sonication increased the proportion of CS pathways dominated by i-DE states, thereby enhancing exciton dissociation. TRIR data showed the structural tuning effect on heat and carrier transport in the system, and together with temperature-dependent TRPL data further validated the inhibitory effect of sonication on nonradiative recombination. The PM6:L8-BO devices exhibited a high PCE of 19.43% and superior thermal stability (T80 lifetime > 10000 h). The addition of D18 to the PM6:L8-BO system resulted in a remarkable PCE of 20.41% (certified PCE of 19.84%), which is among the highest efficiencies reported for OSCs prepared using nonhalogenated solvents. The developed sonication strategy was demonstrated to have a broad application scope, as exemplified by its applicability to small-molecule and polymer acceptor systems. Thus, our work provides a practical approach to the fabrication of efficient, stable, and ecofriendly OSCs, facilitating their large-scale industrial production.

Methods
Measurements of PL and TRPL spectra
The PL spectra and TRPL experiments were performed using a confocal optical microscope, specifically the Nanofinder FLEX2 from Tokyo Instruments, Inc. This setup was equipped with a time-correlated single-photon counting (TCSPC) module, the Becker & Hickl SPC-150. For all PL spectrum measurements, a charge-coupled device (CCD) sensor, model DU420A-OE from Andor, was utilized. The excitation wavelength was consistently set at 400 nm, and the excitation power for both PL spectra and TRPL experiments was maintained at 1 μW. The laser spot had an approximate diameter of 8 μm, resulting in an area calculated as S = 5.02 × 10⁻⁷ cm².

Measurements of AFM and PiFM Images
AFM measurements were performed on a Bioscope Resolve AFM (Bruker) in a tapping mode under ambient conditions. Photo-induced Force Microscopy (PiFM) measurements were performed by employing Anfatec Instruments AG (Oelsnitz, Germany).

Measurement of TA spectra
Femtosecond TA spectra were recorded using an optical setup that incorporated a Ti:sapphire femtosecond laser (from Coherent) in conjunction with an optical parametric amplifier (OPA) system. The 800 nm pulse emitted by the laser was divided into two beams via a beamsplitter. One of these beams was directed into the optical parametric amplifier (TOPAS, Coherent) to generate pump pulses at 600 nm. The second beam was focused onto both sapphire and YAG plates to produce a white light supercontinuum, which served as the probe beams with a spectral range of 750-1600 nm. The initial pulses were also split into two paths; one path led to the OPA for generating 400 and 750 nm pump pulses utilized in this study, while the other path produced a broad spectrum of probe light spanning from 520–800 nm (visible) and from 850–1300 nm (NIR).

Measurement of TRIR spectra
TRIR spectra were acquired using pump and probe beams generated through nonlinear optical processes utilizing the 1030 nm fundamental output from a Ytterbium-based laser oscillator (Pharos, Light Conversion). An optical parametric amplifier (OPA, Orpheus, Light Conversion), in conjunction with difference frequency generation (DFG, Lyra, Light Conversion), produced pump pulses with highly tunable wavelengths across the UV-NIR spectrum (210–2660 nm, ~150 fs temporal FWHM, ~5 nm bandwidth), operating at a base repetition rate of 100 kHz. The laser output was pulse picked to 10 kHz and a mechanical chopper (Thorlabs, MC1F60) was employed to reduce the pump repetition rate to 5 kHz while maintaining a probe rate of 10 kHz. The pump beam traversed a mechanical delay stage (Newport ESP300) to achieve optical delay times ranging from -50 to 900 ps and was subsequently focused to attain an approximate spatial diameter of FWHM ~420 μm at the sample location. Linear polarization devices were utilized to control the relative polarization between the pump and probe beams at the magic angle. The mid-infrared probe spanning wavelengths from 4000 to 13000 nm with a temporal FWHM of less than 180 fs, was generated by an OPA and DFG system (ORPHEUS TWINS, Light Conversion). Given that atmospheric moisture and particulate matter significantly absorb mid-infrared radiation, all components of the probe pathway were enclosed under nitrogen within sealed boxes and conduits. TRIR spectra were captured using a polychromator-based IR spectrometer cooled with liquid nitrogen during experiments (Horiba iHR320 integrated with an FPAS 128-element MCT detector; Infrared Systems; spectral acquisition rate: 10 kHz; bandwidth: ∼300 cm⁻¹). The sample was affixed to an X-Z translation stage controlled by two stepper motors for raster scanning purposes.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "The manuscript describes an ultrasound-assisted, non-halogenated processing route that converts disordered aggregates of Y-series non-fullerene acceptors into ordered J-aggregates, as evidenced by in-situ photoluminescence, molecular-dynamics (MD) simulations, and quantum-chemical calculations. Spin-coated films derived from the sonicated ink exhibit markedly improved morphology, enabling PM6:L8-BO binary cells to reach a power-conversion efficiency (PCE) of 19.43 %, while ternary cells exceed 20 % (certified 19.84 %). Devices retain 80 % of their initial efficiency for >10 000 h at 80 °C, and the strategy appears transferrable to other Y-series acceptors. Although technically sound, the work lacks the novelty and depth expected for publication in Nature Communications.\nSpecific comments are as follows:\n1. The advantages in terms of industrial feasibility and cost-effectiveness have not been fully demonstrated. In recent years, numerous studies have reported non-halogenated-solvent-processed organic solar cells with PCEs above 20%. For example, Professor Liu Feng’s group achieved over 20% PCE using a dual-additive strategy in non-halogenated solvents (Adv. Mater. 2025, 2501812) and demonstrated high efficiency in large-area modules. Moreover, Professor Wang Tao’s team showed that a simple additive enabled L8-BO devices processed in o-xylene to reach 19% efficiency (Adv. Mater. 2023, 35, 2208211). Compared with these works, although the authors obtain similar results, their manuscript does not meet Nature Communications’ standards for novelty and breakthrough. More importantly, unlike the additive approach, the simplicity, cost, and scalability of ultrasonic processing—particularly for roll-to-roll fabrication—require careful and in-depth evaluation.\n2. From the authors’ optimization data, the ultrasound-assisted process appears to operate within a very narrow window, which could hinder its broader adoption. Ultrasonic treatment requires tight control over 3 parameters (frequency, power, duration) and Supplementary Tables 9 and 10 shows that small changes in any one of these can dramatically affect device performance. For example, at 40 kHz and 720 W, a 3-minute treatment yields a PCE of ~19.5%, while extending to 4 minutes drops it to ~18.5%. Such sensitivity undermines the method’s industrial viability. I therefore recommend that the authors provide a more detailed, quantitative analysis of how each of the parameters influences J-aggregate formation.\n3. More data on solution stability after sonication are needed. It is crucial to know how long the sonication-induced aggregation persists, yet the authors only report results at 1 mins post-treatment, which is insufficient to demonstrate the durability of the induced structure. I recommend extending the observation period to several hours or even days to track the evolution of the aggregation state over time. At the same time, a thermodynamic analysis of the J-aggregate stability mechanism should be included.\n4. The details of the molecular dynamic simulations are incomplete. The authors use MD to explore how the ultrasonic field influences acceptor aggregation, but it is unclear how they modeled the ultrasonic field, how cavitation effects were introduced, and how the acceptor molecules reassemble under cavitation. I recommend that the authors provide a more detailed description of their MD methodology, including the force fields, solvent models, simulation parameters, and any specific procedures used to simulate ultrasound and cavitation.\n5. In materials research, when molecular solubility is limited, it is common to either raise the solution temperature or apply ultrasonication. The authors should clarify how the aggregation state produced by sonication differs from that obtained by simple heating. Furthermore, because sonication often induces a temperature rise, the authors need to monitor the solution temperature during ultrasonic treatment and distinguish the intrinsic mechanical effects of ultrasound from any thermal contributions.\n6. The manuscript’s presentation is confusing. A large portion of the text is devoted to charge‐transport and recombination kinetics (like TA, TRIR), yet these improvements actually stem from morphology changes induced by sonication rather than any direct effect of ultrasound on charge behavior. The repeated use of terms such as “sonication-induced lifetime”, “sonication facilitated exciton delocalization”, only adds to the confusion. If the authors wish to claim a direct impact of sonication on exciton delocalization, they should include a side‐by‐side comparison with other morphology‐control methods (for example, additive strategies). I therefore recommend streamlining the charge‐kinetics discussion and refocusing on how sonication governs molecular aggregation and film morphology.", "reviewer_2": "In this manuscript, the authors present an innovative strategy to enhance the performance of organic solar cells (OSCs) by employing ultrasonic treatment to induce J-aggregation in non-fullerene acceptor solutions processed with non-halogenated solvents. This approach of modulating molecular aggregation in non-halogenated solvents using external physical fields is innovative. This work also integrates multi-scale simulations, in situ spectroscopy, advanced morphological characterization, and transient dynamics to elucidate the mechanism. Thus, I recommend acceptance after minor revisions to clarify methodology details and strengthen data interpretation.\n1. Although the paper identifies 40 kHz, 720 W, and 3 minutes as the optimal ultrasonic parameters, the detailed optimization process for selecting these values is insufficiently described. For instance, the authors do not elaborate on how they balanced the combined effects of ultrasonic power, frequency, and duration on solution and film properties when determining these parameters. It remains unclear whether temperature variations in the solution (potentially caused by energy conversion) during sonication were considered. Furthermore, when investigating the impact of different frequencies in Figure S3 (Supporting Information), a power of 300 W was used. It would be beneficial for the authors to provide further clarification in future revisions, particularly regarding:\n(a) The balancing methodology for power/frequency/duration effects,\n(b) Consideration of solution temperature variations during sonication,\n(c) The rationale for using 300 W in Figure S3 while designating 720 W as optimal,\n(d) The unaddressed influence of sonication time on the molecular aggregation process.\n2. The comparative analysis of device performance parameters in binary blends before and after sonication reveals enhanced open-circuit voltage (Voc). Given the authors' emphasis on ultrasound-induced suppression of molecular vibrations and reduced non-radiative recombination, it is recommended to provide detailed energy loss quantification to substantiate the role of ultrasonic treatment in minimizing voltage losses.\n3. As shown in Figure 2h−i, the control device exhibits excessively large phase domains (acceptor: 50−70 nm; donor: 50−100 nm), significantly exceeding the reported exciton diffusion length (29.66 nm, Supplementary Table 7). The apparent contradiction between this morphology and the high PCE of 17.8% requires clarification.\n4. The author mentioned on page 12: \"which indicated that sonication facilitated exciton delocalization. It can effectively reduce the dependence of exciton dissociation on the D/A interface.\" Please cite relevant literature for proof.