Efficient solution-processed light-emitting diodes based on organic-inorganic hybrid antimony halides

Domain: physics
Published: 2026-01-17
Editorial outcome: minor_revision

Abstract
Organic-inorganic hybrid antimony halides are emerging emitters for solution-processed light-emitting diodes. However, achieving high-efficiency electroluminescence remains challenging resulting from the non-radiative recombination within emitters and inferior charge transport within device. Here, we develop an organic cation engineering to design a carbazole-functionalized triphenyl(9-ethyl-9H-carbazol-3-yl)phosphonium (TPPEtCz+), which enables a (TPPEtCz)2Sb2Br8 film with good luminescence and achieves an improved charge transport within device. The TPPEtCz+ facilitates strong hydrogen bonding with the [Sb2Br8]2− species and dichloromethane solvent, resulting in a more complete crystal restructuring, thus improving the quality of films. Moreover, non-covalent π–π interactions between carbazole moieties of (TPPEtCz)2Sb2Br8 and benzimidazole moieties of electron-transport TPBi modify the interfacial contact that promotes electron transport and injection. Consequently, our light-emitting diodes reach a peak external quantum efficiency of 19.4% and half-lifetime of 10,190 min at 100 cd m−2. These discoveries provide critical insights into the cation design of hybrid devices that are promising for practical applications.

Introduction
Solution-processed light-emitting diodes (LEDs) are highly promising next-generation light source technology owing to their simple and low-cost fabricating processes1–5. Many types of solution-processed materials and device configurations have been developed so far, including organic LEDs6, colloidal core-shell quantum dot LEDs7, perovskite LEDs8, and organic-inorganic hybrid LEDs9. Among them, organic-inorganic hybrid metal halides are attractive because they can integrate the semiconductor properties of inorganic units and the structural diversity of organic components, which is unavailable in classical all-inorganic materials and organic chromophores10–12. Particularly, zero-dimensional (0D) hybrid antimony (Sb) halides, as a new kind of emitter in organic-inorganic material systems, are recognized for their superior photoluminescence quantum efficiency (PLQY) and stability, by virtue of their quantum-confined structure at the molecular level13–16. With strategies on designing the host-guest structures and functionalizing the organic components, the achievement of Sb halide materials for LEDs is increasingly demonstrated. Nevertheless, the highest reported external quantum efficiency (EQE) based on hybrid Sb halides is only 5.12%16, even though the corresponding PLQY of their emitters reaches an impressive 86.1%. This pronounced discrepancy between photoluminescent and electroluminescent efficiency reveal that the primary limitation lies not in the luminescent properties of the emitters, but in the inferior charge transport and injection within the device17. An additional critical factor is the serious non-radiative recombination in the Sb halide emitter due to the presence of high-density defects caused by the fast crystallization process4,15. Enhancing electroluminescence efficiency beyond current limitations is feasible via the coordinated efforts in both material and device structure design, probably through the creation of low-defect emitters and the development of advanced interfacial engineering.

In this work, we design a carbazole-functionalized triphenyl(9-ethylcarbazole) phosphonium (TPPEtCz+) cation, which not only enables the formation of (TPPEtCz)2Sb2Br8 films with good luminescence and few defects but also facilitates π–π stacking interactions with the electron-transport TPBi to modify the interfacial contact. The TPPEtCz+ is conducive to form strong hydrogen bonding with the [Sb2Br8]2− species and dichloromethane solvent, which results in a slow-release crystallization of (TPPEtCz)2Sb2Br8 films, resulting in improved surface morphology and radiative recombination. The π–π stacking interaction between the carbazole moieties of (TPPEtCz)2Sb2Br8 and the benzimidazole moieties of electron-transport TPBi also promotes the transport and injection of electrons within the device. These synergistic combinations lead to efficient Sb halide LEDs with a maximum EQE of 19.4% and a half-lifetime of 10,190 min at 100 cd m−2, representing a significant breakthrough in organic-inorganic hybrid LEDs systems.

Results
Organic cation design
We designed two similar organic cations—that is, ethyltriphenyl phosphonium (TPPEt+) and triphenyl(9-ethylcarbazole)phosphonium (TPPEtCz+), for fabricating Sb halide LEDs (Fig. 1a, b). Both cations share an identical triphenylphosphine core, but TPPEtCz+ features an additional ethylcarbazole unit within the side chain. We synthesized the carbazole-functionalized TPPEtCzBr using a substitution reaction, and their structure was validated by 1H and 13C nuclear magnetic resonance (NMR) and high-resolution mass spectral data (Supplementary Fig. 1)18–20. Based on TPPEtCzBr and TPPEtBr organic salts, we synthesized the (TPPEtCz)2Sb2Br8 (referred to as target sample) and (TPPEt)2SbBr5 (referred to as control sample) single crystals (SCs) by antisolvent vapor diffusion method21, and their crystal structures were verified using single-crystal X-ray diffraction (SCXRD) (Supplementary Fig. 2 and Supplementary Tables 1, 2). For the (TPPEt)2SbBr5, each Sb atom is bound to five Br atoms forming a square [SbBr5]2− pyramid. While two square pyramidal structures in (TPPEtCz)2Sb2Br8 are linked by edge sharing to form a [Sb2Br8]2− dimer. Differential scanning calorimetry analysis (Supplementary Fig. 3) shows that (TPPEtCz)2Sb2Br8 exhibited a melting point of 167.1 °C, emphasizing its superior thermal stability compared to (TPPEt)2SbBr5 with a melting point of 149.7 °C. The XRD patterns of (TPPEtCz)2Sb2Br8 and (TPPEt)2SbBr5 powders match well with the simulated results from SCXRD data (Supplementary Fig. 4), indicating the high phase purity of both samples.

Two Sb halide emissive layers were prepared by a spin-coating method using the same precursor solution as the preparation of SCs. The device architecture is composed of indium tin oxide (ITO)/poly(3,4 ethylene-dioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)/Sb halide/1,3,5-tri(phenyl-2-benzimi-dazolyl)-benzene (TPBi)/lithium fluoride (LiF)/aluminium (Al) (Supplementary Fig. 5). At the molecular level, both (TPPEtCz)2Sb2Br8 and TPBi contain planar π-conjugated aromatic rings of carbazole and benzimidazole moieties, respectively. Electrostatic surface potential (ESP) analysis reveals that the central regions of these aromatic rings form electron-rich (negative) centers, while the hydrogen atoms at the peripheral positions exhibit electron-deficient (positive) characteristics (Fig. 1c). These π-conjugated aromatic rings with complementary charge distribution create favorable conditions for intermolecular π−π stacking between (TPPEtCz)2Sb2Br8 and TPBi, which provides an effective pathway for enhanced charge transport18. In contrast, the ethyl-terminated surface of control (TPPEt)2SbBr5 lacks extended conjugated planes, making effective π−π interaction with TPBi highly improbable. Furthermore, the bulky TPPEtCz+ cation introduces significant steric hindrance that is expected to modulate crystallization kinetics, thereby facilitating the formation of highly uniform emissive films with improved morphological properties19.

