Dimensional control of low-dimensional perovskite hybrids for photovoltaics

Domain: chemistry
Published: 2026-04-13
Editorial outcome: minor_revision

Abstract
Low-dimensional perovskite engineering offers a promising route to improve both power
conversion efficiency and stability in perovskite photovoltaics, yet the mechanistic relationship
between organic ligand design and structural control remains elusive. Here, we report a molecular
design strategy for bis-imidazolium ligands that enables precise dimensional tuning of perovskite
architectures, from zero-dimensional through parallel one-dimensional to bridged zero-
dimensional configurations. Through systematic variation of terminal groups and inter-imidazole
spacing, we achieve controlled growth of high-quality hybrid dimensional perovskite films with
optimized crystallization kinetics and charge transport properties. This enables photovoltaic
devices with a certified power conversion efficiency of 27.02% (laboratory 27.21%). Scaling this
dimensional strategy enables the fabrication of 30×30 cm2 perovskite solar modules, achieving a
champion power conversion efficiency of 21 .41% Moreover, unencapsulated devices retain 94.3%
of their initial power conversion efficiency after 2,000 hours of continuous operation at 60 °C
(ISOS-L-2I), highlighting exceptional operational stability.

Introduction
Perovskite photovoltaics have achieved power conversion efficiencies (PCEs) exceeding 27%,
rivaling established photovoltaic technologies1–3, while the operational instability remains a
critical barrier to commercialisation4–6. Integration of low-dimensional perovskites and three-
dimensional (3D) represents a compelling solution, offering enhanced stability compared to their
3D counterparts7–12 by simultaneously passivating defects (on both surface and grain boundaries)
and forming favorable heterojunctions with 3D phases13–15. Recent works showed promising
features of low-dimensional perovskite in improving charge extraction, optimizing band alignment
and boosting operational stability16–20.

Organic cations have been used to tailor the dimensionality of two-dimensional (2D) perovskite
passivation layers for enhancing the photovoltaic performance of perovskite solar cells (PSCs)17,21.
At the atomic level, the organic cations usually form an insulating layer that impedes the out-of-
plane charge transportation between perovskite layers degrading the PCE22; and the heterogeneous
dimensionality of the 2D perovskite layers is detrimental for charge carrier dynamics23. The
strategic development of zero-dimensional (0D) and one-dimensional (1D) perovskites effectively
circumvents these issues in constructing high-performance photovoltaic devices, because they
prevent the insulation layer and improve the homogeneity of perovskite.

Current strategies of growing 0D and 1D perovskite has focused on the selection of cationic ligands
in a trial-and-error fashion. The reported functioning ligands24,25 are rather limited, due to laborious
and challenging experimental characterization of ligand-induced low-dimensional phases21,26.
Previous studies demonstrated that mono-imidazolium-based ionic liquids can form low-
dimensional perovskite by coordinating with lead iodide (PbI ), which enabled the fabrication of
2
highly efficient and stable low-dimensional/3D hybrid perovskite solar cells27,28. Dual cationic
ligands in principle features enhanced coordination with PbI to reinforce the structural integrity
2
of lead-halide octahedral frameworks. However, fundamental understanding of how dual cationic
ligands control the perovskite dimensionality, in particularly 0D and 1D, remains far less
developed.

Here, we present a precise control of the perovskite dimensionality from 0D molecular crystals to
parallel 1D, and ultimately bridged 1D architectures through systematic engineering of dual
cationic imidazole ligands. By modulating inter-imidazole spacing and terminal functional groups,
we establish clear structure-dimensionality relationships, validated by single crystal X-ray
diffraction (XRD) and computational analysis. Specifically, our precise modification of ligands
successfully creates highly oriented 1D perovskites stacked with bulk phase, yielding enhanced
charge carriers transport in 1D–3D hybrid films. We further demonstrate that the 1D–3D
heterointerface exhibit uniform surface potential and reduced work function, achieving a record
PCE of 27.21% (a certified PCE of 27.02%) in 1D/3D perovskite solar cells. The dimensional
strategy is successfully scaled to 30×30 cm2 perovskite modules, yielding a champion PCE of
21.41%. The unencapsulated devices retain 94.3% of their initial PCE after 2,000 hours maximum
power point tracking under continuous AM 1.5 G illumination at 60 °C, demonstrating exceptional
stability.

Results
Structural analysis of ligands and their single-crystals
We designed four modulated dual-imidazolium ligands (Dim-C2-CH , Dim-C2-OMe,
3
Dim-C2-CN and Dim-C4-CN) to explore the correlation between ligand structures and the dimensionality
of novel low-dimensional perovskite phases (Fig. 1a and Supplementary Figs. 1-8). To investigate
the energetically favorable configurations of the dual-imidazolium ligands in Dimethyl sulfoxide
(DMSO), density functional theory (DFT) calculations were conducted (Supplementary Figs. 9-
12). Comparative analysis of their lowest-energy configurations revealed that polar groups reduce
the terminal distance due to electrostatic attraction to the imidazole rings (CH
3
: 5.90 Å > OMe: 4.96 Å > CN: 4.09 Å), while increasing the carbon spacer between the imidazole rings extends the
inter-imidazolium distance (Fig. 1b). In particular, Dim-C2-CH , Dim-C2-OMe, and Dim-C2-CN
3
exhibit inter-imidazolium distances of 4.70 Å, 4.78 Å, and 4.76 Å respectively, closely matching
the 4.05 Å periodicity of [PbI ]− motifs. Dim-C4-CN has an extended inter-imidazolium distance
3
(8.79 Å), capable to bridge two [PbI ]− motifs. The DFT optimizations of Dim-C2-CH with a 1D
3 3
PbI cluster show a broken chain architecture, indicating a 0D perovskite structure (Supplementary
2
Fig. 13). Dim-C2-CN and Dim-C4-CN showed suitable alignment with the [PbI ]− motifs,
3
suggesting the formation of 1D perovskite.

We synthesized high-quality single crystals through controlled co-crystallization of PbI with each
2
tailored ligand to validate the proposed low-dimensional perovskite. Optical microscopy and XRD
analysis of organic ligands and single crystals confirmed high crystallinity across all four systems,
with experimental patterns in excellent agreement with simulated diffractions (Supplementary Figs.
14-16). As predicted by DFT calculations, we obtained a 0D perovskite crystal (space group R-3,
Supplementary Tables 1-8) using the Dim-C2-CH ligand, formulated as (Dim-C2-
3
CH ) Pb I Br (Fig. 1c, d and Supplementary Fig. 13). XRD confirmed the predicted linear
3 3 3 4.9 7.1
terminal configurations of Dim-C2-CH (5.79 Å). The ligands with methoxy groups (Dim-C2-
3
OMe) and cyano groups (Dim-C2-CN) both yield a 1D perovskite crystal Dim-C2-OMe(PbI )
3 2
(Supplementary Tables 9-16) and Dim-C2-CN(PbI ) (Supplementary Tables 17-24), where the
3 2
terminal distances reduced to 4.90 and 4.06 Å (Fig. 1c), respectively in line with the DFT results.
Moreover, the DFT calculations show an isostructural 1D perovskite crystal when replacing the
cyano (CN) groups with oxhydryl (OH) groups (Supplementary Figs. 17-18) and the CN groups
(-6.07 eV) showed larger crystal formation energy than the CH (-5.35 eV) and OH (-5.63 eV)
3
groups.