\n5. Generally, more ordered molecular packing reduces heat generation from molecular vibrations. As noted on page 15 of the manuscript, “sonication-induced structural tuning with ordered J-aggregate geometry allows for rapid thermal energy re- distribution and dissipation···”. Relevant literature should be cited to support this claim.\n6. The manuscript indicates that the sonicated L8-BO film promotes intra-moisty delocalized exciton (i-DE) generation while simultaneously exhibiting extended exciton diffusion length. However, the text primarily emphasizes enhanced exciton delocalization. Can the individual contributions of these two effects be quantitatively distinguished?\n7. While ultrasonic treatment of the acceptor solution enhances exciton dissociation and reduces nonradiative recombination, does it also can promote ordered stacking in the donor material? Additionally, considering the complexity of layer-by-layer processing, is this method directly applicable to donor-acceptor blend solutions?", "reviewer_3": "The manuscript by Zhou and coworkers reports an interesting method based on sonication to induce J-aggregation in non-fullerene-based solar cells processed in non-chlorinated solvents. This results in PCE exceeding 80% due to a combination of enhanced FF, resulting from the improved microstructure, and Jsc, resulting from enhanced light-to-current conversion, as demonstrated by ultra-fast spectroscopy measurements. Moreover, the authors demonstrated the universality of this approach with a variety of blend systems (and ternary). Overall, this is an interesting work, which should be considered in Nature Communications. However, I suggest the following comments/additions before proceeding further.\n1) The morphological analyses are based on GIWAXS data. However, the quality of the 2D plots is quite poor, making it difficult to fully appreciate the line cut (1D) and therefore the relative analyses. I suggest performing higher-quality measurements and extracting the relevant parameters based on the new images.\n2) Figure 5b shows the EQE plots of sonicated and control devices. According to the previous data, the L8BO absorption peak is shifted due to J-aggregation; however, this is not evident in the EQE plot. The authors should comment on this. In addition, EQE approaching 90% should always be paired with IQE measurements.\n3) An in-depth investigation of the degradation processes should be reported. As it stands, the results, albeit interesting, are phenomenological without providing any further insight into why the sonicated samples are more stable than the controls.\n4) Figure 3g shows the dynamics of each component of the exciton to charge conversion, with the sonicated samples featuring longer CS, however, in Figure 4d (TRIR) the sonicated samples are now shorter-lived (in the same time scale). The authors should comment on that."}, "author_response": "Point-by-point response to the reviewers’ comments\nOn behalf of my co-authors, we sincerely appreciate the editors and reviewers for the careful\nreview and insightful comments on our manuscript entitled “Sonication-induced J-aggregation\nin nonhalogenated solvent boosts exciton delocalization for high-efficiency organic solar cells”\n(No. NCOMMS-25-46470). These suggestions are very helpful for improving the quality of the\nmanuscript. We have studied all reviewers’ comments and revised the manuscript accordingly.\nAll the corrections are highlighted in red in the revised manuscript. We hope that the changes\nthus implemented in the revised manuscript meet the requirements for publication in Nature\nCommunications. Point-by-point response to the reviewers’ comments are summarized below.\nREVIEWER COMMENTS\nReviewer #1 (Remarks to the Author):\nThe manuscript describes an ultrasound-assisted, non-halogenated processing route that\nconverts disordered aggregates of Y-series non-fullerene acceptors into ordered J-aggregates,\nas evidenced by in-situ photoluminescence, molecular-dynamics (MD) simulations, and\nquantum-chemical calculations. Spin-coated films derived from the sonicated ink exhibit\nmarkedly improved morphology, enabling PM6:L8-BO binary cells to reach a power-\nconversion efficiency (PCE) of 19.43%, while ternary cells exceed 20% (certified 19.84 %).\nDevices retain 80 % of their initial efficiency for >10000 h at 80 °C, and the strategy appears\ntransferrable to other Y-series acceptors. Although technically sound, the work lacks the\nnovelty and depth expected for publication in Nature Communications.\nResponse: We thank the reviewer for thoughtful review of the manuscript and for providing an\ninsightful summary of our findings. We apologize for the insufficient clarity regarding the novel\naspects of the ultrasonic processing method in the original manuscript. Ultrasonic processing\nprovides unique advantages in solution-based systems, primarily driven by intense cavitation\neffects that generate localized extreme conditions and non-thermal energy transfer. Notably, its\nenergy transfer mechanism does not depend on the overall temperature increase of the solution,\nbut instead operates through targeted local effects via microstreaming and shear stress [Phys.\nRev. Lett. 2009, 102, 084302; Ultrason. Sonochem. 2022, 90, 106176; Coord. Chem. Rev. 2025,\n1\n526, 216373]. This can facilitate precise control over molecular aggregation behaviors by\nadjusting the sonication parameters of frequency, power, and duration. The novelty of this work\nlies in proposing an ecofriendly and locally selective regulation of NFA molecular aggregation\nmethod in non-halogenated solvent, revealing the mechanism by which sonication-induced\nmicrostreaming and shear stress drive the formation of J-aggregation to further facilitate exciton\ndelocalization, confirming its effectiveness and universality in developing high-performance\nOSCs. The innovation and interest of this method has also been acknowledged by the other two\nreviewers. Following the reviewer’s comments, we have validated that this method is simple,\nlow-cost, scalable, and compatible with the additive strategy, thus demonstrating its advantages\nin terms of industrial feasibility and cost-effectiveness (see response to your comment 1 below).\nWe hope that the revised presentation in the manuscript can relieve the reviewer’s concern on\nthe novelty of this work.\nIn the original manuscript, we have systematically investigated the sonication-mediated control\nover the aggregation states of NFAs to enhance exciton delocalization, primarily focusing on:\n(1) mechanistic insights into the sonication-induced formation of J-aggregation, (2) its resultant\neffects on active layer morphology and exciton/charge behaviors, and (3) device-performance\nimprovements in efficiency and stability. To address your comments, in the past months, we\nhave taken additional data and redone some analysis to conduct a more in-depth study, and\nmodified the presentation in the main text and Supplementary Information (SI) as detailed\nbelow. We believe that the depth of the revised manuscript is much improved from the original\nversion.\n2\n1. The advantages in terms of industrial feasibility and cost-effectiveness have not been fully\ndemonstrated. In recent years, numerous studies have reported non-halogenated-solvent-\nprocessed organic solar cells with PCEs above 20%. For example, Professor Liu Feng’s group\nachieved over 20% PCE using a dual-additive strategy in non-halogenated solvents (Adv. Mater.\n2025, 2501812) and demonstrated high efficiency in large-area modules. Moreover, Professor\nWang Tao’s team showed that a simple additive enabled L8-BO devices processed in o-xylene\nto reach 19% efficiency (Adv. Mater. 2023, 35, 2208211). Compared with these works,\nalthough the authors obtain similar results, their manuscript does not meet Nature\nCommunications’ standards for novelty and breakthrough. More importantly, unlike the\nadditive approach, the simplicity, cost, and scalability of ultrasonic processing—particularly\nfor roll-to-roll fabrication—require careful and in-depth evaluation.\nResponse: We thank the reviewer for pointing out this issue and the constructive comment. We\nhave condensed the reviewer’s inquiries into four sub-questions: (1) industrial feasibility of\nultrasonic processing for the roll-to-roll fabrication, (2) simplicity and cost-effectiveness of\nultrasonic processing, (3) compatibility of ultrasonic processing with the additive strategy and\n(4) photovoltaic performance of ultrasonic processing.\n(1) To elucidate the industrial feasibility of the ultrasonic processing method, we have\nfabricated the flexible organic solar cells via the roll-to-roll technique in air. The corresponding\nJ-V and EQE curves are shown in Figure R1 (Supplementary Fig. 38) and Table 23 in the\nrevised SI. The flexible OSCs (1 cm2) with ultrasonic processing present enhanced PCEs\n(14.04%) compared to the control devices (12.06%), demonstrating the potential of the\nultrasonic processing method for scalable industrial application in future manufacturing process.\nEQE curves of bulk heterojunction (BHJ)-type devices fabricated via the roll-to-roll technique\nin air. c, The statistics of the optimized PCEs (10 individual devices).\nSupplementary Table 23. Photovoltaic parameters of the PM6:L8-BO-based flexible BHJ-\ntype OSCs (1 cm2) under AM 1.5G/100 mW cm−2 illumination.\nJ J Cal V FF PCEa\nSC SC OC\nActive layer\n(mA cm−2) (mA cm−2) (V) (%) (%)\n12.06\nPM6:L8-BO 21.71 20.87 0.826 67.28\n(11.79 ± 0.23)\n14.04\nPM6:L8-BO-sonicated 23.89 22.85 0.828 71.00\n(13.87 ± 0.15)\naAverage PCEs with standard deviations determined using 10 individual devices.\nCalIntegrated J values obtained using external quantum efficiency measurements.\nSC\nOn Page 18 in the revised manuscript, we have added relevant descriptions as follows:\n“To explore the potential of the sonication strategy for scalable industrial application, we\nfabricated flexible devices (1 cm2) using the roll-to-roll technique in air. The devices were\nfabricated using an inverted structure of PET/Ag-grid/PH1000/ZnO/active layer/MoO /Ag. The\nx\ndetailed fabrication process is presented in the Supplementary Information. The J-V curves and\ndevice parameters are shown in Supplementary Fig. 38 and Supplementary Table 23. The\ncontrol devices exhibited a PCE of 12.06%, a V of 0.826 V, a J of 21.71 mA cm−2, and a\nOC SC\nFF of 67.28%. After sonication, the device performance was improved, with a PCE of 14.04%,\na V of 0.828 V, a J of 23.89 mA cm−2, and a FF of 71.00%. The corresponding EQE spectra\nOC SC\n4\nare shown in Supplementary Fig. 38b, with the integration current error controlled within 5%.\nThe significant improvement in device performance indicates that the sonication strategy is also\neffective for devices prepared by the roll-to-roll technique, which holds critical implication for\ntheir industrial production.”\nOn Page 5 in the revised SI, we have added relevant descriptions of fabricating flexible OSCs\nusing the roll-to-roll technique as follows:\n“Fabrication of flexible solar cells via the roll-to-roll technique\nSilver-grid-patterned PET substrates (1.5 Ω sq⁻¹, T ≥ 85%) were employed as the bottom\nelectrode, with the pattern designed and fabricated by Suzhou NanoGrid Technology Co., Ltd.\nA mini-roll coater (FOM Technologies, Denmark) served as the roll-to-roll system. The flexible\nBHJ-type solar cells were fabricated under ambient conditions, adopting the inverted device\narchitecture of PET/Ag-grid/PH1000/ZnO/active layer/MoO /Ag. The Poly(3,4-\nx\nethylenedioxythiophene):polystyrene sulfonate (Clevios PH1000) was diluted with isopropanol\n(1:4 v/v) and slot-die-coated onto the PET/Ag-grid substrates at an injection rate of 3.5 µL s⁻¹\nand a roller speed of 10 mm s⁻¹. The hybrid electrodes were baked at 120 °C for 20 min in\nambient air. The ZnO layer was deposited via slot-die coating using a ZnO sol–gel precursor\n(15 mg mL⁻¹ in isopropanol) at an injection rate of 1.2 µL s⁻¹ and a roller speed of 10 mm s⁻¹.\nThe active layer solutions were prepared in o-XY (total concentration: 20 mg mL⁻¹) with a\ndonor:acceptor weight ratio of 1:1, supplemented with 0.25 vol% DIO as a processing additive.