LEDs performance
Figure 1d shows the current density−voltage−luminance curves of two LEDs. The (TPPEtCz)2Sb2Br8-based LEDs exhibit a lower turn-on voltage and higher current densities as well as luminance compared with the control device, which could be ascribed to the improved charge transport and injection. A maximum luminance of 3669 cd m−2 and a peak EQE of 19.4% were realized for (TPPEtCz)2Sb2Br8-based LEDs. By contrast, the control (TPPEt)2SbBr5-based devices had a maximum luminance of 34.0 cd m−2 and a peak EQE of only 1.1% (Fig. 1e). The high EQE for (TPPEtCz)2Sb2Br8-based LEDs represents one of the most efficient lead-free metal halide LEDs achieved so far (Fig. 1f and Supplementary Table 3). The histogram of the peak EQE for 30 devices shows an average EQE of 18.5% (Fig. 1g), indicating a reasonable reproducibility associated with the use of TPPEtCz+ cations. Supplementary Fig. 6 shows the EL spectra of two devices under various voltages, which exhibit a monotonic increase in EL intensity with a superior spectral stability. A slight redshift was detected in the EL spectra compared to the PL spectra, which might be caused by the Stark effect resulting from the electric field10.

Operational stability of two devices was evaluated at a constant current density (Fig. 1h). The device based on (TPPEtCz)2Sb2Br8 exhibited a half-lifetime (T50) of 10,190 min from an initial luminance of 100 cd m−2 (0.41 mA cm−2). This represents a substantial improvement over the control device, which showed a T50 of only 11 min at an initial luminance of 30 cd m−2 (4.32 mA cm−2). Note that this is the highest T50 reported to date for all lead-free metal halide LEDs (Supplementary Table 3), which is also significantly better than the most of thriving red-emitting perovskite LEDs (Supplementary Table 4). Furthermore, the ultraviolet-cured epoxy-encapsulated (TPPEtCz)2Sb2Br8 devices showed good storage stability, with luminance and EQE remaining stable for 30 days under ambient storage conditions (25 °C, 40−60% humidity) (Supplementary Fig. 7).

Electronic structure properties
Density functional theory calculations1,22,23 were conducted to investigate the role of organic cations in the electronic structure of the Sb-based halides. The projected density of states (pDOS) for (TPPEt)2SbBr5 indicate that the hybridized Sb 5s and Br 4p orbitals constitute the valence band maximum (VBM), whereas the conduction band minimum (CBM) originates largely from the TPPEt+ cations (Fig. 2a and Supplementary Fig. 8a). This electronic configuration results in a type-II band alignment between TPPEt+ cations and [SbBr5]2− polyhedrons (Fig. 2b), wherein the photoexcited electrons in [SbBr5]2− transfer to TPPEt+ energy levels, undergoing the non-radiative recombination via thermal vibrations24. In contrast, both VBM and CBM of (TPPEtCz)2Sb2Br8 are mainly composed of Sb and Br orbitals, while the large organic TPPEtCz+ plays a separator to isolate the inorganic [Sb2Br8]2− parts (Fig. 2c and Supplementary Fig. 8b). These results indicate that the excitons are confined on the inorganic [Sb2Br8]2− polyhedrons, which constitutes a type-I band alignment with strong exciton localization that readily favors the efficient radiative recombination25 (Fig. 2d). Electronic charge density distributions also suggest that the electron density is mostly located within [Sb2Br8]2− polyhedrons for (TPPEtCz)2Sb2Br8, while for (TPPEt)2SbBr5, part of the electron density is distributed in the organic fragment (Supplementary Fig. 9).

Photophysical properties
We investigated the influence of organic cation on the optical properties of two films. Compared with the control (TPPEt)2SbBr5 films, the absorption edge and PL peak of (TPPEtCz)2Sb2Br8 films show a slight blueshift (Fig. 2e), possibly due to the structural distortion effect of [Sb2Br8]2− dimers26. Two samples are both characterized by broadband red emission, suggesting that their luminescence originates from the self-trapped excitons (STEs)-related recombination as demonstrated in previous work27–31. We also found that the (TPPEtCz)2Sb2Br8 sample features a narrower full-width at half-maximum (FWHM) and a smaller Stokes shift than the (TPPEt)2SbBr5 (Supplementary Fig. 10), which is attributed to the weaker electron–phonon coupling and reduced lattice distortion of the (TPPEtCz)2Sb2Br8 (Supplementary Figs. 11, 12, Supplementary Tables 5, 6, and Supplementary Note 1). Note that the absolute PLQY (87.6%) of (TPPEtCz)2Sb2Br8 films was significantly improved compared to the control (TPPEt)2SbBr5 films (20.2%) (Fig. 2f and Supplementary Fig. 13), implying that the TPPEtCz+ cation enables fewer non-radiative recombination sites. Figure 2g shows the time-resolved PL spectra of two films, which can be fitted using a biexponential decay function10 (Supplementary Note 2). The fitted average lifetime of (TPPEtCz)2Sb2Br8 films is 3.57 μs, longer than that of the control counterpart (1.23 μs), which is consistent with the increased PLQY. Compared with the control films, the (TPPEtCz)2Sb2Br8 films have a smaller fraction of fast decay and a larger fraction of slow decay, evidently denoting more radiative recombination component and fewer defects using TPPEtCz+ cation. Moreover, the radiative recombination rate of (TPPEtCz)2Sb2Br8 films was estimated to be 2.45 × 107 s−1 (Supplementary Fig. 14 and Supplementary Note 3), nearly 1.5 times higher than that of the (TPPEt)2SbBr5 films (1.64 × 107 s−1), and the non-radiative recombination rate markedly decreases from 6.49 × 107 s−1 (control) to 0.35 × 107 s−1 (target) simultaneously.

Origins of luminescence enhancement
To investigate how the TPPEtCz+ cation affects the crystallization process of (TPPEtCz)2Sb2Br8 films, in-situ PL and UV-vis absorption measurements were performed during the spin-coating and annealing process (Supplementary Fig. 15)32. The initial PL peak position (<420 nm) is correlated with the organic cations. As shown in Fig. 2h, for the (TPPEt)2SbBr5, the PL intensity of TPPEt+ cations gradually decreases from the beginning of the spin-coating process, and the PL signal peaked at 680 nm from (TPPEt)2SbBr5 appears at about 3.86 s, which corresponds to the nucleation stage of [SbBr5]2− clusters (Phase I). Following closely behind is a rapid increase of PL intensity, indicating that after the crystal nucleus concentration reaches a critical value, the nuclei undergo explosive growth, corresponding to the crystal nuclei growth stage (Phase II, 0.53 s). Finally, the PL intensity shows a slow upward trend until the end of spin-coating, reflecting an enhanced crystallization via the Ostwald ripening process (Phase III, 0.67 s). In contrast, the utilization of the TPPEtCz+ cation notably delayed all three stages in the (TPPEtCz)2Sb2Br8 films, including nucleation (Phase I, 4.23 s), crystal growth (Phase II, 1.82 s), and Ostwald ripening process (Phase III, 2.63 s). This delayed crystallization process can also be validated by the in-situ UV-vis absorption spectra in Supplementary Fig. 16. During the annealing process, the in-situ PL intensities of two films decreased slightly over time without any peak shift (Supplementary Fig. 17), indicating that crystal nucleation and growth were essentially completed during the spin-coating phase, which is attributed to the rapid solvent evaporation of dichloromethane used in our experiment with a low boiling point. We employed the Avrami model to investigate the crystallization rate of (TPPEt)2SbBr5 and (TPPEtCz)2Sb2Br8 films based on the PL intensity evolution during the spin-coating process. The model is defined as kt = (−ln(1−α))1/n, where k is the effective reaction rate constant (crystallization rate constant herein), n is the Avrami exponent, t is time, and α is the conversion fraction characterized by the PL intensity of the films32. From the PL intensity-time curves (Fig. 2i), two rate constants k1 and k2 can be fitted, which k1 corresponds to the growth of the crystal nucleus, while k2 represents the Ostwald ripening process. In comparison, k1 (0.187 s−1) and k2 (0.018 s−1) values of the (TPPEtCz)2Sb2Br8 are smaller than those of the control (TPPEt)2SbBr5 (k1 = 0.246 s−1, k2 = 0.096 s−1). These specifical results show that TPPEtCz+ cations effectively retard the crystallization rate of the crystal, yielding compact films with reduced trap density and superior luminescent properties33,34. The space-charge-limited-current (SCLC) measurements35,36 (Supplementary Fig. 18 and Supplementary Note 4) show that the trap state density (Nt)37–39 of (TPPEtCz)2Sb2Br8 films is much lower than that of the control films (Supplementary Fig. 19), manifesting that the defects were effectively suppressed within (TPPEtCz)2Sb2Br8 films, in line with the enhanced PL performance.