Extending inter-imidazolium chain length from Dim-C2-CN scaffold to Dim-C4-CN transformed
the parallel 1D orientation to a bridged 1D architecture (Fig. 1d), Dim-C4-CN(PbI
3
) ,
2
which is
classified within the monoclinic crystal (space group P 21/c. Supplementary Tables 25-31). This
configuration enhances interchain connectivity via ligand-mediated bridging, markedly stabilizing
the perovskite framework. DFT calculations show that further substitution of CN groups (-6.71
eV) with CH (-6.28 eV) or -OH (-6.43 eV) groups reduced the crystal formation
3
energy(Supplementary Figs. S19-20). The formation energy of Dim-C4-CN (PbI
3
) 
2
(-6.71 eV) is
lower than that of Dim-C2-CN (PbI ) (-6.07 eV), indicating stronger thermodynamic stability of
3 2
the Dim-C4-CN-induced 1D perovskite structure.

Based on the above results, we present a unified model correlating ligand molecular structure with
perovskite dimensional selectivity (Fig. 1e). The cationic imidazolium moieties first occupy the
A-sites to balance the charge of [PbI ]− motif in low-dimensional perovskites. When the terminal
3
groups are excessively long, the resulting steric hindrance prevents the growth of [PbI ]− unit,
3
yielding a 0D perovskite structure. With shortened terminal length, the ligand aligns with [PbI ]−
3
moiety, producing a parallel-aligned 1D perovskite architecture. Extending the inter-imidazolium
distance induces ligand re-orientation to occupy the A sites of another [PbI ]− unit, forming a
3
bridged 1D perovskite architecture.

Morphological and spectroscopic analysis of perovskite films
Systematic scanning electron microscopy (SEM) analysis revealed that Dim-C4-CN-modified
perovskite films exhibited markedly improved morphological homogeneity and enhanced grain
growth (Supplementary Figs. 21-22). Upon increasing the concentration of the three ligands, well-
defined low-dimensional perovskite phases were preferentially accumulating at 3D perovskite
grain boundaries (Supplementary Figs. 23-24). Atomic force microscopy (AFM) further
corroborated these observations, revealing a substantial improvement in film quality following
Dim-C4-CN modification, as quantified by a reduction in surface roughness from 47.4 nm
(unmodified reference film) to 21.2 nm (Dim-C4-CN-modified film) (Fig. 2a). Kelvin probe force
microscopy (KPFM) measurements provided quantitative assessment of surface potential
distribution across the perovskite films (Fig. 2b). Compared to the reference sample, the modified
perovskite films consistently displayed reduced surface potential fluctuations, indicative of
improved charge transport and lower surface defect densities29. Notably, Dim-C4-CN-modified
films exhibited the most uniform potential distribution, highlighting exceptional interfacial
homogeneity (Fig. 2c). The surface potential variation was dramatically reduced from 143.2 mV
in the reference to 10.8 mV with Dim-C4- CN modification, reflecting a substantially optimized
potential landscape conductive to charge extraction in the p-i-n device architectures30. Ultraviolet
photoelectron spectroscopy (UPS) measurements corroborated these findings, showing a reduction
in work function from 4.51 eV (control film) to 4.36 eV (Dim-C4-CN-modified film)
(Supplementary Fig. 25), consistent with KPFM results, suggests enhanced n-type character in the
modified films, potentially improving carrier extraction efficiency in photovoltaic devices.

Multimodal spectroscopic characterization and systematic computational analysis reveals robust
multidentate coordination between functional ligands (imidazolium/cyano moieties) and PbI
2
frameworks, with binding strength quantitatively assessed through multiple complementary
techniques: vibrational frequency shifts (Fourier transform infrared spectroscopy, FTIR)
(Supplementary Figs. 26-28), chemical perturbations (nuclear magnetic resonance, NMR)
(Supplementary Figs. 29-30) and optical property variations (Supplementary Fig. 31). These
coordinated interactions critically control both low-dimensional phase crystallization and targeted
defect passivation in resulting perovskite films. X-ray photoelectron spectroscopy (XPS) analysis
of modified perovskite films demonstrated consistent downward shifts in Pb 4f core-level binding
energies, with the Dim-C4-CN-modified sample showing the most substantial energy shift (0.17
eV) -clear evidence of enhanced electronic coupling between Dim-C4-CN ligand and [PbI ]⁻
3
octahedra units31 (Supplementary Fig. 32).

To fundamentally understand the chemical passivation mechanism enabled by this low-
dimensional modification approach, we conducted comprehensive photoluminescence (PL)
studies including spatial mapping (Fig. 2d) (Supplementary Fig. 33). Compared to the reference,
all three ligand-modified perovskite films exhibit enhanced PL intensity, with the Dim-C4-CN-
modified perovskite film showing the strongest PL signal. Time-resolved photoluminescence
(TRPL) further reveal that the Dim-C4-CN-modified perovskite films exhibit prolonged charge-
carrier lifetimes, which we attribute to the effective suppression of non-radiative recombination
via trap-state passivation32–34. The reduction in defect state density achieved through low-
dimensional perovskite formation was further confirmed by space-charge-limited current
measurements35,36 (Supplementary Figs. 34-35), providing additional quantitative confirmation of
the improved electronic quality in modified films. To probe the specific impact of low-dimensional
perovskite on the strain state within the three-dimensional perovskite matrix, grazing-incidence X-
ray diffraction (GIXRD) measurements coupled with the sin2ψ method were performed on both
the reference and Dim-C4-CN-modified perovskite films. Specifically, the film stress (σ) was
determined by fitting the variation of 2θ as a function of sin2ψ, from which the extent of residual
strain was inferred based on the slope of the linear regression. Remarkably, the Dim-C4-CN-
modified perovskite film exhibited a substantially reduced negative slope relative to the control
film, as evidenced by the linear fitting of sin2ψ (Supplementary Fig. 36).