\nThe blend solutions were further optimized through sonication prior to deposition. The active\nlayers were slot-die-coated at a roller temperature of 80 °C, with an injection rate of 1.6 µL s⁻¹\nand a roller speed of 13 mm s⁻¹ under ambient conditions. Subsequently, the samples were\ntransferred to a thermal evaporation chamber for top electrode deposition. Finally, at a vacuum\nlevel of ≈1.0 × 10⁻⁶ mbar, a 10 nm MoO buffer layer and a 160 nm Ag electrode were\nx\nsequentially evaporated through shadow masks. The active area of single cells was 1 cm².”\n5\n(2) The ultrasonic processing method also provides distinct advantages in terms of simplicity\nand cost-effectiveness. This technique has been extensively utilized for cleaning the substrates\nin organic and perovskite photovoltaic devices. Especially, the ultrasonic equipment only\nrequires standard ultrasonic generators and transducers, and eliminates complex reaction\nvessels and high-vacuum as well as high-pressure systems (simplicity of equipment). Ambient\ntemperature and pressure operation of the ultrasonic processing method reduces auxiliary\nequipment needs (low operational cost). Furthermore, this technique can be directly integrated\ninto the existing production lines and presents good compatibility with the solvent systems and\nadditive strategy (process compatibility). Therefore, considering that the target of ultrasonic\nprocessing is solely the solution itself, implementing the simple and short-duration ultrasonic\nprocessing does not add complex device fabrication processes.\n(3) We apologize for the insufficient clarity regarding the compatibility of ultrasonic processing\nwith the additive strategy in the original manuscript. The reviewer has thoughtfully referenced\nsome recent advances in the additive strategy for non-halogenated solvents, providing valuable\ncontext that prompts us to further clarify the distinct aspects of this work. Crucially, the primary\nfocus of this work does not aim to compare the merits or drawbacks of ultrasonic processing\nrelative to other strategies. Instead, this work focuses on elucidating the mechanism of the novel\nultrasonic processing, which is an unexplored strategy in the field of organic photovoltaic, using\nmicrostreaming and shear stress to induce J-aggregation formation of NFAs to enhance exciton\ndelocalization in non-halogenated solvents, thereby providing an effective and general method\nfor developing high-performance OSCs. We quite agree with the reviewer that the additive\nstrategy is advantageous to fabricate state-of-the-art OSCs. Especially, ultrasonic processing\npresents excellent compatibility with the additive strategy. In the original manuscript, the L8-\nBO solution (10 mg/ml in o-XY) with 0.25 vol% DIO was subjected to ultrasonic processing\nat 40 kHz and 720 W for 3 min. The target OSCs based on PM6:L8-BO exhibit an enhanced\nPCE of 19.43%, compared to 17.50% for the control devices processed with DIO. To evaluate\nthis further, we also selected a common solid additive, 1,4-diiodobenzene (DIB), to assess its\ncompatibility with ultrasonic processing. Results are shown in Figure R2 (Supplementary Fig.\n6\n8a, 33b) and Table 17 in the revised SI. The PM6:L8-BO solar cells processed simultaneously\nwith sonication and DIB achieve a maximum PCE of 19.31%, which is superior to 18.86%\nobtained for the control devices processed with DIB. Collectively, these results demonstrate the\nsuperior compatibility of ultrasonic processing with the additive strategy. We hope that the\npresented results and discussion can relieve the reviewer’s concern regarding the novelty of\nultrasonic processing.\nFigure R2 (Supplementary Fig. 8a and 33b) The analysis of the L8-BO-DIB-sonicated\ndevices. a, Evolution of the PL spectra of the L8-BO-DIB solution during sonication (frequency:\n40 kHz, power: 720 W). b, J-V curves of the PM6:L8-BO-DIB-based devices without and with\nsonication.\nSupplementary Table 17. Photovoltaic parameters of the PM6:L8-BO-DIB-based OSCs\nwithout and with sonication.\nCondition (720 W, 40 J V FF PCEa\nSC OC\nActive layer\nkHz, 3 min) (mA cm-2) (V) (%) (%)\n18.86\nL8-BO-DIB 26.99 0.876 79.76\nPM6:L8-BO (18.64 ± 0.16)\n(o-XY) 19.31\nL8-BO-DIB-sonicated 27.49 0.877 80.09\n(19.18 ± 0.13)\naAverage PCEs with standard deviations determined using 10 individual devices.\nOn Page 3 in the revised SI, we have added relevant descriptions of the compatibility between\n7\nsonication and additive as follows:\n“Notably, sonication presents excellent compatibility with the additive strategy. In this work,\nthe solution of L8-BO (10 mg/ml in o-XY) with 0.25 vol% DIO was subjected to sonication at\n40 kHz and 720 W for 3 min. The target OSCs based on PM6:L8-BO exhibit an enhanced PCE\nof 19.43%, compared to 17.50% for control devices processed with DIO. To evaluate this\nfurther, we selected a solid additive, 1,4-diiodobenzene (DIB), to assess its compatibility with\nsonication. A slight redshift is observed in the in-situ PL spectra (Supplementary Fig. 8a). The\nPM6:L8-BO solar cells processed simultaneously with sonication and DIB achieve a maximum\nPCE of 19.31%, superior to the 18.86% obtained for the control devices processed with DIB\n(Supplementary Fig. 33b and Table 17). These results demonstrate good compatibility of\nsonication with the additive strategy.”\n(4) Regarding device performance of ultrasonic processing, our reported PCE of 20.41% for\nthe PM6:D18:L8-BO in o-XY exceeds values in recent studies cited by the reviewer: 20.0% for\nthe PM6:PY-IT:L8-BO in o-XY [Adv. Mater. 2025, 37, 2501812] and 19.0% for the D18:L8-\nBO in toluene [Adv. Mater. 2023, 35, 2208211]. Undoubtedly, the research groups led by Prof.\nLiu Feng and Prof. Wang Tao frequently achieve and report high device efficiency. It should\nbe noted that the differences of solvent types and material systems may complicate direct\ncomparison of device parameters. Notably, the effectiveness and universality of ultrasonic\nprocessing, and the compatibility with other strategies present its potential to achieve further\nperformance breakthroughs of OSCs in non-halogenated solvents. This interesting issue is very\nworthwhile to research in our future work. Herein, we choose to present this interesting issue\nand leave the discussion open for further study. We hope that all the discussion can relieve the\nreviewer’s concern regarding the breakthrough of ultrasonic processing.\n8\n2. From the authors’ optimization data, the ultrasound-assisted process appears to operate\nwithin a very narrow window, which could hinder its broader adoption. Ultrasonic treatment\nrequires tight control over 3 parameters (frequency, power, duration) and Supplementary Tables\n9 and 10 shows that small changes in any one of these can dramatically affect device\nperformance. For example, at 40 kHz and 720 W, a 3-minute treatment yields a PCE of ~19.5%,\nwhile extending to 4 minutes drops it to ~18.5%. Such sensitivity undermines the method’s\nindustrial viability. I therefore recommend that the authors provide a more detailed, quantitative\nanalysis of how each of the parameters influences J-aggregate formation.\nResponse: We thank the reviewer for pointing out this issue and the constructive comment. We\nhave condensed the reviewer’s inquiries into two sub-questions: (1) operating window and\nsensitivity of ultrasonic processing and (2) quantitative analysis of how the frequency, power,\nand duration of ultrasonic processing influencing the formation of J-aggregation.\n(1) To address the reviewer’s concern regarding the operating window and sensitivity of\nultrasonic processing, we have systematically re-evaluated the impact of frequency, power, and\nduration on photovoltaic performance by re-fabricating OSCs and combining previously\nobtained data. Statistical analysis of device data confirm that ultrasonic processing exhibits a\nrelatively broad operational window (i.e., low sensitivity). Of note is that the optimal conditions\nof ultrasonic processing (40 kHz, 720 W, and 3 min) can be precisely achieved in industrial\nproduction, demonstrating the potential of this realized sonication technology for widespread\nadoption and industrial viability in organic photovoltaics. To determine the optimal sonication\nparameters, we first fixed the power in order to identify the optimal frequency and duration.\nSubsequently, both frequency and duration were held constant to determine the optimal power.\nFinally, both frequency and power were maintained to confirm the optimal duration. Results\nare shown in Figure R3-4 (Supplementary Fig. 31-32) and Table 9-15 in the revised SI.\nMoreover, we apologize for previous misleading expressions of the duration-dependent effects\non device performance. The related corrections are presented in Figure R4 (Supplementary\nFig. 32) and Table 15 in the revised SI.\nsonication conditions. a-d, J–V curves of the devices and e-h, statistics of the optimized PCEs\nwith different sonication duration and frequency.\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 20 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\n17.71\nL8-BO-sonicated\n25.64 0.879 78.57 (17.55 ±\n(1 min)\n0.15)\n17.88\nL8-BO-sonicated\nPM6:L8-BO 25.82 0.881 78.58 (17.66 ±\n(2 min)\n(o-XY) 0.13)\nL8-BO-sonicated 18.02\n26.05 0.880 78.61\n(3 min) (17.89 ± 0.12)\nL8-BO-sonicated 17.95\n25.99 0.879 78.59\n(4 min) (17.74 ± 0.14)\nL8-BO-sonicated 17.82\n25.86 0.877 78.56\n(5 min) (17.65 ± 0.12)\naAverage PCEs with standard deviations determined using 10 individual devices.\nSupplementary Table 10. Photovoltaic parameters of the PM6:L8-BO-based OSCs (explored\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 40 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 17.81\n25.78 0.879 78.60\n(1 min) (17.60 ± 0.14)\nL8-BO-sonicated 18.04\n26.06 0.880 78.65\nPM6:L8-BO (2 min) (17.80 ± 0.15)\n(o-XY) L8-BO-sonicated 18.18\n26.21 0.881 78.72\n(3 min) (17.97 ± 0.11)\nL8-BO-sonicated 18.08\n26.09 0.881 78.66\n(4 min) (17.79 ± 0.20)\nL8-BO-sonicated 17.99\n26.04 0.879 78.61\n(5 min) (17.71 ± 0.17)\naAverage PCEs with standard deviations determined using 10 individual devices.\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 60 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 17.65\n25.57 0.880 78.45\n(1 min) (17.39 ± 0.18)\nL8-BO-sonicated 17.71\n25.69 0.881 78.26\nPM6:L8-BO (2 min) (17.48 ± 0.19)\n(o-XY) L8-BO-sonicated 17.76\n25.83 0.880 78.13\n(3 min) (17.60 ± 0.15)\nL8-BO-sonicated 17.69\n25.84 0.877 78.06\n(4 min) (17.41 ± 0.22)\nL8-BO-sonicated 17.61\n25.78 0.876 77.98\n(5 min) (17.29 ± 0.27)\naAverage PCEs with standard deviations determined using 10 individual devices.\nSupplementary Table 12. Photovoltaic parameters of the PM6:L8-BO-based OSCs (explored\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 80 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 17.41\n25.27 0.880 78.29\n(1 min) (17.24 ± 0.13)\nL8-BO-sonicated 17.36\n25.27 0.878 78.15\nPM6:L8-BO (2 min) (17.10 ± 0.17)\n(o-XY) L8-BO-sonicated 17.28\n25.24 0.877 78.06\n(3 min) (17.09 ± 0.12)\n17.14\nL8-BO-sonicated\n25.09 0.876 77.98 (16.89 ±\n(4 min)\n0.18)\nL8-BO-sonicated 25.01 0.875 77.91 17.05\n12\n(5 min) (16.77 ±\n0.14)\naAverage PCEs with standard deviations determined using 10 individual devices.\nFigure R4 (Supplementary Fig. 32) J–V curves of the devices prepared under different\nsonication conditions. a-c, J–V curves of the devices and d-f, statistics of the optimized PCEs\nwith different frequency, power, and duration.\nSupplementary Table 13. Photovoltaic parameters of the PM6:L8-BO-based OSCs (explored\nunder different sonication frequency using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 3 min) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 18.02\n26.13 0.880 78.38\nPM6:L8-BO (20 kHz) (17.89 ± 0.12)\n(o-XY) L8-BO-sonicated 18.18\n26.21 0.881 78.72\n(40 kHz) (17.97 ± 0.11)\nL8-BO-sonicated 17.76\n25.83 0.880 78.13\n(60 kHz) (17.61 ± 0.15)\n25.24 0.877 78.06\n(80 kHz) (17.02 ± 0.21)\naAverage PCEs with standard deviations determined using 10 individual devices.