We used NMR spectroscopy to probe the interactions between inorganic and organic components in the precursor solution to investigate the reasons for the modulation of crystallization kinetics by organic cations. The 1H NMR signals of pure TPPEtBr exhibit a downfield shift compared to (TPPEt)2SbBr5, indicating a hydrogen bond interaction between TPPEt+ and [SbBr5]2− clusters (Supplementary Fig. 20a). Importantly, the 1H NMR peaks of pure TPPEtCzBr in (TPPEtCz)2Sb2Br8 also experience a downfield shift, but with a significantly larger magnitude than that of the (TPPEt)2SbBr5 (Supplementary Fig. 20b), indicating that TPPEtCz+ has a stronger hydrogen bond interaction with [Sb2Br8]2−. This stronger hydrogen-bonding interaction slows down the crystal growth, enabling the acquisition of high-quality (TPPEtCz)2Sb2Br8 films with few defects35. 2D Hirshfeld surfaces and fingerprint plots (Supplementary Fig. 21) of two Sb halide structures show that H···Br hydrogen bonds and H···Sb interactions account for 91.5 and 3.9% of the total intermolecular interactions in (TPPEtCz)2Sb2Br8, respectively, markedly higher than those in the control (TPPEt)2SbBr5 (H···Br=85.4%, H···Sb=2%). Moreover, we examined the solvent-ligand interactions between dichloromethane (DCM) and organic components in the precursor solution. The 1H NMR results show that, compared with TPPEt+, the stronger hydrogen interaction between the carbazole moiety in TPPEtCz+ and DCM likely enhances the solvation effect (Supplementary Fig. 22), which moderates the crystallization process, working in synergy with the hydrogen-bonding effects between the organic and [Sb2Br8]2− to modulate the crystallization kinetics.

Scanning electron microscopy (SEM) images show that the control (TPPEt)2SbBr5 films exhibit a poor microscopic morphology with a heterogeneous appearance due to its rapid crystallization, while the (TPPEtCz)2Sb2Br8 films are highly dense and uniform (Supplementary Fig. 23). Atomic force microscopy (AFM) images show that the (TPPEtCz)2Sb2Br8 films present a smoother surface with a root-mean-square roughness of ~0.7 nm, significantly lower than that of the control films (~6.2 nm) (Fig. 2j). From the confocal PL mapping images (Supplementary Fig. 24a, b), the (TPPEtCz)2Sb2Br8 films display much stronger PL intensity with consistent fluorescence, which is related to better films quality and lower surface defect density that diminish the non-radiative recombination within films32. The PL lifetime imaging results also show a prolonged exciton lifetime with homogeneous distribution for (TPPEtCz)2Sb2Br8 films (Supplementary Fig. 24c, d). Grazing-incidence wide-angle X-ray scattering (GIWAXS) analysis uncovered the crystal planes alignments in the films (Fig. 2k). The appearance of Debye-Scherrer rings in the (TPPEt)2SbBr5 films indicated a random crystallographic orientation, consistent with a disordered crystalline packing. In contrast, (TPPEtCz)2Sb2Br8 films revealed a focused diffraction spot, evidencing a preferential crystalline orientation. These results suggest that the TPPEtCz+ cation is beneficial for crystal nucleation, growth, and crystallization processes, potentially improving its optoelectronic performances, which is illustrated schematically in Supplementary Fig. 25.

Carrier transport properties
As mentioned earlier, the presence of planar π–conjugated aromatic rings in both (TPPEtCz)2Sb2Br8 and TPBi creates favorable conditions for intermolecular π–π stacking, providing an effective pathway for improved charge transport. We performed Kelvin probe force microscopy (KPFM) and ultraviolet photoelectron spectroscopy (UPS) measurements40,41 to characterize the charge transport properties of two samples. A thin layer of TPBi (2 nm) was deposited on (TPPEtCz)2Sb2Br8 to probe their interfacial interaction. As shown in Fig. 3a, the average contact potential difference (VCPD) of the pure (TPPEtCz)2Sb2Br8 films was 302.6 mV, which increased significantly to 330.4 mV for TPBi-treated (TPPEtCz)2Sb2Br8 films, indicating a reduction in the work function (WF) after TPBi treatment that promotes more efficient electron injection from TPBi into the emitter layer. According to the cutoff region of the UPS spectra, the WF of TPBi-treated (TPPEtCz)2Sb2Br8 and (TPPEtCz)2Sb2Br8 films is estimated to be 4.83 and 4.88 eV, respectively (Supplementary Fig. 26b). The reduction in WF arising from the TPBi/(TPPEtCz)2Sb2Br8-induced π−π stacking facilitates the electron transport within the emitter36,39. Additionally, this interaction is associated with an upward shift in the emitter layer’s energy levels, where the VBM rises from −5.82 to −5.66 eV and the CBM from –3.26 to −3.10 eV. This collective energy level upshift optimizes the band alignment, reducing charge injection barriers and alleviating interfacial charge accumulation to enable more efficient hole and electron injection (Supplementary Fig. 26c). On the contrary, the VCPD, WF, and energy level structure of the control (TPPEt)2SbBr5 films and TPBi-treated (TPPEt)2SbBr5 films remained almost unchanged (Supplementary Fig. 27) due to the lack of π−π stacking interaction between the (TPPEt)2SbBr5 and TPBi.

Figure 3b displays the electrochemical impedance spectroscopy (EIS) of two devices. According to the equivalent circuit model, we estimated the series resistor (Rs), recombination resistor (Rrec), and capacitance (Cd) of them. The (TPPEtCz)2Sb2Br8-based devices with π−π interaction exhibit a reduction of Rs from 34 to 29 Ω, which is beneficial to the electronic charge injection and transport. Moreover, Rrec was greatly decreased from 47 to 1.4 kΩ, which facilitates the electron-hole recombination within devices. The capacitance-voltage (C-V) curves42,43 of both devices were also measured (Supplementary Note 5). The (TPPEtCz)2Sb2Br8-based LEDs have a smaller peak capacitance accompanied by a lower peak voltage compared to the control devices (Fig. 3c), revealing less traps in the emissive films. In addition, the slope of (TPPEtCz)2Sb2Br8-based LEDs in the recombination region is steeper than that of the control devices, signifying a rapid radiative recombination rate. The carrier dynamic processes of LEDs were studied by the transient EL test (Supplementary Fig. 28). (TPPEtCz)2Sb2Br8-based LEDs show a steeper upward trend at the beginning compared to the case of control devices, which manifests a rapid establishment of steady-state EL44. When the pulse voltage was deactivated, a fast EL decay was detected for (TPPEtCz)2Sb2Br8-based LEDs, which is attributed to the fewer cumulative carriers caused by balanced injection and rapid recombination45 of carriers through interfacial π−π interaction.