Crystallisation dynamics of perovskite films
The Grazing-incidence wide angle x-ray scattering (GIWAXS) patterns of all three ligands-
modified perovskite films display distinct low-dimensional phase signatures at lower q-values,
differing markedly from conventional 3D perovskites (q = 1.0 Å⁻1)37. The characteristic peaks for
low-dimensional phases appear at q = 0.55 Å⁻1 (Dim-C2-CH ), 0.57 Å⁻1 (Dim-C2-CN), and 0.58
3
Å⁻1 (Dim-C4-CN), corresponding to the formation of 0D (Dim-C2-CH ) Pb I Br , 1D Dim-C2-
3 3 3 4.9 7.1
CN(PbI ) and 1D Dim-C4-CN(PbI ) perovskite phases, respectively (Fig. 3a-d).
3 2 3 2
XRD analysis of Dim-C4-CN confirmed the presence of the 1D perovskite phase Dim-C4-
CN(PbI ) , with peak positions and relative intensities matching precisely with single-crystal
3 2
reference data (Supplementary Fig. 37). All three low-dimensional/3D perovskite films exhibit
significantly enhanced 3D perovskite peak intensities, compared to the reference film,
demonstrating that the low-dimensional modification strategy substantially improves bulk
crystallinity (Fig. 3e). Notably, the Dim-C4-CN-modified perovskite demonstrates superior
crystallinity among the samples, corroborating the morphological observations. GIWAXS analysis
further indicates that the 1D perovskite phase derived from Dim-C4-CN exhibits a markedly
enhanced out-of-plane orientation within the 3D perovskite matrix compared to its Dim-C2-CN
counterpart (Fig. 3f). Such preferential orientation is anticipated to facilitate more efficient vertical
charge transport, thereby contributing to the overall improvement in device performance.

To probe the influence of low-dimensional perovskite on the crystallization kinetics,
in-situ
absorption spectroscopy was utilized. The results demonstrated that ligands Dim-C4-CN
substantially prolonged the crystallization process during thermal annealing, promoting enlarged
grain growth through retarded crystallisation38 (Fig. 3g-i). To gain deeper mechanistic insight into
ligand-mediated crystallization control, we conducted in-situ GIWAXS measurements to track the
crystallization pathways in both reference and Dim-C4-CN-modified perovskite films (Fig. 3j-k).
Quantitative analysis of the temporal evolution of 3D perovskite peak intensities revealed
significantly slower crystallization kinetics in Dim-C4-CN-modified samples compared to the
reference. This provides direct experimental verification that Dim-C4-CN effectively modulates
crystallization dynamics through controlled phase evolution (Fig. 3l). Notably, the GIWAXS
patterns of Dim-C4-CAN-modified samples exhibited new characteristic peaks at q = 0.57 Å⁻1,
corresponding to 1D perovskite phases. Furthermore, in-situ GIWAXS analysis was also
conducted on Dim-C2-CH -modified perovskite thin films (Supplementary Fig. 38). Unlike the
3
rapid crystallization observed in 1D perovskites, the formation of 0D perovskite structures
necessitates extended annealing durations, which can be ascribed to pronounced interaction
between the Dim-C4-CN ligand and the perovskite constituents, coupled with their inherently
lower formation energy. These transient 1D perovskite phase perform two critical functions: (i)
they kinetically compete with and retard the direct reaction between PbI and organic salts and (ii)
2
they serve as structural templates to guide the oriented growth of 3D perovskite domains. This
dual functionality establishes a more a more effective pathway for crystallization control, enabling
the formation of high-quality perovskite films with improved morphological and electronic
properties39.

Photovoltaic performance studies
Benefiting from the optimized crystallization process and enhanced film quality enabled by low-
dimensional perovskite modification, we further evaluated the photovoltaic performance of the
resulting devices employing this strategy (Fig. 4a). The devices were fabricated with a
conventional inverted structure, exhibiting a bandgap of 1.54 eV. The reference device achieved a
PCE of 24.13%, while the Dim-C2-CH and Dim-C2-CN-modified devices demonstrated
3
improved PCEs of 25.46% and 25.17%, respectively. Notably, the champion device based on Dim-
C4-CN modification achieved a superior PCE of 27.21% with a V of 1.197 V, a J of 26.37
OC SC
mA cm⁻2 and a FF of 86.21% (Supplementary Fig. 39-40 and Supplementary Tables 32-33),
demonstrating the most significant performance enhancement among all modified devices. The
cross-sectional SEM images of the device are also provided in Supplementary Fig. 41. Excellent
consistency is observed between the J
SC
values determined via current density–voltage (J–V)
measurements and those calculated from the integrated external quantum efficiency (EQE) spectra
(Supplementary Fig. 42). Importantly, the champion device achieved a stabilized PCE of 27.06%
(Supplementary Fig. 43). Independent certification through Chinese National Center of Inspection
on Solar Photovoltaic Products Quality confirmed the PCE of 27.02% for our champion device
(Supplementary Fig. 44). Notably, this result outperforms previously reported values for 1D-
modified approaches (Fig. 4b and Supplementary Table 34)40–42. Furthermore, statistical
evaluation of 37 separately fabricated devices further attests to the excellent reproducibility
(Supplementary Fig. 45). A comparative analysis of the PCEs between 1D and 2D modified
approaches further demonstrate the superiority of this work43–46 (Supplementary Fig. 46 and
Supplementary Table 35). These results collectively demonstrate that the well-designed ligand-
induced formation of highly out-of-plane oriented 1D perovskites leads to significant
improvements in device performance. The performance enhancement can be attributed to
optimized charge transport dynamics and effective suppression of non-radiative recombination, as
corroborated by electrochemical impedance spectroscopy and conventional Mott-Schottky
measurements (Supplementary Figs. 47-48). To further substantiate the analysis of the
concomitant enhancement in device performance, we conducted additional photoluminescence
quantum yield (PLQY) measurements and quantitatively evaluated the corresponding quasi-Fermi
level splitting (QFLS). The PLQY of both the control and ligand-modified perovskite films were
acquired, from which the respective QFLS values were derived (Supplementary Fig. 49). The
control perovskite film exhibits a PLQY of 7.510%, translating to a QFLS of 1.185 eV. In contrast,
the Dim-C4-CN-modified film attains a markedly improved PLQY of 12.82%, corresponding to
an elevated QFLS of 1.200 eV. The spatially confined photogenerated carriers in 0D perovskites
system47 and the poor orientation of parallel-aligned 1D perovskites system, fundamentally limit
further enhancement of charge transport properties. The bridged 1D perovskite with high
orientation alignment within the 3D perovskite film significantly enhances charge transport,
thereby achieving optimal photovoltaic performance. Based on the aforementioned 1D
modification strategy, devices with an effective area of 1 cm² were fabricated, achieving an optimal
PCE of 25.95% (Supplementary Fig. 50). The implementation of this dimensional strategy enabled
the successful scaling of perovskite photovoltaics to 30×30 cm2 perovskite solar modules, resulting
in a champion PCE of 21.41% (Fig. 4c). Notably, our approach was also successfully extended to
wide-bandgap perovskite, including 1.67 eV (Supplementary Figs. 51-52 and Supplementary
Table 36) and 1.84 eV (Supplementary Figs. 53-54 and Supplementary Table 37) bandgap
perovskite solar cells, where the Dim-C4-CN-modified devices achieved a champion PCE of 23.45%
and 19.00%, respectively, representing the universality and potential application value of the Dim-
C4-CN.