\nSupplementary Table 14. Photovoltaic parameters of the PM6:L8-BO-based OSCs (explored\nunder different sonication power using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(40 kHz, 3 min) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 18.18\n26.21 0.881 78.72\n(300 W) (17.97 ± 0.11)\nL8-BO-sonicated 18.52\n26.59 0.879 79.24\n(430 W) (18.31 ± 0.14)\nPM6:L8-BO L8-BO-sonicated 18.79\n26.87 0.878 79.64\n(o-XY) (560 W) (18.51 ± 0.15)\nL8-BO-sonicated 19.01\n26.95 0.879 80.24\n(640 W) (18.80 ± 0.14)\nL8-BO-sonicated 19.43\n27.05 0.881 81.53\n(720 W) (19.22 ± 0.16)\nL8-BO-sonicated 19.16\n27.08 0.880 80.41\n(800 W) (18.96 ± 0.12)\naAverage PCEs with standard deviations determined using 10 individual devices.\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(720 W, 40 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 18.26\n26.23 0.879 79.19\n(720 W, 1 min) (17.98 ± 0.18)\nL8-BO-sonicated 19.04\n26.87 0.883 80.23\n(720 W, 2 min) (18.85 ± 0.14)\nL8-BO-sonicated 19.43\n27.05 0.881 81.53\n(720 W, 3 min) (19.22 ± 0.16)\nPM6:L8-BO L8-BO-sonicated 19.13\n27.08 0.880 80.27\n(o-XY) (720 W, 4 min) (18.96 ± 0.11)\nL8-BO-sonicated 18.96\n26.96 0.879 79.99\n(720 W, 5 min) (18.75 ± 0.13)\nL8-BO-sonicated 18.72\n26.61 0.882 79.76\n(720 W, 6 min) (18.53± 0.12)\nL8-BO-sonicated 18.53\n26.44 0.880 79.65\n(720 W, 7 min) (18.35 ± 0.15)\nL8-BO-sonicated 18.24\n26.22 0.876 79.41\n(720 W, 8 min) (18.06 ± 0.12)\naAverage PCEs with standard deviations determined using 10 individual devices.\n(2) Following the reviewer’s comment, we have provided a more detailed, quantitative analysis\nof how the frequency, power, and duration of ultrasonic processing influencing the formation\nof J-aggregation by performing in-situ PL measurements on L8-BO solution. Results are shown\nin Figure R5-8 (Supplementary Fig. 2-5) in the revised SI. Sonication is usually accompanied\nby physical and chemical effects. As the frequency increases, the physical mechanical effects\ngradually weaken [Chem. Eur. J. 2019, 25, 5372–5388]. When the frequency is 20 kHz, the\nrelatively large shear stress can destroy the aggregation of NFAs, while the frequency above 40\nkHz, the shear stress is too small to drive the formation of J-aggregation. Therefore, the extent\nof PL spectral redshift first increases and then decreases (Supplementary Fig. 2). As the\nsonication power increases, the effects of shear stress become increasingly strong. Once the\neffect reaches a certain intensity, it further causes molecular slippage, disrupting the original J-\n15\naggregation, thus reducing the degree of redshift (Supplementary Fig. 3). According to\nquantitative analysis of the degree of PL spectral redshift, it can be concluded that the optimal\nfrequency (40 kHz) and power (720 W) play an obvious role in promoting the formation of J-\naggregation. In addition, with the increase of sonication duration, the PL spectra present a\ncontinuous redshift (Supplementary Fig. 4-5). This demonstrates the degree of molecular\naggregation continues to enhance as long as the shear stress remains constant. Combined with\nthe device data, it can be concluded that excessive molecular aggregation is detrimental to the\nphotovoltaic performance.\nFigure R5 (Supplementary Fig. 2) In-situ PL spectra. a-d, Evolution of the PL spectra of the\nL8-BO solution during sonication with different frequency (power: 300 W).\nL8-BO solution during sonication with different power (frequency: 40 kHz).\nFigure R7 (Supplementary Fig. 4) In-situ PL spectra. Evolution of the PL spectra of the L8-\nBO solution during sonication with different duration (frequency: 40 kHz, power: 720 W).\nsolution after sonication. The redshift degree extracted from the PL spectra with different\nsonication a, frequency, b, power, and c, duration.\nOn Page 1 in the revised SI, we have added relevant descriptions of the optimal conditions of\nsonication as follows:\n“To determine the optimal sonication parameters, we have systematically studied the effects of\nfrequency, power, and duration on molecular aggregation and photovoltaic performance by\nperforming in-situ PL measurements and fabricating organic solar cells (OSCs). We first fixed\nthe power in order to identify the optimal frequency and duration. Subsequently, the frequency\nand duration were held constant to determine the optimal power. Finally, the frequency and\npower were maintained to confirm the optimal duration. The in-situ PL spectra of the L8-BO\nsolution are displayed in Supplementary Fig. 2-4. Sonication is usually accompanied by\nphysical and chemical effects. As the frequency increases, the physical mechanical gradually\nweakens. When the frequency is 20 kHz, the relatively large shear stress can destroy the\naggregation, while the frequency above 40 kHz, the shear stress is too small to drive the\nformation of J-aggregation. Therefore, the redshift of the PL spectrum first increases and then\ndecreases. As the sonication power increases, the effects of shear stress become increasingly\nstrong. Once the effect reaches a certain intensity, it further causes molecular slippage,\ndisrupting the original J-aggregation, thereby reducing the degree of redshift. According to\nquantitative analysis of the degree of PL spectral redshift (Supplementary Fig. 5), it can be\nconcluded that the optimal frequency (40 kHz) and power (720 W) play an obvious role in\npromoting the formation of J-aggregation. In addition, with the increase of sonication time, the\nPL spectra show a continuous redshift. This demonstrates the degree of molecular aggregation\n18\ncontinues to enhance as long as the shear stress remains constant. Device data are shown in\nSupplementary Fig. 31-32 and Table 9-15. The optimal conditions of sonication are determined\nto be 40 kHz, 720 W, and 3 min. Combined with in-situ PL data, it can be concluded that\nexcessive molecular aggregation is detrimental to device performance.”\n3. More data on solution stability after sonication are needed. It is crucial to know how long the\nsonication-induced aggregation persists, yet the authors only report results at 1 mins post-\ntreatment, which is insufficient to demonstrate the durability of the induced structure. I\nrecommend extending the observation period to several hours or even days to track the\nevolution of the aggregation state over time. At the same time, a thermodynamic analysis of the\nJ-aggregate stability mechanism should be included.\nResponse: We thank the reviewer for the constructive comments. We have condensed the\nreviewer’s inquiries into two sub-questions: (1) solution stability after sonication and (2)\nthermodynamic analysis of the J-aggregation stability mechanism.\n(1) The stability of solution after ultrasonic processing was studied by performing in-situ PL\nmeasurements. Results are shown in Figure R9 (Supplementary Fig. 10) in the revised SI.\nThe evolution of PL spectra and peak position over time (10 days) demonstrate superior stability\nof sonication-induced J-aggregation in solution.\nafter sonication. a, PL spectra and b, peak position changes at several days after stopping\nsonication.\nOn Page 4 in the revised manuscript, we have added relevant descriptions as follows:\n“Notably, J-aggregation was well maintained in the solution within ten days after sonication\nwas stopped (Supplementary Fig. 10), which was sufficient for spin-coating preparation of films\nand industrial production.”\n(2) Following the reviewer’s suggestion, a thermodynamic analysis of the J-aggregate stability\nwas performed by determining the glass transition temperature (T ) from deviation metric\ng\nresults extracting from UV-vis absorption spectra with the increasing thermal annealing\ntemperature [Joule 2021, 5, 2129-2147]. For a quantitative analysis, we have used a deviation\nmetric (DM ) that is the sum of the squared deviation in the absorbance between as-cast and\nT\nannealed films:\n𝜆𝑚𝑎𝑥\n𝐷𝑀 = ∑[𝐼 (𝜆)−𝐼 (𝜆)]2\n𝑇 𝑅𝑇 𝑇\n𝜆𝑚𝑖𝑛\nwhere 𝜆 is the wavelength, and 𝜆 and 𝜆 are the lower and upper bounds of the optical\n𝑚𝑖𝑛 𝑚𝑎𝑥\nsweep, 𝐼 (𝜆) and 𝐼 (𝜆) are the normalized absorption intensities of as-cast (room temperature)\n𝑅𝑇 𝑇\nand annealed films, respectively. Results are shown in Figure R10-11 (Supplementary Fig.\n20\n44-45) in the revised SI. Neat L8-BO films and PM6:L8-BO films with ultrasonic processing\ndeliver the enlarged T compared to that of the control samples. According to the Ade-\ng\nO’Connor-Ghasemi stability framework, the enlarged T demonstrates that sonication-induced\ng\nJ-aggregation can reduce diffusion coefficients of materials and enhance kinetic stabilization of\nfilm morphology [Nat. Mater. 2021, 20, 525-532].\nFigure R10 (Supplementary Fig. 44) UV-vis absorption spectra of neat films at different\ntemperature. Evolution of UV-vis deviation metric as a function of annealing temperature of\nthe L8-BO films a-b, without and c-d, with sonication.\ntemperature. Evolution of UV-vis deviation metric as a function of annealing temperature of\nthe PM6:L8-BO films a-b, without and c-d, with sonication.\n22\n4. The details of the molecular dynamic simulations are incomplete. The authors use MD to\nexplore how the ultrasonic field influences acceptor aggregation, but it is unclear how they\nmodeled the ultrasonic field, how cavitation effects were introduced, and how the acceptor\nmolecules reassemble under cavitation. I recommend that the authors provide a more detailed\ndescription of their MD methodology, including the force fields, solvent models, simulation\nparameters, and any specific procedures used to simulate ultrasound and cavitation.\nResponse: We thank the reviewer for the constructive comments. We apologize for the lack of\nclarity regarding the details of the molecular dynamic simulations in the original SI. Following\nthe reviewer’s suggestion, we have provided a detailed description of the molecular dynamic\nsimulations in the revised SI. Notably, the cavitation effect is a complex process that causes the\ngeneration, oscillation, growth, contraction and violent collapse (implosions) of tiny bubbles\n(cavitation nuclei) when sonication waves propagate in a liquid medium, along with a series of\naccompanying physical and chemical effects [Phys. Rev. Lett. 2009, 102, 084302; Ultrason.\nSonochem. 2022, 90, 106176; Coord. Chem. Rev. 2025, 526, 216373]. Such periodic oscillation\nof the bubbles produces microstreaming and shear stress, providing energy that facilitates the\nformation of J-aggregates. Microstreaming pushes L8-BO molecules to aggregate on the bubble\nsurface. Then the disordered molecules will be oriented and arranged under the effect of shear\nstress, and subsequently become ordered J-aggregation. The surface of the bubbles serves as a\nplatform for modulating molecular aggregation during their periodic oscillation. Herein, as for\nsonication conditions, we used square wave patterns to simulate periodic pressure variations,\nthereby simulating the effect of shear stress stemming from cavitation on molecules. This can\nclearly demonstrate the modulation of NFA molecular aggregation by sonication.\nOn Page 6 in the revised SI, we have added relevant descriptions of the molecular dynamics\nsimulation as follows:\n“Gromacs2022 was selected as the molecular dynamics simulation software. The General\nAmber Force Field (GAFF) was utilized for small molecules. The Transferable Interatomic\nPotential with Three Points (TIP3P) model was used for water molecules. A simulation box\nwith dimensions of 10 nm × 10 nm × 18 nm was constructed, ensuring that the edges of the box\nwere at least 1.2 nm away from the molecular boundaries. Each system contained 20 L8-BO\n23\nmolecules and 6147 o-xylene molecules. Periodic pressure variations were simulated using\nsquare wave patterns to replicate sonication conditions. The Particle-Mesh Ewald (PME)\nmethod was employed to address electrostatic interactions, and energy minimization was\nconducted using the steepest descent algorithm with a maximum of 50,000 steps. Both\nCoulombic force cutoff and van der Waals radius cutoff were set to 1 nm. Subsequently, the\nsystem underwent equilibration through both canonical ensemble (NVT) and isothermal-\nisobaric ensemble (NPT) methods, followed by a molecular dynamics simulation lasting for\n100 ns under standard temperature and pressure conditions. The non-bonded interaction cutoff\nwas established at 10 Å. A Langevin thermostat maintained the simulation temperature at 300\nK while pressure control was achieved using the C-rescale method.”