To gain theoretical insight into carrier dynamics, we conducted semiconductor device simulations41 of two devices. The carrier concentration profiles (Supplementary Fig. 29a, b) yield hole and electron concentrations of 1.08 × 108 cm−3 and 2.60 × 1022 cm−3, respectively, for the (TPPEt)2SbBr5-based devices. In contrast, the (TPPEtCz)2Sb2Br8-based devices show significantly higher values of 2.48 × 1011 cm−3 and 3.62 × 1023 cm−3. This indicates a more efficient and balanced charge transport in the latter system (Supplementary Fig. 29c), which benefits from the π−π interactions. Supplementary Figs. 29d, e display the simulated energy band distribution of two devices in equilibrium state, where the energy barrier of the (TPPEtCz)2Sb2Br8-based devices (φh = 0.96 eV; φe = 0.51 eV) was lower than that of the control ones (φh = 1.23 eV; φe = 0.79 eV). In addition, the calculated exciton concentration and exciton recombination rate of (TPPEtCz)2Sb2Br8-based devices were both higher than those of the control (TPPEt)2SbBr5-based devices (Supplementary Fig. 29f). These changes improve the charge carrier transport and exciton radiative recombination in the device with interfacial π−π interaction, promoting the electro-optical energy conversion, resulting in enhanced EL performance of (TPPEtCz)2Sb2Br8-based LEDs.

π−π interaction between (TPPEtCz)2Sb2Br8 and TPBi
We conducted X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and NMR measurements to reveal the mechanisms of π−π interactions between (TPPEtCz)2Sb2Br8 and TPBi. In the high-resolution XPS spectrum of N 1s (Fig. 3d), the pure (TPPEtCz)2Sb2Br8 films exhibit a single C−N peak (400.11 eV) from the carbazole moiety, while the pure TPBi films not only show C−N peak (400.60 eV) and C=N peak (398.48 eV) from benzimidazole moiety, but also display a characteristic π−π satellite peak (405.82 eV) of N-containing aromatic compounds. Importantly, in the TPBi-treated (TPPEtCz)2Sb2Br8 films, all relevant N 1s peaks, including the C−N peak of carbazole, the C−N peak and C=N peak of benzimidazole, undergo discernible shifts compared with their positions in the pure TPBi and (TPPEtCz)2Sb2Br8 films, indicating an electronic interaction between TPBi and (TPPEtCz)2Sb2Br8. Moreover, the π−π satellite peak is significantly enhanced and broadened in the TPBi-treated (TPPEtCz)2Sb2Br8 films, confirming an existence of a parallel stacking structure dominated by π−π interactions. The FTIR spectra show that the C−N and C=N stretching vibrations of TPBi-treated (TPPEtCz)2Sb2Br8 films shifted to higher wavenumbers relative to those in pure TPBi films (Fig. 3e), consistent with enhanced bond polarization resulting from π−π stacking between the conjugated benzimidazole and carbazole aromatic rings. Further confirmation of this π−π interactions is provided by proton 1H NMR spectra (Fig. 3f and Supplementary Fig. 30). The chemical shift of benzimidazole moieties in the pure TPBi was located at 7.45–7.09 ppm (labeled as H1-9), while these signals shift downfield to 7.42−7.02 ppm in the TPBi-treated (TPPEtCz)2Sb2Br8 sample. This shift arises because the protons on the planar conjugated rings involved in π−π stacking enter the shielding region generated by another aromatic ring, indicating that the induced magnetic field from the ring current of the aromatic ring opposes the external magnetic field, offsetting part of the external field and requiring a higher external magnetic field to induce proton resonance. In contrast, the protons of the carbazole moieties in (TPPEtCz)2Sb2Br8 (labeled as H10-13) show the opposite trend, with their chemical shifts move upfield from 8.17–7.85 ppm to 8.23–7.90 ppm, indicating the formation of a shielding region generated by the carbazole-conjugated moieties. Collectively, these 1H NMR results confirm that π−π interactions form via the stacking between benzimidazole (from TPBi) and carbazole (from (TPPEtCz)2Sb2Br8) moieties.

Meanwhile, the same characterizations were conducted on control (TPPEt)2SbBr5 and TPBi-treated (TPPEt)2SbBr5 samples using XPS, FTIR, and NMR measurements. As summarized in Supplementary Fig. 31, all characteristic spectral signatures of the benzimidazole unit remain unchanged in both position and linewidth across all samples, indicating the absence of any detectable interaction between ethyl moieties of (TPPEt)2SbBr5 and benzimidazole moieties of TPBi. These results further indicate that the interfacial enhancement observed in the (TPPEtCz)2Sb2Br8/TPBi system specifically arises from the π−π stacking interaction between the planar conjugated units, rather than non-specific surface contacts.

To further elucidate the π−π interactions, we theoretically studied the interaction between the TPBi layer and (TPPEtCz)2Sb2Br8. We calculated the adsorption energy (Eads) of TPBi on the (TPPEtCz)2Sb2Br8 (001) surface to identify the thermodynamically favorable stacking configuration (Fig. 3g). Specifically, three adsorption models were established, including a vertical stacking configuration with the TPBi positioned directly above the (TPPEtCz)2Sb2Br8, an in-plane parallel stacking configuration from intermolecular hydrogen bonding, and a parallel stacking configuration with the overlapping of aromatic rings of two molecules. The calculated Eads is −0.28, −0.78, and −1.61 eV (Fig. 3h), respectively, indicating that the parallel stacking configuration with overlapping aromatic rings is the thermodynamically stable arrangement. It is widely acknowledged that this parallel stacking configuration of overlapped aromatic rings stems from the intermolecular π−π interactions31, indicating an existence of π−π interactions between (TPPEtCz)2Sb2Br8 and TPBi.

We performed Independent Gradient Model (IGM) analysis to visualize the interaction pattern between (TPPEtCz)2Sb2Br8 and TPBi molecule, which can enable 3D visualization of weak non-covalent interactions. Supplementary Fig. 32a shows the sign(λ2)ρ colored isosurface maps of two systems derived from IGM analyses. We found that a broad green isosurface appears between carbazole and benzimidazole, corresponding to the sign(λ2)ρ values of –0.02~0 a.u. (Supplementary Fig. 32b), which confirms a π−π stacking interaction between them.