Comprehensive stability assessment revealed exceptional environmental and operational
robustness in the Dim-C2-CH , Dim-C2-CN and Dim-C4-CN-modified devices. Among which,
3
unencapsulated Dim-CA4-CN-modified devices retained 90.8% of their initial PCE after 5,000
hours of storage at 40 ± 5% relative humidity (RH) and room temperature (ISOS-D-1),
significantly outperforming the reference devices (43.9% retention under the same conditions) (Fig.
4d). The enhancement in humidity stability is attributed to the improved hydrophobicity
(Supplementary Fig. 55) and the superior film quality. Furthermore, long-term operational stability
was assessed under continuous illumination (2,000 hours, 60 °C, N atmosphere, ISOS-L-2I), with
2
the devices maintaining 94.3% of their initial PCE (Fig. 4e). Long-term stability monitoring at 85%
RH and 85 °C (ISOS-D-3) revealed that the Dim-C4-CN-modified devices retained 87% of their
initial PCE after 800 hours of continuous operation (Supplementary Fig. 56).

Methods
Materials
Indium tin oxide (ITO) glass (TX11-12AR) was provided by Suzhou ShangYang Solar
Technology Co., Ltd. NiOx (purity≥99.99%), Formamidinium Iodide (FAI, purity≥ 99.5%), PbI
2
(99.999%) and cesium iodide (CsI, 99.999%) were was provided by Advanced Election
Technology Co., Ltd., [4-(3,6-Dimethyl-9H-carbazol-9-yl)butyl]phosphonic Acid (Me-4PACz,
purity≥99%) and Lead(II) bromide (PbBr , purity≥98%)was acquired by TCI. Imidazole
2
(purity≥99.5%), sodium hydride (anhydrous), 4-chlorobutyronitrile (purity≥97%), 1-
chlorobutane(purity≥99.5%), 1,2-dibromoethane (purity≥97%), 1,4-dibromobutane (purity≥97%),
3-bromopropyl methyl ether (purity≥98%) and Octadecanammonium iodide (ODAI ,
2
purity≥99.5%) were bought from Shanghai Aladdin Biochemical Technology Co., Ltd. [6,6]-
phenyl-C61-butyric acid methyl ester (PCBM, purity >99%) were purchased from Nano-C. 2,9-
Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, purity=99%), Methanaminium iodide (MAI,
purity≥99.9%), 1,3-Diaminopropane dihydroiodide (PDAI , purity=99.5%), 2-
2
Phenethylammonium chloride (PEACl, purity=99.5%), Phenethylammonium bromide (PEABr,
purity=99.5%) and methylammonium chloride (MACl, purity=99.9%) were purchased from
Xi’an Yuri Solar Co., Ltd. Tetrahydrofuran (THF, anhydrous, ≥99.9%), DMSO (anhydrous,
99.9%), Dimethylformamide (DMF, anhydrous, 99.8%), chlorobenzene (CB, anhydrous, 99.9%)
and isopropanol (IPA, purity≥99.5%), dichloromethane (DCM, purity=99.5%) and Ethyl alcohol
(anhydrous, 99.5%) were purchased from Sigma-Aldrich.

Synthesis of intermediates and ligands
Compounds N-(3-cyanopropyl)imidazole and N-b utylimidazole were obtained as the synthetic
intermediate, and compounds 1,1'-(ethane-1,2-diyl)bis(3-(3-cyanopropyl)-1H-imidazol-3-ium) di
(bromide); 1,1'-(butane-1,4-diyl)bis(3-(3-cyanopropyl)-1H-imidazol-3-ium) di (bromide); 1,1'-
(ethane-1,2-diyl)bis(3-butyl-1H-imidazol-3-ium) di (bromide) and 3,3'-(Ethane-1,2-diyl)bis(1-(3-
methoxypropyl)-1H-imidazol-3-ium bromide were obtained as the final ligand. All reagents from
commercial sources were used without further purification. Solvents were dried and purified using
standard techniques. All compounds were characterized by 1H NMR on a Bruker Avance III
Ultrashielded Plus instrument.

Synthesis of intermediate N-(3-cyanopropyl)imidazole. Under N protection, 20.28 g (0.3
2
mol) of imidazole was dissolved in 300 mL of THF in a 500 mL three-neck flask and cooled to
0 ℃, then 14.3 g (0.3 mol) of 50% sodium hydride was added slowly, followed by stirring at 0 ℃
for 1.5 hours. After that, 30.85 g (0.3 mol) of 4-chlorobutyronitrile was added, and the temperature
was raised to 60 ℃ for 2 hours. The reaction progress was monitored by thin layer chromatography
(TLC) until the starting materials disappeared. The reaction was quenched with water, and the
aqueous phase was extracted with dichloromethane (DCM). The combined organic phases were
dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The oil
was used directly for the next step without further purification.

Synthesis of intermediate N-butylimidazole. Under N protection, 5 g (73.4 mmol) of
2
imidazole was dissolved in 50 mL of THF in a 100 mL three-neck flask. The temperature was
cooled to 0 ℃, and 3.53 g (73.4 mol) of 50% sodium hydride was added, followed by stirring at
0 ℃ for 1.5 hours. Then, 10.06 g (73.4 mmol) of 1-chlorobutane was added, and the temperature
was raised to 60 ℃ and stirred for 2 hours. The reaction progress was monitored by TLC until the
starting materials disappeared. The reaction was quenched with water, and the aqueous phase was
extracted with DCM. The combined organic phases were dried over anhydrous sodium sulfate,
filtered, and concentrated under reduced pressure and produced 6.3 g of a colorless oil, with a yield
of 69.1%. The oil was used directly for the next step without further purification.