\n5. In materials research, when molecular solubility is limited, it is common to either raise the\nsolution temperature or apply ultrasonication. The authors should clarify how the aggregation\nstate produced by sonication differs from that obtained by simple heating. Furthermore, because\nsonication often induces a temperature rise, the authors need to monitor the solution temperature\nduring sonication treatment and distinguish the intrinsic mechanical effects of ultrasound from\nany thermal contributions.\nResponse: We thank the reviewer for the constructive comments. We have condensed the\nreviewer’s inquiries into two sub-questions: (1) difference in regulating molecular aggregation\nof ultrasonic processing and simple heating and (2) solution temperature variations during\nsonication.\n(1) As indicated in the original SI, the L8-BO solution was initially stirred at 80 ℃ for 12 hours\nto ensure complete dissolution. After cooling to room temperature, we carried out ultrasonic\nprocessing on the L8-BO solution. To clarify the difference in regulating the aggregation state\nof ultrasonic processing and simple heating, we have conducted in-situ PL measurements on\nthe L8-BO solution during the process of stirring at 80 °C for 12 hours and subsequent cooling\nto room temperature, to track the evolution of the aggregation state. Results are shown in Figure\nR12 (Supplementary Fig. 6a-c) in the revised SI. During the heating and stirring process, the\nPL spectra exhibit a continuous blueshift, whereas they display a continuous redshift when the\n24\nsolution is cooled to room temperature. Ultimately, a slight redshift is observed in the PL\nspectra. In contrast, the evolutionary process of the aggregation state in L8-BO solution\nsubjected solely to ultrasonic processing (without heating) was also monitored by in-situ PL\nmeasurements. Results are shown in Figure R12 (Supplementary Fig. 6d) in the revised SI.\nDuring the ultrasonic processing process, the PL spectra present a continuous redshift. This\nindicates the positive effect of ultrasonic processing in promoting the formation of J-\naggregation. In summary, sonication can induce redshift in the PL spectra of L8-BO solution,\nwhile simple heating tends to induce blueshift in the PL spectra.\nFigure R12 (Supplementary Fig. 6) In-situ PL spectra. Evolution of the PL spectra of the\nL8-BO solution during a, heating dissolution and b, cooling processes. c, Evolution of the\nPL spectra of the L8-BO solution before and after heating and cooling processes. d, Evolution of\nthe PL spectra of the unheated L8-BO solution during sonication (frequency: 40 kHz, power:\napplication on device performance. Based on Fig. 5a in the original manuscript, we have added\nperformance data for devices subjected solely to ultrasonic processing. Results are shown in\nFigure R13 (Supplementary Fig. 33a and Table 16) in the revised SI. Devices subjected\nsolely to ultrasonic processing show higher PCE (19.14%) than those treated solely with simple\nheating (17.50%), but lower PCE (19.14%) than devices subjected to combined thermal and\nultrasonic processing (19.43%). This demonstrates the advantage of combined thermal and\nultrasonic processing on modulating molecular aggregation and enhancing device performance.\nFigure R13 (Supplementary Fig. 33a) J–V curves of the devices. J-V curves of the devices\nprepared using the L8-BO solution under different conditions.\nSupplementary Table 16. Photovoltaic parameters of the PM6:L8-BO-based OSCs prepared\nusing the L8-BO solution treated directly by sonication without heating and dissolution.\nCondition (720 W, 40 J V FF PCEa\nSC OC\nActive layer\nkHz, 3 min) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nPM6:L8-BO L8-BO-sonicated 19.14\n27.14 0.880 80.13\n(o-XY) (unheated) (18.93 ± 0.17)\n19.43\nL8-BO-sonicated 27.05 0.881 81.53\n(19.22 ± 0.16)\naAverage PCEs with standard deviations determined using 10 individual devices.\n26\n(2) Following the reviewer’s suggestion, we have monitored the solution temperature during\nthe process of ultrasonic processing. Results are shown in Figure R14 (Supplementary Fig.\n7). The related video is presented as an additional Supplementary file. It can be clearly seen\nthat the temperature of the solution slightly increases from 24.1 ℃ to 26.2 ℃ (from 297.1 K to\n299.2 K) throughout the sonication process. This suggests that the temperature increase\nresulting from sonication can be disregarded in practical applications. Hence, the formation of\nJ-aggregation in solution is attributed to the intrinsic mechanical effects of sonication.\nFigure R14 (Supplementary Fig. 7) Temperature changes of solution during sonication.\nTemperature of the L8-BO solution after different time of sonication.\nOn Page 2 in the revised SI, we have added relevant descriptions as follows:\n“In materials research, limited molecular solubility is commonly addressed by either elevating\nsolution temperature or employing sonication. In this work, the L8-BO solution was initially\nstirred at 80 ℃ for 12 hours to ensure complete dissolution. After cooling to room temperature,\nwe further carried out sonication on the L8-BO solution. To clarify the difference in regulating\naggregation states of heating, sonication, and their combined application, we conducted in-situ\nPL measurements on the L8-BO solution to track the evolution of aggregation states. Results\nare shown in Supplementary Fig. 6. During the heating and stirring process, the PL spectra\nexhibit a continuous blueshift (Supplementary Fig. 6a), whereas they display a continuous\nredshift when the solution is cooled to room temperature (Supplementary Fig. 6b). Ultimately,\na slight redshift is observed in the PL spectra (Supplementary Fig. 6c). In contrast, the PL\nspectra present a continuous redshift during sonication without heating (Supplementary Fig.\n27\n6d). In summary, sonication can induce redshift in the PL spectra of L8-BO solution, while\nsimple heating tends to induce blueshift in the spectra. This indicates an obvious impact of\nsonication in promoting the formation of J-aggregation. Notably, the combined application of\nheating and sonication present the further improvement in regulating aggregation behaviours.\nMoreover, we further compared the influence of heating, sonication, and their combined\napplication on photovoltaic performance. Based on Fig. 5a in the manuscript, we added\nperformance data for devices subjected solely to sonication. Results are shown in\nSupplementary Fig. 33a and Table 16. Devices subjected solely to sonication show higher PCEs\n(19.14%) than those treated solely with simple heating (17.50%), but lower PCEs (19.14%)\nthan devices subjected to combined thermal and ultrasonic processing (19.43%). This\ndemonstrates the advantage of their combined application on modulating molecular aggregation\nand enhancing photovoltaic performance. Considering sonication often induces a temperature\nrise, we monitored the temperature of the solution during the sonication process. Results are\nshown in Supplementary Fig. 7. The related video is presented as an additional Supplementary\nfile. It can be clearly seen that the temperature of the solution slightly increases from 24.1 ℃\nto 26.2 ℃ (from 297.1 K to 299.2 K) throughout the sonication process. This suggests that the\ntemperature increase resulting from sonication can be disregarded in practical applications.\nTherefore, the formation of J-aggregation in solution is attributed to the intrinsic mechanical\neffects of sonication.”\n28\n6. The manuscript’s presentation is confusing. A large portion of the text is devoted to charge‐\ntransport and recombination kinetics (like TA, TRIR), yet these improvements actually stem\nfrom morphology changes induced by sonication rather than any direct effect of ultrasound on\ncharge behavior. The repeated use of terms such as “sonication-induced lifetime”,\n“sonication facilitated exciton delocalization”, only adds to the confusion. If the authors wish to\nclaim a direct impact of sonication on exciton delocalization, they should include a side‐by‐side\ncomparison with other morphology‐control methods (for example, additive strategies). I\ntherefore recommend streamlining the charge‐kinetics discussion and refocusing on how\nsonication governs molecular aggregation and film morphology.\nResponse: We thank the reviewer for pointing out this issue and the constructive comment. We\nquite agree with the reviewer that the improvements in exciton and charge behaviors stem from\nmorphology changes induced by ultrasonic processing. Following the reviewer’s comment, we\nhave expanded the discussion on how ultrasonic processing modulates molecular aggregation\nand film morphology in the revised manuscript. Meanwhile, we have simplified the charge‐\nkinetics discussion and deleted the repeated use of terms adding to the confusion.\nOn Page 10 in the revised manuscript, we have added relevant descriptions of morphology\ngoverned by sonication as follows:\n“Conversely, upon sonication, the L8-BO molecules formed ordered J-type aggregation in the\nsolution. This preconstructed ordered aggregation was effectively retained during subsequent\ncrystal growth stages, which promoted ordered molecular stacking and considerably enhanced\n- stacking interactions among molecules. Meanwhile, the sonication strategy optimized the\nphase separation of blend films and facilitated the formation of a fibril network. This sonication-\ninduced morphological optimization can be expected to improve exciton and charge behaviours.”\nOn Page 10 in the revised manuscript, we have rewritten relevant descriptions as follows:\n“The decrease in lifetime of the sonicated films from 0.34 ps to 0.24 ps indicates a concomitant\nincrease in the rate of hole transfer53.”\n“Sonication-induced morphology tuning considerably accelerated excited state decay (i.e., the\n29\nlifetime decreased from 3.89 ps to 2.28 ps) and thus increased the efficiency of exciton\ndissociation (Supplementary Table 6)54. In addition, the extended lifetime of the polaron signals\nobserved at 960 nm revealed that bimolecular recombination was suppressed in the sonicated\nfilm31 (Supplementary Fig. 26c). Supplementary Fig. 26d showed the kinetic curves of the intra-\nmoiety delocalized excitons (i-DE) extracted from TA spectra at 1500 nm55.”\nOn Page 12 in the revised manuscript, we have rewritten relevant descriptions as follows:\n“After sonication, the contribution of the pathway dominated by i-DE states substantially\nincreased (0.54 → 0.6), which indicated that the resulting morphology in the sonicated films\nfacilitate exciton delocalization. It can effectively reduce the dependence of exciton dissociation\non the D/A interface55–57.”\n“These results suggested that the sonication strategy promoted efficient exciton dissociation in\nboth pathways.”\nOn Page 13 in the revised manuscript, we have rewritten relevant descriptions as follows:\n“Based on the aforementioned insights into exciton and charge dynamics, transient infrared\n(TRIR) spectroscopy was used to further examine the effects of the optimized morphology\ninduced by sonication on molecular vibration (Figs. 4a, Supplementary Figs. 27a-c).”\nOn Page 15 in the revised manuscript, we have rewritten relevant descriptions as follows:\n“The sonicated films demonstrated reduced  from 151.2 meV to 113.3 meV (Fig. 4g and\nSupplementary Table 8) and was therefore concluded to inhibit exciton–vibration coupling and\npromote exciton diffusion and polaron transport.”\nIn this manuscript, the authors present an innovative strategy to enhance the performance of\norganic solar cells (OSCs) by employing ultrasonic treatment to induce J-aggregation in non-\nfullerene acceptor solutions processed with non-halogenated solvents. This approach of\nmodulating molecular aggregation in non-halogenated solvents using external physical fields is\ninnovative. This work also integrates multi-scale simulations, in situ spectroscopy, advanced\nmorphological characterization, and transient dynamics to elucidate the mechanism. Thus, I\nrecommend acceptance after minor revisions to clarify methodology details and strengthen data\ninterpretation.\nResponse: We thank the reviewer for the positive comments on this work and recommending\nits publication after some revisions.