Demonstration of large-area LEDs
Taking advantage of the favorable surface morphology with good luminescence of (TPPEtCz)2Sb2Br8 films and improved charge transport caused by the (TPPEtCz)2Sb2Br8/TPBi π−π interaction, we further fabricated large-area red LEDs. The resulting large-area (4.5 × 4.5 cm2) (TPPEtCz)2Sb2Br8 films emit uniform and bright red emission under UV light irradiation (Fig. 4a). The PL distribution and surface roughness test demonstrates a homogeneous feature with small fluctuation throughout the entire films (Fig. 4b and Supplementary Fig. 33), illustrating an excellent uniformity. Further, large-area LEDs with an emitting area of 12.25 cm2 were achieved, exhibiting a bright red light (Fig. 4c) and outstanding electroluminescent uniformity (Fig. 4d) under forward bias. The large-area devices can reach high EQE of 17.2% and luminance of 3641 cd m−2, as well as outstanding repeatability (Fig. 4e, f).

Universal characterization
To demonstrate the universality of our proposed carbazole-functionalized organic cation strategy, other carbazole derivatives, including triphenyl(9-methyl-9H-carbazol-3-yl)phosphonium bromide (TPPMeCzBr), triphenyl(9-phenyl-9H-carbazol-3-yl)phosphonium bromide (TPPPhCzBr), and triphenyl(9-(naphthalen-2-yl)-9H-carbazol-3-yl)phosphonium bromide (TPPNaCzBr), were designed and employed to fabricate the LEDs. The structures of these carbazole derivatives are shown in Supplementary Fig. 34a. Notably, the TPPPhCz+ organic cation generates a lower delayed crystallization rate compared to the TPPMeCz+ and TPPNaCz+ systems, which contributes to a lower defect density and a higher PLQY of TPPPhCz-based Sb halide films (Supplementary Figs. 35, 36, and Supplementary Note 6). Moreover, the electron cloud distribution and ESP of the three carbazole-functionalized organic cations reveal that the TPPNaCz-based Sb halide films possess lower electrical conductivity (Supplementary Figs. 37, 38, and Supplementary Note 7). As a result, the resulting devices based on the three carbazole-functionalized organic cations exhibit slight but discernible performance differences. Specifically, the maximum luminance and EQE are 3488 cd m−2 and 17.2% for the TPPMeCz-based device, 3421 cd m−2 and 16.5% for the TPPPhCz-based device, and 3312 cd m−2 and 15.1% for the TPPNaCz-based device, respectively (Supplementary Fig. 34c−e). Despite these differences, all three carbazole derivatives-based devices significantly outperform the control TPPEt-based device, confirming the general applicability and effectiveness of the proposed strategy.

Methods
Materials
Triphenylphosphine (TPP, 99%), ethyltriphenylphosphonium bromide (TPPEtBr, 99%), 3-bromo-9-ethyl-9H-carbazole (EtCzBr, 99%), nickel bromide (NiBr2, 99.9%), PEI (80% ethoxylated solution) dichloromethane (DCM, 99.5%), chlorobenzene (anhydrous, 99.8%), dimethylformamide (DMF, anhydrous), hydrobromic acid (48%), and diethyl ether (EtO2, anhydrous) were purchased from Sigma-Aldrich. 3-bromo-9-methyl-9H-carbazole (MeCzBr, 99%), 3-bromo-9-phenyl-9H-carbazole (PhCzBr, 99%), 3-bromo-9-(2-naphthalenyl)-9H-carbazole (NaCzBr, 99%), antimony tribromide (SbBr3, 99.9%) and MoO3 (99.97%) were purchased from Aladdin. poly(ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS, AI4083), ZnO nanoparticles (ethanol, 12%), 4,4′,4″-tris(carbazol-9-yl) triphenylamine (TCTA, 99%), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi, 99.9%), and lithium fluoride (LiF, 99.99%) were purchased from Xi’an Polymer Light Technology Corp. All chemicals were used directly without any purification unless otherwise stated.

Synthesis of TPPEtCzBr
The TPPEtCzBr was synthesized according to the substitution reaction. TPP (5.24 g, 0.02 mol), EtCzBr (5.48 g, 0.02 mol) and NiBr2 (0.5 g, 0.002 mol) were added in 50 mL of ethylene glycol solution with stirring for 12 h at 170 °C. Then the deep green solution was dissolved in water and was then extracted with DCM. Et2O was used to wash the white powder product out. Yield: 98%. TPPMeCzBr, TPPPhCzBr, and TPPNaCzBr were synthesized by similar methods as mentioned above.

Growth of (TPPEt)2SbBr5 and (TPPEtCz)2Sb2Br8 single crystals
Two single crystals were synthesized via antisolvent vapor diffusion. Specifically, 0.1 mmol SbBr3 and 0.2 mmol TPPEtCzBr (or TPPEt) were mixed with 1:2 molar ratio and dissolved in 1 mL DCM to form a clear precursor solution. Then 2 mL Et2O was diffused into this precursor solution at room temperature overnight to grow Sb halide single crystals.

Device fabrication
The ITO-coated glass substrate was sequentially cleaned by sonication in acetone, ethanol, and deionized water for 15 min, respectively, and was further treated by ultraviolet ozone illumination for 20 min. Then, the PEDOT:PSS aqueous solution was spin-coating onto the substrate at 4000 rpm for 60 s in an air ambient and annealed at 135 °C for 30 min. After that, the substrate was transferred into an N2-filled glovebox. The Sb halide precursor solution made from 0.01 mmol of SbBr3 and 0.02 mmol of TPPEtCzBr (or TPPEtBr) with a molar ratio of 1:2 in 1 mL DCM was spin-coated on top at 4000 rpm for 60 s (acceleration=500 rpm s−1). The precursor concentrations of large-area devices and universal devices were 0.008 mmol mL−1 and 0.007 mmol mL−1, respectively. The spin-coated adduct films were annealed at 100 °C for 10 min. Then TPBi (30 nm), LiF (2 nm), and Al (120 nm) layers were deposited onto the luminescent films in turn by a high-vacuum organic/metal evaporation instrument under a high vacuum of ~1 × 10−4 Pa. The overlapping area of the ITO and Al electrodes was used to define the working area of the LED. The emitting area of the small-area LEDs is 0.07 cm2, while that of the large-area LEDs is 12.25 cm2. Devices for capacitance, transient EL, and electrochemical impedance study were fabricated with a device structure of ITO/PEDOT:PSS/(TPPEt)2SbBr5 or (TPPEtCz)2Sb2Br8/TPBi/LiF/Al. Hole-only and electron-only devices were fabricated using the device structures ITO/PEDOT:PSS/(TPPEt)2SbBr5 or (TPPEtCz)2Sb2Br8/TCTA/MoO3/Ag and ITO/ZnO/PEI/(TPPEt)2SbBr5 or (TPPEtCz)2Sb2Br8/TPBi/LiF/Al, respectively.

Density functional theory calculations
The generalized gradient approximation (GGA) is chosen to approximate the exchange-correlation energy with the Perdew–Burke–Ernzerhof (PBE) functional46,47. We use a cutoff energy of 400 eV and a 3 × 2 × 2 Monkhorst-Pack k-point mesh for all the calculations. The convergence threshold for each ionic step is set to be 1 × 10−5 eV, and the convergence threshold of maximum force is set to be 0.03 eV Å−1. Spin polarization is excluded in our calculations. Each configuration was optimized with the Broyden–Fletcher–Goldfarb–Shanno (BGFS) algorithm with SCF convergence criteria of 1.0 × 10−5 a.u. The van der Waals corrections of Grimme’s DFT-D3 models were also adopted. The adsorption energy between the adsorbate and the Sb halides can be calculated using the equation of ΔEads = Eadsorbate@Sbhalides − ESbhalides − Eadsorbate, where the Eadsorbate@Sbhalides and ESbhalides are the total energies of the Sb halides with and without the adsorption of the adsorbate, respectively, and Eadsorbate is the total energy of the adsorbate. According to this equation, a negative adsorption energy corresponds to a stable adsorption structure. For the ESP calculations, structures of materials were optimized using the B3LYP functional and 6–31G(d,p) basis set in the Gaussian 16 software package. The ESP images were visualized by using Multiwfn 3.8 and the Visual Molecular Dynamics (VMD) program, respectively.