Synthesis of ligand 1,1'-(ethane-1,2-diyl)bis(3-(3-cyanopropyl)-1H-imidazol-3-ium) di
(bromide). The compound 1,1'-(ethane-1,2-diyl)bis(3-(3-cyanopropyl)-1H-imidazol-3-ium) di
(bromide) is denoted as Dim-C2-CN. Under N protection, 5 g (37 mmol) of N-(3-
2
cyanopropyl)imidazole was dissolved in 100 ml three-neck flask with 1,2-dibromoethane (3.47 g,
18.5 mmol) and 50 mL of ethanol. The mixture was heated to reflux for 48 hours. After that, the
reaction mixture was filtered, and the solid was dried under vacuum at 65 ℃, producing 3.4 g
white solid (48.6% yield). 1H NMR (400 MHz, D O) δ 8.91 (s, 1H), 7.61 (s, 1H), 7.48 (s, 1H),
2
4.72(d, J = 17.68 Hz, 2H), 4.31 (t, J = 6.92 Hz, 2H), 2.54 (t, J = 6.88 Hz, 2H), 2.21 (t, J = 6.88 Hz,
2H). High-resolution mass spectrometry (HRMS, APPI+, Orbitrap, m/z) calcd for [M-2Br]2+
[C H N ]2+: 149.0948; found 149.0941.
16 22 6

Synthesis of 1,1'-(butane-1,4-diyl)bis(3-(3-cyanopropyl)-1H-imidazol-3-ium) di (bromide).
The compound 1,1'-(butane-1,4-diyl)bis(3-(3-cyanopropyl)-1H-imidazol-3-ium) di(bromide) is
denoted as Dim-C4-CN. Under N protection, 5 g (37 mmol) of N-(3-cyanopropyl)imidazole was
2
dissolved in 100 mL three-neck flask with 1,4-dibromobutane (3.99 g, 18.5 mmol) and 50 mL of
ethanol. The mixture was heated to reflux for 48 hours. After that, the reaction mixture was filtered,
and the solid was dried under vacuum at 65 ℃, producing 3.9 g white solid (51.9% yield). 1H
NMR (400 MHz, D O) δ 8.86 (s, 1H), 7.52 (s,1H), 7.49(s, 1H), 4.32(t, J = 6.8 Hz, 3H), 4.21 (s,
2
2H), 2.56 (t, J = 6.8 Hz, 2H), 2.21 (t, J = 6.88 Hz, 2H), 1.87 (s, 2H). HRMS (APPI+, Orbitrap, m/z)
calcd for [M-2Br]2+ [C H N ]2+: 163.1104; found 163.1112.
18 26 6

Synthesis of 1,1'-(ethane-1,2-diyl)bis(3-butyl-1H-imidazol-3-ium) di (bromide). The
compound 1,1'-(ethane-1,2-diyl)bis(3-butyl-1H-imidazol-3-ium) di (bromide) is denoted as Dim-
C2-CH . Under N protection, 5 g (40.3 mmol) of N-butylimidazole was dissolved in 100 ml three-
3 2
neck flask with 1,2-dibromoethane (3.79 g, 20.15 mmol) and 50 mL of ethanol. The mixture was
heated to reflux for 48 hours. After that, the reaction mixture was filtered, and the solid was dried
under vacuum at 65 ℃, producing 3.2 g white solid (44.4% yield). 1H NMR (400 MHz, D O) δ
2
8.77 (s, 1H), 7.54 (s, 1H), 7.44(s, 1H), 4.71(d, J = 8.6 Hz, 2H), 4.14 (t, J = 7.04 Hz, 2H), 1.73-1.77
(m, 2H), 1.21-1.15 (m, 2H), 0.86-0.82 (m, 3H). HRMS (APPI+, Orbitrap, m/z) calcd for [M-2Br]2+
[C H N ]2+: 138.1152; found 138.1157.
16 28 4

Synthesis of 3,3'-(Ethane-1,2-diyl)bis(1-(3-methoxypropyl)-1H-imidazol-3-ium bromide.
The compound 3,3'-(Ethane-1,2-diyl)bis(1-(3-methoxypropyl)-1H-imidazol-3-ium bromide is
denoted as Dim-C2-OMe. Under N₂ protection, imidazole (5 g, 73.4 mmol) and THF (50 mL) were
added to a 100 mL three-necked flask. The mixture was cooled to 0°C, followed by the addition
of 50% sodium hydride (3.53 g, 73.4 mmol). After stirring at 0 °C for 1.5 hours, 3-bromopropyl
methyl ether (11.23 g, 73.4 mmol) was added. The reaction was warmed to 60 °C and stirred for
2 hours. TLC monitoring confirmed the complete consumption of the starting material. The
reaction was quenched with water, and the aqueous phase was extracted with DCM. The combined
organic phases were dried over anhydrous sodium sulfate, filtered, and concentrated under reduced
pressure to provide a colorless oil. The oil was used for next step directly without further
purification. Under N protection, the oil (5 g, 35.7 mmol) and 1,2-dibromoethane (3.35 g, 17.85
2
mmol) were added to a 100 mL three-necked flask with 50 mL ethanol. The mixture was heated
to reflux for 48 hours, during which a solid precipitated. The solid was collected by filtration and
vacuum-dried at 65 °C to yield 3.5 g of an off-white solid (41.9% yield). ¹H NMR (400 MHz,
DMSO-d ) δ 9.25 (s, 2H), 7.84 (s, 2H), 7.72 (s, 2H), 4.75 (s, 4H), 4.24–4.20 (t, J = 8 Hz, 4H),
6
3.32–3.31 (d, J = 4 Hz, 4H), 3.23 (s, 6H), 2.51–2.50 (t, J = 4 Hz, 4H), 2.06–1.99 (p, J = 8 Hz, 4H).
HRMS (APPI+, Orbitrap, m/z) calcd for [M-2Br]2+ [C H N O ]2+: 154.1101; found 154.1098.
16 28 4 2

Synthesis of single crystals
(Dim-C2-CH ) Pb I Br : a single crystal of the target compound was synthesized by dissolving
3 3 3 4.9 7.1
0.1 mmol Dim-C2-CH and 0.2 mmol PbI in 1 mL DMSO solvent, followed by heating at 80 °C
3 2
for 1 h under continuous stirring. The crystallization was then achieved through a slow antisolvent
diffusion method, where THF was employed as the antisolvent. After three days of controlled
diffusion at room temperature, well-defined crystals were obtained. Dim-C2-OMe(PbI ) : a single
3 2
crystal of the target compound was synthesized by dissolving 0.1 mmol Dim-C2-OMe and 0.2
mmol PbI in 1 mL DMSO solvent, followed by heating at 80 °C for 1 h under continuous stirring.
2
The crystallization was then achieved through a slow antisolvent diffusion method, where THF
was employed as the antisolvent. After three days of controlled diffusion at room temperature,
well-defined crystals were obtained. Dim-C2-CN(PbI ) : a single crystal of the target compound
3 2
was synthesized by dissolving 0.1 mmol Dim-C2-CN and 0.2 mmol PbI in 1 mL DMSO solvent,
2
followed by heating at 80 °C for 1 h under continuous stirring. The crystallization was then
achieved through a slow antisolvent diffusion method, where THF was employed as the antisolvent.
After one week of controlled diffusion at room temperature, well-defined crystals were obtained.
Dim-C4-CN(PbI ) : a single crystal of the target compound was synthesized by dissolving 0.1
3 2
mmol Dim-C4-CN and 0.2 mmol PbI in 1 mL DMSO solvent, followed by heating at 100 °C for
2
1 h under continuous stirring. The crystallization was then achieved through a slow antisolvent
diffusion method, where THF was employed as the antisolvent. After three days of controlled
diffusion at room temperature, well-defined crystals were obtained.