\n1. Although the paper identifies 40 kHz, 720 W, and 3 minutes as the optimal ultrasonic\nparameters, the detailed optimization process for selecting these values is insufficiently\ndescribed. For instance, the authors do not elaborate on how they balanced the combined effects\nof ultrasonic power, frequency, and duration on solution and film properties when determining\nthese parameters. It remains unclear whether temperature variations in the solution (potentially\ncaused by energy conversion) during sonication were considered. Furthermore, when\ninvestigating the impact of different frequencies in Figure S3 (Supporting Information), a power\nof 300 W was used. It would be beneficial for the authors to provide further clarification in\nfuture revisions, particularly regarding:\n(a) The balancing methodology for power/frequency/duration effects,\nResponse: We thank the reviewer for the constructive comment. We apologize for the lack of\nclarity in our previous description of the methodology used to balance frequency, power, and\nduration effects. Following the reviewer’s suggestion, we have systematically re-evaluated the\nimpact of frequency, power, and duration on photovoltaic performance by re-fabricating OSCs\nand combining previously obtained data. To determine the optimal sonication parameters, we\nfirst fixed the power in order to identify the optimal frequency and duration. Subsequently, both\nfrequency and duration were held constant to determine the optimal power. Finally, both\nfrequency and power were maintained to confirm the optimal duration. Results are shown in\nFigure R3-4 (Supplementary Fig. 31-32) and Table 9-15 in the revised SI. The optimal\n31\nconditions of ultrasonic processing are 40 kHz, 720 W, and 3 min.\nFigure R3 (Supplementary Fig. 31) J–V curves of the devices prepared under different\nsonication conditions. a-d, J–V curves of the devices and e-h, statistics of optimized PCE with\ndifferent sonication duration and frequency.\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 20 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 17.71\n25.64 0.879 78.57\n(1 min) (17.55 ± 0.15)\nL8-BO-sonicated 17.88\n25.82 0.881 78.58\nPM6:L8-BO (2 min) (17.66 ± 0.13)\n(o-XY) L8-BO-sonicated 18.02\n26.05 0.880 78.61\n(3 min) (17.89 ± 0.12)\nL8-BO-sonicated 17.95\n25.99 0.879 78.59\n(4 min) (17.74 ± 0.14)\nL8-BO-sonicated 17.82\n25.86 0.877 78.56\n(5 min) (17.65 ± 0.12)\naAverage PCEs with standard deviations determined using 10 individual devices.\nSupplementary Table 10. Photovoltaic parameters of the PM6:L8-BO-based OSCs (explored\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 40 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 17.81\n25.78 0.879 78.60\n(1 min) (17.60 ± 0.14)\nL8-BO-sonicated 18.04\n26.06 0.880 78.65\nPM6:L8-BO (2 min) (17.80 ± 0.15)\n(o-XY) L8-BO-sonicated 18.18\n26.21 0.881 78.72\n(3 min) (17.97 ± 0.11)\nL8-BO-sonicated 18.08\n26.09 0.881 78.66\n(4 min) (17.79 ± 0.20)\nL8-BO-sonicated 17.99\n26.04 0.879 78.61\n(5 min) (17.71 ± 0.17)\naAverage PCEs with standard deviations determined using 10 individual devices.\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 60 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 17.65\n25.57 0.880 78.45\n(1 min) (17.39 ± 0.18)\nL8-BO-sonicated 17.71\n25.69 0.881 78.26\nPM6:L8-BO (2 min) (17.48 ± 0.19)\n(o-XY) L8-BO-sonicated 17.76\n25.83 0.880 78.13\n(3 min) (17.60 ± 0.15)\nL8-BO-sonicated 17.69\n25.84 0.877 78.06\n(4 min) (17.41 ± 0.22)\nL8-BO-sonicated 17.61\n25.78 0.876 77.98\n(5 min) (17.29 ± 0.27)\naAverage PCEs with standard deviations determined using 10 individual devices.\nSupplementary Table 12. Photovoltaic parameters of the PM6:L8-BO-based OSCs (explored\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 80 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 17.41\n25.27 0.880 78.29\n(1 min) (17.24 ± 0.13)\nL8-BO-sonicated 17.36\n25.27 0.878 78.15\nPM6:L8-BO (2 min) (17.10 ± 0.17)\n(o-XY) L8-BO-sonicated 17.28\n25.24 0.877 78.06\n(3 min) (17.09 ± 0.12)\nL8-BO-sonicated 17.14\n25.09 0.876 77.98\n(4 min) (16.89 ± 0.18)\nL8-BO-sonicated 17.05\n25.01 0.875 77.91\n(5 min) (16.77 ± 0.14)\naAverage PCEs with standard deviations determined using 10 individual devices.\nsonication conditions. a-c, J–V curves of the devices and d-f, statistics of the optimized PCEs\nwith different frequency, power, and duration.\nSupplementary Table 13. Photovoltaic parameters of the PM6:L8-BO-based OSCs (explored\nunder different sonication frequency using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(300 W, 3 min) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 18.02\n26.13 0.880 78.38\n(20 kHz) (17.89 ± 0.12)\nPM6:L8-BO L8-BO-sonicated 18.18\n26.21 0.881 78.72\n(o-XY) (40 kHz) (17.97 ± 0.11)\nL8-BO-sonicated 17.76\n25.83 0.880 78.13\n(60 kHz) (17.61 ± 0.15)\n25.24 0.877 78.06\n(80 kHz) (17.02 ± 0.21)\naAverage PCEs with standard deviations determined using 10 individual devices.\nunder different sonication power using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(40 kHz, 3 min) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 18.18\n26.21 0.881 78.72\n(300 W) (17.97 ± 0.11)\nL8-BO-sonicated 18.52\n26.59 0.879 79.24\n(430 W) (18.31 ± 0.14)\nPM6:L8-BO L8-BO-sonicated 18.79\n26.87 0.878 79.64\n(o-XY) (560 W) (18.51 ± 0.15)\nL8-BO-sonicated 19.01\n26.95 0.879 80.24\n(640 W) (18.80 ± 0.14)\nL8-BO-sonicated 19.43\n27.05 0.881 81.53\n(720 W) (19.22 ± 0.16)\nL8-BO-sonicated 19.16\n27.08 0.880 80.41\n(800 W) (18.96 ± 0.12)\naAverage PCEs with standard deviations determined using 10 individual devices.\nunder different sonication duration using o-XY) under AM 1.5G/100 mW cm−2 illumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(720 W, 40 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nL8-BO-sonicated 18.26\n26.23 0.879 79.19\n(720 W, 1 min) (17.98 ± 0.18)\nL8-BO-sonicated 19.04\n26.87 0.883 80.23\n(720 W, 2 min) (18.85 ± 0.14)\nL8-BO-sonicated 19.43\n27.05 0.881 81.53\n(720 W, 3 min) (19.22 ± 0.16)\nPM6:L8-BO L8-BO-sonicated 19.13\n27.08 0.880 80.27\n(o-XY) (720 W, 4 min) (18.96 ± 0.11)\nL8-BO-sonicated 18.96\n26.96 0.879 79.99\n(720 W, 5 min) (18.75 ± 0.13)\nL8-BO-sonicated 18.72\n26.61 0.882 79.76\n(720 W, 6 min) (18.53± 0.12)\nL8-BO-sonicated 18.53\n26.44 0.880 79.65\n(720 W, 7 min) (18.35 ± 0.15)\nL8-BO-sonicated 18.24\n26.22 0.876 79.41\n(720 W, 8 min) (18.06 ± 0.12)\naAverage PCEs with standard deviations determined using 10 individual devices.\n37\n(b) Consideration of solution temperature variations during sonication,\nResponse: We appreciate the reviewer for the constructive comment. Following the reviewer’s\nsuggestion, we have monitored solution temperature variations during the process of ultrasonic\nprocessing. Results are shown in Figure R14 (Supplementary Fig. 7). The related video is\npresented as an additional Supplementary file. It can be clearly seen that the temperature of the\nsolution slightly increases from 24.1 ℃ to 26.2 ℃ (from 297.1 K to 299.2 K) throughout the\nsonication process. This suggests that the temperature increase resulting from sonication can be\ndisregarded in practical applications.\nFigure R14 (Supplementary Fig. 7) Temperature changes of solution during sonication.\nTemperature of the L8-BO solution after different time of sonication.\n(c) The rationale for using 300 W in Figure S3 while designating 720 W as optimal,\nResponse: We thank the reviewer for pointing out this issue and the constructive comment. We\napologize for the lack of clarity in our previous description of the sonication power effects.\nWe have provided a detailed analysis about the impact of sonication power on device performance\n(see response to your comment 1a) and molecular aggregation behaviors in the L8-BO solution\nby performing in-situ PL measurements. Results are shown in Figure R6 (Supplementary Fig.\n3) in the revised SI. Both device data and PL spectra have confirmed that the optimal sonication\npower is 720 W.\nBO solution during sonication with different power (frequency: 40 kHz).\n(d) The unaddressed influence of sonication time on the molecular aggregation process.\nResponse: We thank the reviewer for the constructive comment. We have studied the influence\nof sonication time on the molecular aggregation process in the L8-BO solution by performing\nin-situ PL measurements. Results are shown in Figure R7 (Supplementary Fig. 4) in the\nrevised SI. With the increase of sonication time, the PL spectra present a continuous redshift.\nThis demonstrates the continuous enhancement of molecular aggregation. Combined with the\ndevice data, it can be found that excessive molecular aggregation is detrimental to the\nphotovoltaic performance.\nBO solution during sonication with different duration (frequency: 40 kHz, power: 720 W).\nOn Page 1 in the revised SI, we have added relevant descriptions of the optimal conditions of\nsonication as follows:\n“To determine the optimal sonication parameters, we have systematically studied the effects of\nfrequency, power, and duration on molecular aggregation and photovoltaic performance by\nperforming in-situ PL measurements and fabricating organic solar cells (OSCs). We first fixed\nthe power in order to identify the optimal frequency and duration. Subsequently, the frequency\nand duration were held constant to determine the optimal power. Finally, the frequency and\npower were maintained to confirm the optimal duration. The in-situ PL spectra of the L8-BO\nsolution are displayed in Supplementary Fig. 2-4. Sonication is usually accompanied by\nphysical and chemical effects. As the frequency increases, the physical mechanical gradually\nweakens. When the frequency is 20 kHz, the relatively large shear stress can destroy the\naggregation, while the frequency above 40 kHz, the shear stress is too small to drive the\nformation of J-aggregation. Therefore, the redshift of the PL spectrum first increases and then\ndecreases. As the sonication power increases, the effects of shear stress become increasingly\nstrong. Once the effect reaches a certain intensity, it further causes molecular slippage,\ndisrupting the original J-aggregation, thereby reducing the degree of redshift. According to\nquantitative analysis of the redshift degree of PL spectra (Supplementary Fig. 5), it can be\nconcluded that the optimal frequency (40 kHz) and power (720 W) play an obvious role in\npromoting the formation of J-aggregation. In addition, with the increase of sonication time, the\ncontinues to enhance as long as the shear stress remains constant. Device data are shown in\nSupplementary Fig. 31-32 and Table 9-15. The optimal conditions of sonication are determined\nto be 40 kHz, 720 W, and 3 min. Combined with in-situ PL data, it can be concluded that\nexcessive molecular aggregation is detrimental to device performance”\n2. The comparative analysis of device performance parameters in binary blends before and after\nsonication reveals enhanced open-circuit voltage (V ). Given the authors' emphasis on\nOC\nultrasound-induced suppression of molecular vibrations and reduced non-radiative\nrecombination, it is recommended to provide detailed energy loss quantification to substantiate\nthe role of ultrasonic treatment in minimizing voltage losses.\nResponse: We thank the reviewer for the constructive comment. We have studied the energy\nloss by measuring the electroluminescence (EL) spectra, external quantum efficiency (EQE) of\nEL (EQE ), and sensitive EQE (sEQE) from Fourier transform photocurrent spectroscopy\nEL\n(FTPS-EQE). Results are shown in Figure R15 (Supplementary Fig. 41) and Table 26 in the\nrevised SI. The bandgap of devices (E ) is determined from the intersection of the normalized\ng\nEL and sensitive EQE spectra [Adv. Mater. 2025, 37, 2500357; Nat. Mater. 2018, 17, 703–709].\nThe detailed energy loss analysis has been added in the revised SI. It is concluded that ultrasonic\nprocessing slightly suppresses the non-radiative recombination loss (ΔE ).\n“Energy loss was evaluated based on the measurements of the electroluminescence (EL) spectra,\nthe external quantum efficiency of electroluminescence (EQE ), and the sensitive external\nEL\nquantum efficiency (sEQE) measured by Fourier transform photocurrent spectroscopy (FTPS-\nEQE) (Supplementary Fig. 41 and Supplementary Table. 