Materials characterizations
1H NMR B500 is equipped with a high-resolution 5 mm TXI (H-C/N-D) Zg probe. The SC-XRD data of Sb halide SCs were measured using a Bruker D8 Venture METALJET Ga-Target SC-XRD diffractometer with Mo and Cu microfocus sealed X-ray source. The powder XRD patterns of Sb halide powders were carried out from Panalytical X’Pert Pro X-ray diffractometer equipped with Cu Kα radiation. The morphologies and surface roughness of the Sb halide films were measured by SEM (Jeol-7500F, 15 keV), in which the distribution of the elements was analyzed by element distribution (EDS) measurement. KPFM measurements were carried out using a Bruker AFM Multimode model. Synchrotron-based GIWAXS measurements were conducted at the BL14B1 beamline using X-ray with a grazing incidence angle of 0.2° and a wavelength of 1.24 Å. The diffraction patterns were collected by the Pilatus 3s 2m an exposure time of 100 s with 234 mm from the sample to the detector. FTIR spectra were tested from the Thermo Fisher Scientific Nicolet iS20 spectrometer. 1H NMR spectra were acquired on the Bruker Advanced II spectrometer. The steady-state PL and absorption spectra of the samples were tested using a steady-state PL spectrum (Horiba; Fluorolog-3) and a Shimadzu UV-3150 spectrophotometer, respectively. Time-resolved PL spectra were conducted using a fluorescence lifetime measurements system with an LED (Horiba; 280 nm). The absolute PLQY of Sb halide films was tested by using a fluorescence spectrometer (Horiba; FluoroMax-4) with an integrated sphere (Horiba; Quanta-φ). A closed-cycle helium cryostat (Jannis, using CCS-100) was used for PL measurements at different temperatures. The in-situ PL measurements of films during the spin-coating process were performed on the self-built systems (Supplementary Fig. 15) that contain excitation light sources, QE-Pro spectrometer (Ocean Optics), and optical fibers. The fluorescence and lifetime distribution imaging were performed through the fluorescence-lifetime imaging microscopy (FLIM) systems. XPS measurements were conducted using a Thermo Scientific Escalab 250Xi. UPS measurements were performed to analyze the energy band properties of Sb halides, and the UPS radiation was generated by a He-gas discharge lamp (He I = 21.22 eV).

Device characterizations
The current density-voltage-luminance, EQE, and EL spectra of LEDs were tested by using a system combining a Keithley 2400 source meter and a standard integrating sphere (FOIS-1-FL) coupled with an QE-Pro spectrometer (Ocean Optics) in a N2-filled glovebox. The performance of LEDs was double-checked using a Keithley 2400 source meter assembled with a PR705 Spectra Scan spectrophotometer (Photo Research), as shown in Supplementary Fig. 39. The EL performance of the devices provided in the main text is from integrating sphere measurement systems. The transient EL spectra were measured by the multifunctional carrier characteristic analysis system (Paios). The impedance spectroscopy and capacitance-voltage spectra of devices were tested using the Palos systems. The half-lifetime (T50) of the device was tested under continuous current operation provided by a Keithley 2400 source meter. All measurements of devices were conducted at room temperature under N2-filled glovebox.