Perovskite precursor preparation
1.54 eV bandgap perovskite precursor: the 1.67M Cs MA FA PbI perovskite precursor
0.05 0.05 0.9 3
contains 21.7 mg CsI, 13.3 mg MAI, 224.2 mg FAI and 731.8 mg PbI in 1ML DMF/DMSO (4:1
2
in volume) solution. An additional 38 mg of PbI₂ and 13.6 mg of methylammonium chloride
(MACl) were introduced into the above system. For the Dim-C2-CH , Dim-C2-CN and Dim-C4-
3
CN modified perovskite precursor, 0.2 mg Dim-C2-CH /Dim-C2-CN/Dim-C4-CN was weighed
3
using a one-millionth balance and finally added it to the precursor solution system. After stirring
the solution for 2 hours to ensure complete dissolution, it was left to stand for 1 hour and
subsequently filtered for use. 1.67 eV bandgap perovskite precursor: the 1.4M
Cs FA MA Pb(I Br ) perovskite precursor contains 18.2 mg of CsI, 192.6 mg of FAI,
0.05 0.8 0.15 0.76 0.24 3
536 mg of PbI , 131 mg of PbBr , 23.5 mg of MABr in 1 mL DMF: DMSO (4:1 in volume). To
2 2
enhance the crystallinity of the wide-bandgap perovskite film, 0.2 mg ODAI was then weighted
2
via a one-millionth balance to added as an additive in the above 1.67 eV bandgap perovskite
precursor system. For the Dim-C4-CN modified perovskite precursor, 0.15 mg Dim-C4-CN was
weighed using a one-millionth balance and finally added it to the precursor solution system. After
stirring the solution for 1 hours to ensure complete dissolution, it was left to stand for 1 hour and
subsequently filtered for use. 1.84 eV bandgap perovskite precursor: 1.84 eV perovskite was
consisted of 115 mg PbI , 65 mg CsI, 129 mg FAI, 275 mg PbBr , all precursors were dissolved
2 2
in 1 mL mixture solvent of DMF and DMSO (volume ratio = 4:1). For the Dim-C4-CN modified
perovskite precursor, 0.15 mg Dim-C4-CN was weighed using a one-millionth balance and finally
added it to the precursor solution system. After stirring the solution for 1 hours to ensure complete
dissolution, it was left to stand for 1 hour and subsequently filtered for use.

Perovskite solar cells fabrication
For 1.54 eV bandgap perovskite solar cells: the ITO glass was ultrasonically cleaned twice in
sequence using deionized water, anhydrous ethanol , and IPA, with each ultrasonic cleaning lasting
10 min. Cleaned ITO-coated glass substrates were subjected to ultraviolet-ozone treatment (30
min) for surface activation. A NiO hole layer was deposited via spin-coating (4,000 rpm, 30 s)
x
from a colloidal dispersion (Disperse in a mixed solvent of IPA and deionized water with a volume
ratio of 1:3 at a concentration of 5 mg/mL), followed by thermal annealing (150 °C, 10 min,
ambient atmosphere). The substrates were transferred to a nitrogen-filled glovebox for subsequent
processing. A self-assembled monolayer (SAM) of Me-4PACz was formed by spin-coating (4,000
rpm, 30 s) from a 60 μL SAM/IPA solution (0.5 mg/mL), with post-annealing (100 °C, 10 min).
This was followed by dynamic spin-coating (4,500 rpm, 25 s) of PEACl in IPA (1 mg/mL) and
thermal treatment (100 °C, 5 min). 1.54 eV perovskite precursor solution with/without Dim-C2-
CH /Dim-C2-CN/Dim-C4-CN was spin-coated on the as-prepared SAM/ITO substrates at 5,000
3
r.p.m. for 40 s, during which 200 μL CB was dripped onto the center of film at 10 s before the end
of spin-coating. The samples were annealed at 100°C for 30 min and then allowed to cool to room
temperature naturally. The mixed solution of PDAI and PEACl is composed of 1 mg/mL PDAI
2 2
(1 mg dissolved in 1 mL IPA) and 1 mg/mL PEACl (1 mg dissolved in 1 mL IPA). After thorough
stirring, 80 µL of the supernatant was taken for the spin-coating process (4,500 rpm, 25 s) and
annealed (100 °C, 5 min). PCBM (20 mg/mL) and BCP (1 mg/mL) in IPA was sequentially spin-
coated. Finally, a 100 nm silver top electrode was thermally evaporated through a shadow mask
under high vacuum. For 1.67 eV bandgap perovskite solar cells: the cleaning of ITO and the
preparation of the nickel oxide layer and SAM layer follow the same fabrication process as
described above. Then, PEABr in IPA solution (1 mg/mL) was dynamically spin-coated on top of
SAM layer (4,000 rpm, 30 s) and annealed at 100 °C for 5 min. 1.67 eV perovskite precursor
solution with/without Dim-C4-CN was spin-coated on the as-prepared SAM/ITO substrates at
5,000 r.p.m. for 40 s, during which 200 μL CB was dripped onto the center of film at 10 s before
the end of spin-coating. The samples were annealed at 100 °C for 15 min and then allowed to cool
to room temperature naturally. The PEABr (1 mg/mL in IPA solution) interlayer was subsequently
applied (4,500 rpm, 25 s) and annealed (100 °C, 5 min). PCBM, BCP and Ag layers were
subsequently fabricated following the identical procedure as described above. For 1.84 eV
bandgap perovskite solar cells: the cleaning of ITO and the preparation of the nickel oxide layer
and SAM layer follow the same fabrication process as described above. Then, PEABr in IPA
solution (1 mg/mL) was dynamically spin-coated on top of SAM layer (4,000 rpm, 30 s) and
annealed at 100 °C for 5 min. 1.84 eV perovskite precursor solution with/without Dim-C4-CN was
spin-coated on the as-prepared SAM/ITO substrates at 5,000 r.p.m. for 40 s, during which 200 μL
CB was dripped onto the center of film at 1 0 s before the end of spin-coating. The samples were
annealed at 100°C for 15 min and then allowed to cool to room temperature naturally. The PEABr
(1 mg/mL in IPA solution) interlayer was subsequently applied (4,500 rpm, 25 s) and annealed
(100 °C, 5 min). PCBM, BCP and Ag layers were subsequently fabricated following the identical
procedure as described above.