26). It was concluded that sonication\nslightly suppressed the energy loss, especially non-radiative recombination loss ΔE (from\n3\n0.243 eV to 0.239 eV). Meanwhile, the extracted Urbach energy decreased from 24.16 meV to\n23.57 meV, suggesting a concomitant reduction in energy disorder70, which is aligned with the\ndecrease of radiative recombination loss ΔE (from 0.076 eV to 0.074 eV).”\n2\nas follows:\n“Calculation of energy loss\nThe energy loss (E ) in OSCs can be determined from the difference between the optical\nloss\nbandgap (E ) and the open-circuit voltage (V ), which is divided into three main components\ng OC\naccording to the following equation:\n𝐸 = 𝐸 −𝑞𝑉 = (𝐸 −𝑞𝑉 𝑆𝑄 )+(𝑞𝑉 𝑆𝑄 −𝑞𝑉𝑟𝑎𝑑)+(𝑞𝑉𝑟𝑎𝑑 −𝑞𝑉 )\n𝑙𝑜𝑠𝑠 𝑔 𝑂𝐶 𝑔 𝑂𝐶 𝑂𝐶 𝑂𝐶 𝑂𝐶 𝑂𝐶 𝑂𝐶\n= 𝛥𝐸 +𝛥𝐸 +𝛥𝐸 (28)\n1 2 3\nwhere 𝑉 𝑆𝑄 is the thermodynamic limit of V in the Shockley-Queisser (SQ), 𝑉𝑟𝑎𝑑 is the V\n𝑂𝐶 OC 𝑂𝐶 OC\nwhen only considering radiative recombination with realistic absorption edges. ΔE represents\n1\n𝑆𝑄\nthe radiative recombination loss above the bandgap (𝛥𝐸 = 𝐸 −𝑞𝑉 ), which is a commonly\n1 𝑔 𝑂𝐶\nunavoidable part for any type of solar cells. ΔE represents the radiative recombination loss\n2\nbelow the bandgap (𝛥𝐸 = 𝑞𝑉 𝑆𝑄 −𝑞𝑉𝑟𝑎𝑑), which is related to the degree of energy disorder\n2 𝑂𝐶 𝑂𝐶\nand reorganization. ΔE is the nonradiative recombination loss (𝛥𝐸 = 𝑞𝑉𝑟𝑎𝑑 −𝑞𝑉 ), which\n3 3 𝑂𝐶 𝑂𝐶\nis calculated from the luminescence efficiency of photovoltaic materials given as follows:\n𝛥𝐸 = −𝑘 𝑇𝑙𝑛(𝐸𝑄𝐸 ) (29)\n3 𝐵 𝐸𝐿\nwhere k is the Boltzmann constant. EQE is the electroluminescence (EL) quantum efficiency\nB EL\nof the actual devices.”\ndevices without and with sonication. a-b, Normalized sEQE and EL spectra, and c-d, detailed\nEQE and E values of the PM6:L8-BO-based devices without and with sonication.\nEL loss\nSupplementary Table 26. Key parameters for energy loss of the PM6:L8-BO-based devices\nwithout and with sonication.\nActive layer E (eV) qV (eV) E (eV) ΔE (eV) ΔE (eV) EQE (%) ΔE (eV)\ng OC loss 1 2 EL 3\nControl 1.466 0.878 0.588 0.269 0.076 0.82×10−2 0.243\nSonicated 1.463 0.881 0.582 0.269 0.074 0.93×10−2 0.239\n43\n3. As shown in Figure 2h−i, the control device exhibits excessively large phase domains\n(acceptor: 50−70 nm; donor: 50−100 nm), significantly exceeding the reported exciton\ndiffusion length (29.66 nm, Supplementary Table 7). The apparent contradiction between this\nmorphology and the high PCE of 17.8% requires clarification.\nResponse: We thank the reviewer for pointing out this issue and the constructive comment. We\napologize for the previous misleading presentation about phase domains in Fig. 2h-i in the\noriginal manuscript. Following the reviewer’s suggestion, we have made revisions accordingly.\nResults are shown in Figure R16 (Fig. 2h-i) in the revised manuscript. After sonication, the\nacceptor domains in blend films exhibited fibrillar structures with an approximate diameter of\n23 nm. The increase in the amount of small fibril structures indicated the formation of a fibril\nnetwork between the donor and acceptor phases.\nFigure R16 (Fig. 2) Morphological analysis of blend films. h-i, The line profiles recorded\nalong the white arrows to obtain the fibril width for the PM6:L8-BO blend films without and\nwith sonication.\n4. The author mentioned on page 12: \"which indicated that sonication facilitated exciton\ndelocalization. It can effectively reduce the dependence of exciton dissociation on the D/A\ninterface.\" Please cite relevant literature for proof.\nResponse: We thank the reviewer for the constructive comment. The relevant literature have\nbeen cited and provided in the revised manuscript [J. Am. Chem. Soc. 2020, 142, 12751-12759;\nNat. Energy 2022, 7, 1076-1086; Sci. Adv. 2025, 11, eadt6024].\n“After sonication, the contribution of the pathway dominated by i-DE states substantially\nincreased (0.54 → 0.6), which indicated that the resulting morphology in the sonicated films\nfacilitate exciton delocalization. It can effectively reduce the dependence of exciton dissociation\non the D/A interface55–57.”\n55. Wang, R. et al. Charge separation from an intra-moiety intermediate state in the high-\nperformance PM6:Y6 organic photovoltaic blend. J. Am. Chem. Soc. 142, 12751–12759\n(2020).\n56. Jiang, K. et al. Suppressed recombination loss in organic photovoltaics adopting a planar–\nmixed heterojunction architecture. Nat Energy 7, 1076–1086 (2022).\n57. Xu, R. et al. Enhancing singlet excitons delocalization via selective asymmetric\nfluorination of electron acceptors for efficient organic solar cells. Sci. Adv. 11, eadt6024\n(2025).\n5. Generally, more ordered molecular packing reduces heat generation from molecular\nvibrations. As noted on page 15 of the manuscript, “sonication-induced structural tuning with\nordered J-aggregate geometry allows for rapid thermal energy re-distribution and\ndissipation···”. Relevant literature should be cited to support this claim.\nResponse: We thank the reviewer for the constructive comment. The relevant literature have\nbeen cited and provided in the revised manuscript [Adv. Mater. 2020, 32, 2003164].\nOn Page 15 in the revised manuscript, we have added relevant literature as follows:\n“As discussed previously, sonication-induced structural tuning with ordered J-aggregate\ngeometry allows for rapid thermal energy re-distribution and dissipation64, which deactivates\nthe thermally-activated non-radiative recombination of excitons.”\n64. Guo, Q. et al. Enhancing the performance of organic solar cells by prolonging the lifetime\nof photogenerated excitons. Adv. Mater. 32, 2003164 (2020).\n45\n6. The manuscript indicates that the sonicated L8-BO film promotes intra-moisty delocalized\nexciton (i-DE) generation while simultaneously exhibiting extended exciton diffusion length.\nHowever, the text primarily emphasizes enhanced exciton delocalization. Can the individual\ncontributions of these two effects be quantitatively distinguished?\nResponse: We thank the reviewer for the constructive comment. As indicated in the original\nmanuscript, a global fitting model for TAS data was developed to quantify the spectral and\ndynamic information of two exciton dissociation pathways (LE→i-DE→CS; LE→CT→CS).\nGlobal fitting results reveal that the contribution of the i-DE-mediated pathway increases from\n0.54 to 0.60, which can be quantitatively expressed as exciton delocalization enhancement,\nwhile the contribution of the charge-transfer-mediated pathway decreases from 0.46 to 0.40\nafter sonication. Moreover, all lifetimes associated with two exciton dissociation pathways are\nreduced after sonication, indicating enhanced charge separation in both channels. Critically, the\nreinforced CT-mediated pathway is attributed to the enhancement of the exciton diffusion\nlength, which is consistent with the increase in exciton diffusion length calculated quantitatively\nin the original manuscript.\n7. While sonication treatment of the acceptor solution enhances exciton dissociation and\nreduces nonradiative recombination, does it also can promote ordered stacking in the donor\nmaterial? Additionally, considering the complexity of layer-by-layer processing, is this method\ndirectly applicable to donor-acceptor blend solutions?\nResponse: We thank the reviewer for the constructive comments. As indicated in the original\nmanuscript, we present research focused exclusively on the sonication of the acceptor solution.\nActually, the effects of sonication on the PM6 solution for layer-by-layer (LBL) fabrication and\nthe PM6:L8-BO blend solution for bulk-heterojunction (BHJ) fabrication were also studied in\nthe initial research of this work. The PL spectra and device data associated with the sonication\nof the PM6 solution are shown in Figure R17 (Supplementary Fig. 8b, 33c) and Table 18 in\nthe revised SI. A slight blueshift is observed in the PL spectra during sonication. The\ncorresponding LBL-type OSCs exhibit slightly lower PCEs than that of the control devices.\nof PM6 and improve device performance.\nFigure R17 (Supplementary Fig. 8b and 33c) The analysis of the PM6-sonicated devices.\na, Evolution of the PL spectra of the PM6 solution during sonication (frequency: 40 kHz, power:\nSupplementary Table 18. Photovoltaic parameters of the PM6-sonicated:L8-BO-based OSCs\n(explored under different sonication duration using o-XY) under AM 1.5G/100 mW cm−2\nillumination.\nCondition J V FF PCEa\nSC OC\nActive layer\n(720 W, 40 kHz) (mA cm-2) (V) (%) (%)\n17.50\nAs cast 25.36 0.878 78.56\n(17.28 ± 0.19)\nPM6-sonciated 17.33\n25.23 0.875 78.51\nPM6:L8-BO (1 min) (17.18 ± 0.14)\n(o-XY) PM6-sonciated 17.24\n25.21 0.875 78.14\n(3 min) (16.91 ± 0.28)\nPM6-sonciated 17.01\n24.91 0.876 77.95\n(5 min) (16.67 ± 0.23)\naAverage PCEs with standard deviations determined using 10 individual devices.\nThe PL spectra and device data associated with sonication of the PM6:L8-BO blend solution\nare displayed in Figure R18 (Supplementary Fig. 8c, 33d) and Table 19 in the revised SI.\nThe PL spectra exhibit a continuous redshift in the L8-BO emission region. The corresponding\nBHJ-type OSCs with sonication show a higher PCE (19.16%) than that (17.39%) of the control\ndevices. This demonstrates that the sonication method can be directly applicable to the donor-\nacceptor blend solution. Furthermore, based on the results of device data, sonication presents\nan obvious role in modulating molecular aggregation in the neat L8-BO solution relative to the\nPM6:L8-BO blend solution.\nof the PL spectra for the PM6:L8-BO blend solution during sonication (frequency: 40 kHz,\npower: 720 W). b, J-V curves of the BHJ-type devices without and with sonication.\nSupplementary Table 19. Photovoltaic parameters of the PM6:L8-BO-based BHJ-type OSCs\nwithout and with sonication.\nCondition (720 W, 40 J V FF PCEa\nSC OC\nActive layer\nkHz, 3 min) (mA cm-2) (V) (%) (%)\n17.39\nw/o 25.14 0.882 78.43\nPM6:L8-BO (17.10 ± 0.18)\n(o-XY) 19.28\nsonicated 27.35 0.879 80.18\n(19.14 ± 0.12)\naAverage PCEs with standard deviations determined using 10 individual devices.\nOn Page 3 in the revised SI, we have added relevant descriptions as follows:\n“The effects of sonication on the PM6 solution for layer-by-layer (LBL) fabrication and the\nPM6:L8-BO blend solution for bulk-heterojunction (BHJ) fabrication have been investigated\nby performing in-situ PL measurements and fabricating OSCs. A slight blue shift is observed\nin the PL spectra during the sonication process of the PM6 solution (Supplementary Fig. 8b).\nThe corresponding LBL-type OSCs exhibit the lower PCEs than that of the control devices\n(Supplementary Fig. 33c and Table 18). These results demonstrate that sonication of the PM6\nsolution does not promote ordered stacking of PM6 and improve device performance. The in-\nsitu PL spectra and device results associated with sonication of the PM6:L8-BO blend solution\nare displayed in Supplementary Fig. 8c and 33d, and Table 19. The PL spectra exhibit a\ncontinuous red shift in the L8-BO emission region. The corresponding BHJ-type OSCs with\nsonication show a higher PCE (19.28%) than that (17.39%) of the control devices. This\ndemonstrates that sonication can be directly applicable to the donor-acceptor blend solution.\nMoreover, it can be concluded that sonication presents an obvious role in modulating molecular\naggregation in the L8-BO solution relative to the PM6:L8-BO blend solution.”\nThe manuscript by Zhou and coworkers reports an interesting method based on sonication to\ninduce J-aggregation in non-fullerene-based solar cells processed in non-chlorinated solvents.\nThis results in PCE exceeding 80% due to a combination of enhanced FF, resulting from the\nimproved microstructure, and J , resulting from enhanced light-to-current conversion, as\nSC\ndemonstrated by ultra-fast spectroscopy measurements. Moreover, the authors demonstrated\nthe universality of this approach with a variety of blend systems (and ternary). Overall, this is\nan interesting work, which should be considered in Nature Communications. However, I\nsuggest the following comments/additions before proceeding further.\nResponse: We thank the reviewer for the positive comments on this work and recommending\nits publication after some revisions.