Data availability
The data that support the findings of this study are available from the corresponding authors upon request. The crystallographic coordinates for structures reported in this paper have been deposited at the Cambridge Crystallographic Data Centre (CCDC) under deposited number CCDC: 2512568 ((TPPEt)2SbBr5) and 2513340 ((TPPEtCz)2Sb2Br8), which can be accessible via this link https://www.ccdc.cam.ac.uk/structures/. Source data are provided with this paper.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "This manuscript reports high-performance red LEDs based on a 0D organic-inorganic antimony halide (TPPEtCz)2Sb2Br8,\nachieving an impressive EQE of 19.4%. The authors attribute the improvement to the use of a semiconducting carbazole-\nfunctionalized organic cation. However, the core concept and material design were already published in Advanced\nMaterials in 2023 (reference 16 in the manuscript), where a nearly identical compound, TPPcarzSbBr4 (the same as\n(TPPPhCz)2Sb2Br8 in this work), was introduced and demonstrated as a red emitter. The present study very much reused\nthe same strategy, but claimed a record EQE of 19.4% for (TPPEtCz)2Sb2Br8 based devices and ~17% for\n(TPPPhCz)2Sb2Br8, substantially higher than the ~5% reported for the same material in reference 16. The manuscript does\nnot address or explain this discrepancy, raising serious concerns about novelty, clarity, and consistency.", "reviewer_2": "In this manuscript, the authors present a comprehensive study on antimony halide hybrid systems with carbazole-\nfunctionalized organic cations. Their work demonstrates the critical role of carbazole-based TPPEtCz+ organic cations in\nfacilitating high-quality film formation, suppressing non-radiative recombination, and enhancing electrical conductivity.\nFurthermore, the fabricated antimony halide-based LED devices achieve a record-high external quantum efficiency and an\nextended half-lifetime, representing a significant advancement in the metal halide LED field. While the manuscript is well-\nstructured and merits publication in Nature Communications, some conclusions require additional clarification and\nexperimental evidence.\n1. The authors attribute the slowed crystallization rate of (TPPEtCz)2Sb2Br8 films to TPPEtCz+ cations. However, the\nunderlying mechanism remains unclear. Could the authors provide further discussion or experimental evidence to elucidate\nhow these organic cations modulate crystallization kinetics?\n2. A red shift is observed in the electroluminescence spectra (Supplementary Fig. 5) compared to the photoluminescence\nspectra (Fig. 2e). What causes this discrepancy?\n3. The turn-on voltage (more than 6 V) for large-area devices based on (TPPEtCz)2Sb2Br8 appears relatively high\n(Supplementary Fig. 19a). This phenomenon is also observed in the other carbazole-derived LEDs. What underlying factors\ncontribute to these high turn-on voltages in the large-area devices and carbazole-derived systems?\n4. The authors state that “For the (TPPEt)2SbBr5, the calculated projected density of states (pDOS) show that the top of\nbandgap consists mainly of the valence band maximum (VBM) of Sb 5s and Br 4p orbitals, while the bottom of bandgap is\ncomposed of the lowest unoccupied molecular orbital (LUMO) of TPPEt+ (Fig. 2a and Supplementary Fig. 7a).” However, it\nshould be noted that both the VBM and LUMO are calculated for the properties of the entire (TPPEt)2SbBr5 system and\ncannot be meaningfully assigned to individual fragments such as TPPEt+ or SbBr52-. Therefore, the statement of “the lowest\nunoccupied molecular orbital (LUMO) of TPPEt+” and HOMO, LUMO, VBM, CBM labeled in Fig.2a-d are very confusing.\nThe authors need to clarify this statement and ensure that the type I or type II semiconductor of these hybrids are consistent\nwith the definition in the heterostructure semiconductors.", "reviewer_3": "Referee’s Report\nIn this study, Zhuangzhuang Ma et al. present a report on promising solution processed zero-dimensional hybrid antimony (Sb) based emitters for highly-efficient LEDs, demonstrating a promising approach towards lead-free high-performance\noptoelectronic devices. This study represents a significant and important breakthrough in the field of zero-dimensional organic-inorganic hybrid LED systems and is therefore highly relevant and interesting in this field. However, the reviewer\nsuggests the authors consider the following points for strengthening the manuscript prior to publication in Nature\nCommunications.\naddition to the Cu, Mn, and Sb-based systems presented by the authors, numerous studies on other metal halides (e.g., Sn-\nbased) have also been reported. It is therefore suggested that such examples be included in Fig. 1f of the main text or in a\nsupplementary table.\nseveral minutes to several tens of minutes. Such intervals may not be sufficient to accurately assess the true operational\nstability of the devices. In addition, the measurement intervals for the control device and the target device also appear to\ndiffer. For greater clarity and reliability, the operational stability results should be presented with consistent and clearly\ndefined measurement intervals. In addition, the current densities of the control device and the target device at each\nluminance value (specified in the main text as 100 and 30 cd/m2) are also expected to differ, and these values should be\nclearly presented as well.\nLEDs? It would also be beneficial to present the actual device parameters alongside the relative luminance values: for\nexample, the measurement voltage, the corresponding luminance, EQE, and other parameters.\nCould the authors provide a possible explanation for this observation? In addition, the target sample seems to exhibit a\nlarger Stokes shift. It would be helpful if the authors could provide an explanation for these observations.\nthe inherently strong PL emission of the organic material itself? Furthermore, according to the experimental section, the spin-\ncoating time is reported as 60 sec with an acceleration rate of 500 rpm/s, whereas the data presented in Fig. 2h only\ncovers the first 8 sec. Information on the subsequent time period is also important. How do the crystallization process and optical\nproperties evolve beyond this point? In addition, please provide the optical properties before and after annealing for a more\ncomplete understanding.\nappropriate; however, the transition to the final section on “Universality characterization” could be made more seamless. If\nthe authors wish to present this part in the main figures, it is recommended that they provide a detailed explanation for\nintroducing the additional analogous derivatives, or alternatively, consider addressing this content in the supplementary\nfigures and notes. Furthermore, it is advised to include a detailed discussion on the observed differences in PLQY and\nconductivity among the derivatives, as well as a comprehensive explanation of the performance variations of devices\nincorporating each carbazole-functionalized organic cation.\ni. The red labeling in Fig. 1h, shown as (TPPEtCz)2Sb2Br5, appears to be incorrect. It seems more likely that it should be\n(TPPEtCz)2Sb2Br8. The authors are kindly requested to verify this point.\nii. The emission and absorption spectra of the two emitters appear to differ (Fig. 2e). Could the authors provide the EL\nspectrum of (TPPEt)2SbBr5? If the bandgaps of the two emitters are indeed different, then the energy level diagram\npresented in Supplementary Fig. 17 should also reflect this difference. The authors are therefore requested to clarify this\npoint.\niii. On page 19, in the Device Fabrication section (line 312), the text states “onto the substrate at 4000 rmp for 60s.” This\nappears to be a typo and should be corrected to “4000 rpm” In addition, it would be helpful for clarity and reproducibility if the\ndefined device area is explicitly specified in this section.\niv. In the Device Characterizations section, it is stated that LED performance was measured using an integrating sphere and\na QD-Pro spectrometer, and further double-checked with a PR705 spectrophotometer. Could the authors clarify whether the\ndevice performance data presented in the main text are those obtained from the integrating sphere measurements? In\naddition, it is recommended that the double-checked data also be included in the supplementary Figure, as this would\nprovide stronger validation of the reported device performance.\nWe hope the authors find these comments constructive and helpful in further improving the manuscript."}, "author_response": "Point-by-point response\n(NCOMMS-25-52674-T)\nWe are grateful for the reviewers’ time and efforts in providing us with detailed and\nconstructive comments. These suggestions are greatly helpful to us in improving the quality\nof this work. We have addressed all the concerns raised by the reviewer point-by-point as\nfollows. All changes in the revised manuscript are highlighted with a yellow for clarity.\nReviewer #1 (Remarks to the Author):\nThis manuscript reports high-performance red LEDs based on a 0D organic-inorganic\nantimony halide (TPPEtCz) Sb Br , achieving an impressive EQE of 19.4%. The authors\n2 2 8\nattribute the improvement to the use of a semiconducting carbazole-functionalized organic\ncation. However, the core concept and material design were already published in Advanced\nMaterials in 2023 (reference 16 in the manuscript), where a nearly identical compound,\nTPPcarzSbBr (the same as (TPPPhCz) Sb Br in this work), was introduced and\n4 2 2 8\ndemonstrated as a red emitter. The present study very much reused the same strategy, but\nclaimed a record EQE of 19.4% for (TPPEtCz) Sb Br based devices and ~17% for\n2 2 8\n(TPPPhCz) Sb Br , substantially higher than the ~5% reported for the same material in\n2 2 8\nreference 16. The manuscript does not address or explain this discrepancy, raising serious\nconcerns about novelty, clarity, and consistency.