Perovskite solar modules fabrication
Perovskite thin films were deposited via slot-die coating under ambient atmospheric conditions, at
a RH of 30–40%. An air knife system, positioned approximately 10 cm above the substrate holder
and operated at an internal pressure of 20 PSI, was employed during the process. The perovskite
precursor solution was supplied to the slot-die head through a tubing system connected to a syringe
pump, allowing accurate regulation of the dispensing rate. Coating was conducted at room
temperature with optimized parameters, including a substrate translation speed of 15 cm min⁻1,
a
solution injection rate of 100 µL min⁻1, and a head-to-substrate spacing maintained between 0.2
and 0.3 mm. Following deposition, the wet films were immediately subjected to vacuum pumping,
achieving a pressure of 10 Pa within 20 seconds. Subsequently, the samples were rapidly
transferred to a hot plate preheated to 150 °C and annealed for 15 min. Thereafter, sequential
deposition of a 20 nm C layer and a 5 nm SnO layer was carried out. Finally, the devices were
60 2
completed with a 5 nm ITO layer and a 100 nm Cu capping layer. Electrical connectivity in the
perovskite solar modules was defined by a three-step laser patterning process (P1-P3). This
involved: (P1) isolating the bottom electrodes at 2.96 W and 25 μm; (P2) creating series
connections between adjacent sub-cells at 1.33 W and 50 μm for low contact resistance; and (P3)
isolating the top electrodes at 0.96 W and 20 μm without damaging the underlying functional layers.

Characterizations
GIWAXS measurements were performed at the Synchrotron & Printable Electronic Lab,
Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic University with SAXSFocus
3.0 (GKINST Co., LTD.) equipped with a Cu X-ray Source (8.05 9 keV, 1.54 Å) and an EIGER
2R 500K detector. The grazing incidence angle was set to 0.8 degrees. XRD patterns were obtained
by Rigaku Smart Lab (λ= 1.54 Å). The single crystal XRD data of (Dim-C2-CH ) Pb I Br ,
3 3 3 4.9 7.1
Dim-C2-OMe(PbI ) , Dim-C2-CN(PbI ) and Dim-C4-CN(PbI ) were collected at 299 K using
3 2 3 2 3 2
Cu radiation (λ = 1.54178 Å) on a Bruker SMART APEX II CCD detector. The relevant
crystallographic results can be found in Table S2. TRPL measurements were performed using an
FLS 1,000 fluorescence spectrometer (Edinburgh Instruments, UK) equipped with a 445 nm laser.
Steady-state PL mapping measurements were performed u a Meite Optoelectronics system at a
scan rate of 1 Hz to ensure high image quality. The excitation source was a continuous-wave diode
laser with a wavelength of 445 nm, focused onto the sample surface through a 100× objective lens.
The PL emission was collected by the same objective and directed to a spectrometer equipped with
a charge-coupled device detector. The mapping area was 50 × 50 μm2. All measurements were
conducted under ambient conditions at room temperature. AFM and KPFM images were collected
at a Bruker AFM. Topographic images of the films were captured using a Bruker AFM equipped
with a Dimension Edge and ScanAsyst in tapping mode. An etched silicon cantilever was utilized
at an approximate load of 2 nN, with a scan rate of 1 Hz for images measuring 5 μm × 5 μm. The
KPFM tests were conducted by Electrical and Magnetic Lift Modes (PeakForce KPFM) with
SCM-PIT-V2 tips. The scanning rate was 0.5 Hz and Driver Amplitude is 500 mV. The J-V
characteristics of the PSC devices were evaluated with an IVS-KA Enlitech solar simulator
equipped with an AM 1.5 filter at 100 mW/cm2, utilizing a Keithley SMU source. Prior to
measurement, light intensity was calibrated using a standard reference cell. For single-junction
PSCs, the area of tests mark was 0.049 cm2. An Enli Technology Co., Ltd. QE-R system was
employed to obtain the corresponding EQE spectrum in ambient air. In situ absorption testing is
performed using a spectrometer equipped with a heating stage to collect absorption spectra,
allowing for the monitoring of spectral changes during the annealing process. 1H NMR and 13C
NMR spectra were recorded on a Bruker Avance III HD 400 MHz NMR spectrometer (Bruker,
Germany). HRMS data was recorded using a Thermo Scientific - LTQ Velos Orbitrap MS in
positive atmospheric pressure photoionization (+APPI) mode. FTIR spectra were collected on a
Thermo Scientific Nicolet iS50 spectrometer (Thermo Fisher Scientific, USA) using KBr pellet
method (sample:KBr = 1:100 ratio). The spectral range was 400-4,000 cm⁻1 with 4 cm⁻1 resolution
and 32 scans, using pure KBr as background reference. XPS measurements were performed on a
Thermo Scientific ESCALAB Xi+ system (Thermo Fisher Scientific, USA) equipped with an Al
Kα X-ray source operated at 15 kV and 10 mA. All binding energies were referenced to the C 1s
peak at 284.8 eV for charge correction. The analysis chamber was maintained at ultra-high vacuum
(<5×10⁻9 mbar). High-resolution scans were acquired with 20 eV pass energy and 0.05 eV step
size. UPS was conducted on the same ESCALAB Xi+ system using He I excitation source at 10
kV and 5 mA. A sample bias of -5 V was applied to observe the secondary electron cutoff. The
measurements were performed under ultra-high vacuum (<2×10⁻9 mbar). PLQY measurements
were performed using a LuQY Pro (LP20-32) system (Quantum Yield Berlin GmbH) under
illumination equivalent to one sun. The samples were excited within an integrating sphere using a
532 nm laser with a spot area of 0.01 cm2, calibrated to an intensity corresponding to standard 1
sun conditions. The resulting PLQY values were subsequently employed to determine the QFLS.

DFT calculations
The geometries of bis-imidazolium ligands in DMSO solvent were optimized with the PBE0/cc-
pVTZ calculations using ORCA 5.0.4 program48. The crystal structure optimization of (Dim-C2-
CH ) Pb I , Dim-C2-OMe(PbI ) , Dim-C2-CN(PbI ) , Dim-C4-CN(PbI ) and the analogs with
3 3 3 12 3 2 3 2 3 2
various terminal groups used VASP code49 with a plane wave basis set and projected augmented
wave pseudopotentials and Grimme’s D3 corrections50. The 0D, parallel 1D and bridged 1D
perovskite models employed a 2x2x2, 3x3x2, 3x1x3 k-point mesh, respectively. The convergence
thresholds were set to 10–6 eV for energy and 0.05 eV Å−1 for the norm of the atomic forces. The
1D PbI clusters with bis-imidazolium ligands were optimized with GFN2-xTB method51, where
2
we first relaxed the ligand structures according to a fixed structure of PbI cluster and then relaxed
2
both ligands and PbI cluster.
2