\n1) The morphological analyses are based on GIWAXS data. However, the quality of the 2D\nplots is quite poor, making it difficult to fully appreciate the line cut (1D) and therefore the\nrelative analyses. I suggest performing higher-quality measurements and extracting the relevant\nparameters based on the new images.\nResponse: We thank the reviewer for the constructive comment. We have performed higher-\nquality GIWAXS measurements (Shanghai Synchrotron Radiation Facility, beamline: BL16B1)\non neat and blend films, and extracted the relevant parameters from the new 2D patterns. Results\nare shown in Figure R19-21 (Figs. 1h-i, 2a-c, Supplementary Fig. 17) and Supplementary\nTables 2-3.\ncalculations and experiments. h–i, Two-dimensional (2D) grazing-incidence wide-angle X-\nray scattering (GIWAXS) patterns of the L8-BO films obtained without and with sonication.\nFigure R20 (Supplementary Fig. 17) GIWAXS measurements of neat films. OOP (out-of-\nplane) and IP (in-plane) extracted line-cut profiles of neat L8-BO films obtained without and\nwith sonication.\nSupplementary Table 2. Summary of GIWAXS π-π stacking information in the OOP direction\nfor neat L8-BO films obtained without and with sonication.\nActive layer q (Å-1) d-spacing (Å) FWHM (Å-1) CCL (Å)\nL8-BO 1.753 3.584 0.241 23.46\nL8-BO-sonicated 1.769 3.552 0.225 25.13\nfresh PM6:L8-BO (o-XY) blend films obtained without and with sonication. c, Out-of-plane\nand in-plane extracted line-cut profiles of the corresponding films.\nSupplementary Table 3. Summary of GIWAXS π-π stacking information in the OOP direction\nfor fresh PM6:L8-BO blend films obtained without and with sonication.\nActive layer (Fresh) q (Å-1) d-spacing (Å) FWHM (Å-1) CCL (Å)\nControl 1.751 3.588 0.231 24.48\nSonicated 1.770 3.550 0.207 27.32\nOn Page 6 in the revised manuscript, we have rewritten relevant descriptions as follows:\n“This effect was quantitatively assessed using grazing-incidence wide-angle X-ray scattering\n(GIWAXS) measurements (Figs. 1h and i, Supplementary Fig. 17, and Supplementary Table\n2). Prominent - stacking peaks of the control (1.753 Å) and sonicated (1.769 Å) L8-BO films\nwere observed in the out-of-plane (OOP) direction45. The decrease in d-spacing from 3.584 Å\nto 3.552 Å after sonication indicated a closer intermolecular packing. The calculated crystal\ncoherence length (CCL) increased from 23.46 Å in the control film to 25.13 Å in the sonicated\nfilm. Thus, the sonicated L8-BO film exhibited a higher crystallinity and more ordered\nmolecular stacking than its nonsonicated counterpart. Time-resolved photoluminescence\n(TRPL) measurements revealed that sonication increased the exciton lifetime of the L8-BO film\nfrom 471 ps to 641 ps, possibly by favoring ordered J-aggregation46.”\n“Sonicated L8-BO was combined with PM6 via sequential deposition to construct layer-by-\nlayer (LBL)-type devices and thus assess the role of sonication in determining blend film\nmorphology. According to the corresponding two-dimensional (2D) GIWAXS patterns (Figs.\n2a and b), both PM6 and L8-BO exhibited a preferential face-on orientation in blend films,\nwhich favored charge transport, as evidenced by prominent (100) lamellar stacking peaks in the\nin-plane (IP) direction and strong (010) - stacking peaks in the OOP direction. After\nsonication, the CCL of the blend films increased from 24.48 Å to 27.32 Å, and the d-spacing\ndecreased from 3.588 Å to 3.550 Å (Fig. 2c and Supplementary Table 3). These results\nsuggested that sonication facilitated crystallization and ordered molecular stacking within the\nactive layers.”\n2) Figure 5b shows the EQE plots of sonicated and control devices. According to the previous\ndata, the L8BO absorption peak is shifted due to J-aggregation; however, this is not evident in\nthe EQE plot. The authors should comment on this. In addition, EQE approaching 90% should\nalways be paired with IQE measurements.\nResponse: We thank the reviewer for pointing out this issue and the constructive comment. In\norder to intuitively show the redshift of the EQE spectra, we performed a local magnification\nof EQE spectra, as shown in Figure R22 (Supplementary Fig. 34a). A relatively small redshift\nphenomenon can be observed. Meanwhile, we measured and calculated the IQE data using an\nintegrating sphere [Nat. Mater. 2022, 21, 656–663], and results are shown in Figure R22\n(Supplementary Fig. 34b). Similar to EQE plots, the IQE data of devices were also improved\nafter sonication, indicating that external parameters, such as reflection and transmission, are not\nthe limiting factors here.\nmagnification of EQE spectra. b, IQE, EQE and reflectance curves of the PM6:L8-BO-based\ndevices without and with sonication.\n3) An in-depth investigation of the degradation processes should be reported. As it stands, the\nresults, albeit interesting, are phenomenological without providing any further insight into why\nthe sonicated samples are more stable than the controls.\nResponse: We appreciate the reviewer for the constructive comment. Following the reviewer’s\nsuggestion, the normalized photovoltaic parameters (V , J , FF) as a function of aging time\nOC SC\nfor the PM6:L8-BO-based devices have been provided in Figure R23 (Supplementary Fig.\n42) in the revised SI. As for the control devices, the V and J remain relatively stable, while\nOC SC\nthe FF shows an obvious decrease. This suggests degradation primarily occurred in the mixed\namorphous region [Adv. Mater. 2020, 32, 1908305; Nat. Commun. 2023, 14, 2688]. In contrast,\nthe sonicated devices show relatively robust FF. To elucidate the potential mechanism by which\nsonication enhances morphological stability, we have performed a thermodynamic analysis of\nneat L8-BO films and PM6:L8-BO blend films by determining the glass transition temperature\n(T ). Results are shown in Figure R10-11 (Supplementary Figs. 44-45) in the revised SI. The\ng\nsonicated films present the enlarged T relative to the control samples. According to the Ade-\ng\nO’Connor-Ghasemi stability framework, this demonstrates that sonication can decrease\ndiffusion coefficients of materials and increase kinetic stabilization of film morphology [Joule\n54\n2021, 5, 2129-2147; Nat. Mater. 2021, 20, 525-532]. Hence, it can be concluded that the\nsonicated L8-BO in PM6:L8-BO blends exhibits suppressed kinetic aggregation, which is\nbeneficial for achieving stable active layer morphology on the crystalline and amorphous\nregions [Adv. Mater. 2020, 32, 1908305; Nat. Commun. 2023, 14, 2688].\nFigure R23 (Supplementary Fig. 42) The analysis of device stability. Normalized V , J\nOC SC\nand FF decay traces of the PM6:L8-BO-based devices without and with sonication during a–c,\nthermal stability evaluation at 80 °C and d–f, photothermal stability evaluation under\ncontinuous illumination (100 mW cm−2, white light-emitting diode) at 50–60 °C.\ntemperature. Evolution of UV-vis deviation metric as a function of annealing temperature of\nthe L8-BO films a-b, without and c-d, with sonication.\ntemperature. Evolution of UV-vis deviation metric as a function of annealing temperature of\nthe PM6:L8-BO blend films a-b, without and c-d, with sonication.\nFollowing the reviewer’s suggestion, we have also conducted an investigation of the crystalline\nphase in the aged PM6:L8-BO blend films (thermal annealing at 80 ℃ for 200 h in a N -filled\n2\nglove box) by performing GIWAXS measurements. Results are shown in Figure R21\n(Supplementary Fig. 43) and Supplementary Table 27 in the revised SI. After continuous\nthermal aging for 200 h, the CCLs of the sonicated films decreased slightly from 27.32 Å to\n26.93 Å, exhibiting better stability in crystalline regions than the control samples (from 24.48\nÅ to 23.08 Å).\nfresh PM6:L8-BO (o-XY) blend films obtained without and with sonication. c, Out-of-plane\nand in-plane extracted line-cut profiles of the corresponding films.\nSupplementary Table 3. Summary of GIWAXS π-π stacking information in the OOP direction\nfor fresh PM6:L8-BO blend films obtained without and with sonication.\nActive layer (Fresh) q (Å-1) d-spacing (Å) FWHM (Å-1) CCL (Å)\nControl 1.751 3.588 0.231 24.48\nSonicated 1.770 3.550 0.207 27.32\nFigure R24 (Supplementary Fig. 43) GIWAXS measurements of aged films. a–b, 2D\nGIWAXS patterns of aged PM6:L8-BO (o-XY) blend films (thermal annealing at 80 ℃ for 200\nh in a N -filled glove box) obtained without and with sonication. c, Out-of-plane and in-plane\n2\nextracted line-cut profiles of the corresponding films.\nSupplementary Table 27. Summary of GIWAXS π-π stacking information in the OOP\ndirection for aged PM6:L8-BO blend films obtained without and with sonication.\nActive layer (Aged) q (Å-1) d-spacing (Å) FWHM (Å-1) CCL (Å)\nControl 1.746 3.599 0.245 23.08\nSonicated 1.768 3.554 0.210 26.93\n“To elucidate the mechanism by which sonication improves morphological stability, we\nextracted the normalized photovoltaic parameters (V , J and FF) over aging time for\nOC SC\nPM6:L8-BO-based devices, as shown in Supplementary Fig. 42. The control devices remained\nrelatively stable V and J , whereas FF showed a marked decline. In contrast, the sonicated\nOC SC\ndevices exhibited robust FF, indicating that sonication could suppress the degradation in mixed\namorphous regions71,72. Additionally, the sonicated films showed slight attenuation of CCL\nvalues (from 27.32 Å to 26.93 Å) after continuous thermal aging for 200 h compared to that\n(from 24.48 Å to 23.08 Å) of controls (Supplementary Fig. 43 and Supplementary Table. 27),\nsuggesting the better stability in crystalline regions. Further thermodynamic analysis was\nconducted on neat L8-BO films and PM6:L8-BO blend films through the glass transition\ntemperature (T ) measurements (Supplementary Figs. 44 and 45). The sonicated samples\ng\ndisplayed higher T than the controls, indicating that sonication reduced the diffusion\ng\ncoefficient of material in mixed amorphous region and enhanced the kinetic stabilization of film\nmorphology9,73. The results demonstrate the advantages of the sonication-improved active layer\nmorphology for improving device stability.”\n4) Figure 3g shows the dynamics of each component of the exciton to charge conversion, with\nthe sonicated samples featuring longer CS, however, in Figure 4d (TRIR) the sonicated samples\nare now shorter-lived (in the same time scale). The authors should comment on that.\nResponse: We thank the reviewer for pointing out this issue and the constructive comment. Fig.\n4d presents the decay of the positive ESA signals at 1485 cm-1 in TRIR. This signal is only\nslightly downshifted compared to the GSB features. It is most likely attributed to the frequency\nshift due to laser-induced local heating, which produces hot S and LE instantaneously upon\n0\nexcitation. We have ruled out the possibility that this signal (Fig. 4d) is associated with the\nformation of the CT/CS states with the following rationale: unlike the smooth-varying\nbackground polaron signal (Fig. 4b) that shows growth on picosecond timescale and decay on\nnanosecond timescale corresponding to the CT/CS kinetics observed in TAS data, this positive\nfeature in Fig. 4d does not show any growth throughout the scan window and mostly decays\n59\nwithin 10 ps (a reasonable timescale for vibrational relaxation for such blend systems)\n[Energy Environ. Sci. 2023, 16, 2945-2956]. Therefore, we have used the feature in Fig. 4d to interpret\nhow excess heat/vibrational energy dissipates in these blend systems. In contrast, the broad\nbackground feature in Fig. 4a has been used to track the dynamics of the CT/CS states such as\nFig. 4b, which is related to the dynamics obtained from TAS data (Fig. 3g).\n60"}, {"round": 2, "reviewer_comments": {"reviewer_1": "The authors have provided substantial additional experimental data and made extensive revisions to the original text. The manuscript is now suitable for acceptance in Nature Communications.", "reviewer_2": "The authors have addressed the issues raised by this reviewer. The manuscript is now suitable for publication in Nature Communications.", "reviewer_3": "The authors replied to all my comments and those of other reviewers with additional data and analyses. I suggest publishing this manuscript in Nature Communications without any further delays."}, "author_response": ""}]

Decision letter