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "The authors develop a series of bis-imidazolium ligands to precisely control the formation of low-dimensional perovskites, establishing clear structure-property relationships between ligand design and resulting perovskite dimensionality. Distinct from conventional studies, this work begins with the design of organic ligands, establishing an in-depth relationship between the chemical structure of the ligands and the dimensionality and architecture of the induced single crystals. In addition, the study provided a detailed and comprehensive structural analysis of both the ligands and the single crystals, and achieved a high efficiency in the final device, demonstrating a certified efficiency of over 27% and exceptional stability. Overall, this study is of great importance and may attract broad interest in the related fields. The experimental results are solid and convincing. Therefore, I would recommend publication in Nature Communications after the authors adequately address the following comments:\n1. The device performance and analysis of chemical and structural properties with low-dimensional perovskites were well provided. But still, the reason for choosing the specific organic ligands is unclear. Why were bis-imidazolium ligands chosen, and what advantages do they offer compared to monofunctional imidazolium ligands? The author may need to strengthen the rationale explanation.\n2. The authors first optimized the intrinsic molecular structures of the four ligands. What is the primary purpose of highlighting this part of the study?\n3. Further detailed elucidation is necessary to explain the differences in performance enhancement of perovskite devices resulting from the distinct one-dimensional perovskite structures induced by Dim-C2-CN and Dim-C4-CN.\n4. In the device section, it is necessary to supplement the statistical photovoltaic parameters of devices incorporating different concentrations of Dim-C4-CN.\n5. On the defect properties, the authors provided PL mapping results, yet no related discussion was given. Further providing the PLQY results and QFLS analysis would strengthen the discussion on the defect properties and performance improvements of related devices. In addition, detailed information on the optical characterizations, e.g. TRPL and PL mapping, needs to be provided.\n6. There are some typos, including the reference formats and some figure labels, need to be checked and corrected.", "reviewer_2": "This study presents a molecular design strategy for bis-imidazolium ligands that enables precise dimensional control over perovskite architectures, ranging from 0D to parallel and bridged 1D configurations. By systematically varying terminal functional groups and inter-imidazolium spacing, author achieved controlled crystallization of high-quality 1D‑3D hybrid perovskite films with optimized crystallization kinetics and charge transport properties. Consequently, photovoltaic devices fabricated using these materials yield a certified PCE of 27.02%—representing a record performance for dimensionally engineered perovskite solar cells. This study provides universal design principles for perovskite dimensional modulation at the molecular level, holding significant theoretical and applied value for advancing the development of high-efficiency and stable perovskite optoelectronic devices. This study, both in its mechanistic investigations and experimental analyses — particularly regarding perovskite single crystals and ligand structural design — strikes me as an exceptionally sound and meaningful piece of research. Therefore, I recommend the acceptance of this study following the implementation of the minor revisions outlined below.\n1. Please elaborate on the reasons for selecting this specific series of ligands in the research design. The rationale for employing -CN as terminal modifications in the ligand design requires further explanation. Furthermore, apart from the -CN polar group, it is suggested that the author provide further clarification on whether other similar polar groups exhibit the same phenomenon.\n2. XRD patterns of the organic salts should be provided to compare with their perovskites or perovskite/perovskite heterostructures.\n3. Will the formation of 1d-3d hybrid perovskites affect the hydrophobicity of the film? It is recommended to provide contact Angle data.\n4. Does the formation of low-dimensional perovskite change the residual strain in 3D perovskite films? It is suggested that the author provide evidence to illustrate. Please reference: https://doi.org/10.1002/aenm.202101018.\n5. The author should further prove \"Upon increasing the concentration of the three ligands, well-defined low-dimensional perovskite phases were preferentially accumulating at 3D perovskite grain boundaries\" through experimental data.\n6. The positions of the Pb 4f7/2 and Pb 4f5/2 peaks in Fig. S30 are incorrect. It is recommended that the author correct them.\n7. It is suggested that the authors standardize the format of the nuclear magnetic resonance hydrogen spectra of the molecules in Figures S1-S8; it is recommended that the format of the relative energy values of molecules in Figures S9-S12 be unified.\n8. “mofidied” in the caption of Fig. 2 should be “modified”, and the spelling needs to be proofread.", "reviewer_3": "In this work, the authors successfully synthesized and characterized four distinct perovskite single-crystal structures by systematically modulating organic ligand chemistry. These crystals were effectively integrated into perovskite photovoltaic devices, achieving a certified power conversion efficiency (PCE) exceeding 27% along with excellent operational stability. The study demonstrates significant innovation, particularly in establishing explicit structure-property relationships between organic ligand design and low-dimensional crystal architectures. Supported by comprehensive characterization, I believe this work will significantly advance future research on low-dimensional/three-dimensional (2D/3D) heterojunction systems. Therefore, I would recommend this manuscript for publication in Nature Communications after the following revisions are addressed.\nComments to the authors：\n1.Regarding the single-crystal structures induced by the Dim-C2-CN and Dim-C4-CN ligands, does the current study focus exclusively on cyano (-CN) modified systems? It would be helpful to know if the investigation was extended to explore the specific crystal structures induced by ligands functionalized with other types of substituents, or if the -CN group was specifically chosen for a particular chemical reason.\n2.When substituting a methyl group with a cyano group on the ligand, it is necessary to elucidate the specific advantages conferred by this modification, either in terms of the ligand’s own properties or the resulting single-crystal packing. Please provide a clearer rationale for the selection of CN-functionalized ligands in this study.\n3.The origin of the simplified structural representation in Figure 1c should be clarified. Please specify whether it was obtained through computational simulation (e.g., DFT) or if it is a schematic abstraction of an experimentally determined single-crystal structure.\n4.For the stability tests conducted under 85°C and 85% relative humidity (ISOS-D-3), the authors should present the actual efficiency evolution data (absolute PCE values) in the supplement, rather than reporting only the normalized efficiency values.\n5.It was observed that the optimal concentrations of the added ligands differ between the 1.54 eV and wide-bandgap (WBG) devices. To better understand these system-dependent effects, the impact of varying ligand concentrations on device performance should be systematically discussed across the different bandgap regimes.\n6.There appears to be an inaccuracy in the caption of Figure 2. The authors should carefully verify and correct the descriptions to ensure they match the data shown."}, "author_response": "Point-by-point actions in response to the Reviewers’ comments\nWe thank the reviewers for their advice and recommendations, which have enabled us\nto improve our manuscript. Following are the detailed actions taken in light of\nreviewers’ comments.\nReviewer #1:\n[... full author response text provided in the input ...]"}, {"round": 2, "reviewer_comments": {"reviewer_1": "The authors have performed additional characterizations on the structural and defect properties of the different perovskites, which have properly addressed my previous concerns. I would recommend acceptance of the revised manuscript in Nature Communications.", "reviewer_2": "The authors have adequately responded to all my comments and revised the manuscript appropriately. The revised version meets the publication standard of the journal, and I recommend acceptance.", "reviewer_3": "The authors have addressed my concerns. I would recommend publishing this work in its current form."}, "author_response": ""}]

Decision letter