\nResponse: We sincerely thank the reviewer for carefully reading our manuscriptand valuable\nfeedback. We apologize for the lack of clarity in the original manuscript regarding the\nelectroluminescence performance discrepancy between our work and previously reported\nsystem, which has understandably raised your concerns. We would like to take the\nopportunity to elaborate in detail on the novelty, clarity and consistency of our work, which\nhave substantially improved the quality of our manuscript. We sincerely hope that the\nreviewer will find the Revised Manuscript suitable for publication in Nature\nCommunications.\nAs rightly mentioned by the reviewer, there exists a significant difference in device\nperformance between our (TPPEtCz) Sb Br and the previously reported TPPcarzSbBr\n2 2 8 4\n1\nsystem (Adv. Mater. 35, 2209417, 2023), where our LEDs achieved a substantially higher\nEQE of 19.4%, vastly outperforming the reported value of 5.12%. This device performance\ngap exists despite comparable PLQYs (86.1% for reported TPPcarzSbBr and 87.6% for our\n4\n(TPPEtCz) Sb Br ), indicating that the primary limitation in this system lies not in the\n2 2 8\nluminescent properties of emitter, but in the inefficient charge transport and injection under\nelectrical conditions, which is likely the main reason for the low EQE in the previous system.\nWe effectively address this bottleneck through interfacial modulation enabled by the π−π\ninteraction between the TPPEtCz⁺ organic cation and the TPBi, which is fundamentally\ndifferent from the previous study that only focused on optimizing the TPPcarzSbBr itself.\nefficiency, charge transport efficiency, and light out-coupling efficiency (Nat. Rev. Mater. 7,\n757, 2022). Given the similar PLQY and light out-coupling conditions in both systems, we\nattribute the superior EQE in our devices to markedly improved charge transport and\ninjection. We note that ZnO was used as the electron transport layer in the referenced\nliterature (Fig. R1a), while TPBi was used as the electron transport layer in our device\nstructure (Fig. R2a), and hole transport layers in two device structures are basically the same.\nWe compared the electrochemical impedance spectroscopy of TPBi-based (our work from\noriginal manuscript) and ZnO-based (Copied from Adv. Mater. 35, 2209417, 2023) devices to\nclarify the charge transport and injection dynamics. According to the equivalent circuit fitting\nresults (Fig. R1b and Fig. R2b), the series resistance (R ) and transport capacitance (C ) of\ns d\nTPBi-based device (R = 29 Ω; C = 1.6 nF) are reduced by more than one order of magnitude\ns d\ncompared with ZnO-based device (R = 839.8 Ω; C = 16.79 nF), indicating significantly\ns d\nimproved charge transport and injection in our device. Furthermore, the current density of the\nelectron-only device based on TPBi layer is higher than that based on ZnO layer (Fig. R1c\nand Fig. R2c), approaching that of the hole-only device, which manifests the capacity of\nTPBi on enhancing and balancing the charge carriers in the device.\nBecause the intrinsic electron mobility of ZnO is higher than that of TPBi (Adv. Funct. Mater.\n29, 1902008, 2019), we reasonably infer that TPBi and (TPPEtCz) Sb Br may not be a\n2 2 8\nsimple physical contact, but there is an interaction that promotes charge transport. Inspired by\n2\nthe reviewer’s feedback, we conducted an in-depth analysis of the (TPPEtCz) Sb Br /TPBi\n2 2 8\ninterfacial interactions and proposed that the spontaneous (TPPEtCz) Sb Br /TPBi π−π\n2 2 8\ninteraction plays a critical role in achieving high device efficiency (Fig. R3). This interaction\noccurs between the carbazole moieties of (TPPEtCz) Sb Br and the benzimidazole moieties\n2 2 8\nof TPBi, which will be discussed in detail later. This non-covalent interaction effectively\nbridges the interface between (TPPEtCz) Sb Br and TPBi, thereby modifying the interfacial\n2 2 8\ncontact, promoting electron transport and injection, and facilitating an efficient exciton\nrecombination. Notably, in the reported reference, the ZnO electron transport layer is a\nphysical contact with the emitters, without involving such an interfacial interaction\nmechanism. Therefore, this interfacial π−π interaction is a decisive advance in translating\nhigh PLQY of emitter into the superior electroluminescence performance of device. The\ndesign of the carbazole-functionalized TPPEtCz+ organic cation enables this beneficial π−π\ninterfacial interaction, which represents the novelty of our work.\nFigure R1. a, Device architecture with a heterostructure of\nITO/PEDOT:PSS/PVK/TPPcarzSbBr /ZnO/LiF/Al. b, Electrochemical impedance\n4\nspectroscopy of devices based on TPPcarzSbBr films. c, Current density−voltage curve\n4\nbased on electron-only device. Copied from Adv. Mater. 35, 2209417 (2023).\nITO/PEDOT:PSS/(TPPEtCz) Sb Br /TPBi/LiF/Al. b, Electrochemical impedance\n2 2 8\nspectroscopy of devices based on (TPPEtCz) Sb Br films. c, Current density−voltage curve\n2 2 8\nbased on electron-only device. These results come from our original manuscript.\nFigure R3. a,b, Schematic diagram of device structure based on control (TPPEt) SbBr (a)\n2 5\nand target (TPPEtCz) Sb Br (b) emitters, highlighting the chemical structures of organic\n2 2 8\ncation and interfacial interaction between emitters and TPBi.\nRevisions: The following sentences have been modified in the abstract, introduction and\nconclusion sections of the Revised Manuscriptto highlight the novelty of our work.\nOn Page 2, line 26–30: “The bulky TPPEtCz+ facilitates strong hydrogen bonding with the\n[Sb Br ]2− species, resulting in a more complete crystal restructuring, thus improving the\n2 8\nquality of (TPPEtCz) Sb Br films. Moreover, non-covalent π–π interactions between\n2 2 8\ncarbazole moieties of (TPPEtCz) Sb Br and benzimidazole moieties of electron-transport\n2 2 8\nTPBi modify the interfacial contact that promotes electron transport and injection.”\nOn Page 3, line 48–57: “Nevertheless, the highest reported external quantum efficiency (EQE)\nbased on hybrid Sb halides is only 5.12%16, even though the corresponding PLQY of their\nemitters reaches an impressive 86.1%. This pronounced discrepancy between\nphotoluminescent and electroluminescent efficiency reveals that the primary limitation lies\nnot in the luminescent properties of the emitters, but in the inferior charge transport and\ninjection within the device17. An additional critical factor is the serious non-radiative\nrecombination in Sb halide emitter due to the presence of high-density defects caused by the\nfast crystallization process15,18. Overcoming the limitation of electroluminescence efficiency\ncould be achieved by designing new emitters with low-density defects on the material side\nand developing advanced interfacial engineering at the device level.”\nOn Page 4, line 59–66: “which not only enables the formation of the novel (TPPEtCz) Sb Br\n2 2 8\nfilms with good luminescence and few defects but also facilitates π–π stacking interactions\nwith the electron-transport TPBi to modify the interfacial contact. The bulky TPPEtCz+ is\nconducive to form strong hydrogen bonding with the [Sb Br ]2− species, which enables a\n2 8\nslow-release crystallization of (TPPEtCz) Sb Br films, resulting in improved surface\n2 2 8\nmorphology and radiative recombination. The π–π stacking interaction between the\n4\ncarbazole moieties of (TPPEtCz) Sb Br and the benzimidazole moieties of electron-transport\n2 2 8\nTPBi also promotes the transport and injection of electrons within the device.”\nOn Page 23, line 417–420: “Concurrently, the π–π interaction between the carbazole moieties\nof (TPPEtCz) Sb Br and the benzimidazole moieties of TPBi effectively regulated the\n2 2 8\n(TPPEtCz) Sb Br /TPBi interface, promoting the transport and injection of electrons within\n2 2 8\nthe device.”\nTo support our conclusions, we have conducted additional experiments and theoretical\nanalyses and have carefully revised the manuscript. The detailed analyses of π−π interaction\nat (TPPEtCz) Sb Br /TPBi interface are listed below:\n2 2 8\n1) Theoretical insights into π−π interaction at (TPPEtCz) Sb Br /TPBi interface\n2 2 8\nWe systematically investigated the mechanisms underlying the enhanced charge transport\nattributed to the π−π interaction at the (TPPEtCz) Sb Br /TPBi interface. From a molecular\n2 2 8\npoint of view, the molecular structures of (TPPEtCz) Sb Br and TPBi have planar\n2 2 8\nπ−conjugated aromatic rings of carbazole and benzimidazole, respectively. Electrostatic\nsurface potential (ESP) analysis reveals that the central regions of these aromatic rings form\nelectron-rich (negative) centers, while the hydrogen atoms at the peripheral positions exhibit\nelectron-deficient (positive) characteristics (Fig. R4). These π−conjugated aromatic rings\nwith complementary charge distribution create favorable conditions for intermolecular π−π\nstacking between (TPPEtCz) Sb Br and TPBi, which provides an effective pathway for\n2 2 8\nenhanced charge transport (Adv. Mater. 37, e05597, 2025). In contrast, the ethyl-terminated\nsurface of the control (TPPEt) SbBr lacks extended conjugated planes, making effective π−π\n2 5\ninteraction with TPBi highly improbable.\nFigure R4. Electrostatic surface potential of (TPPEt) SbBr , TPBi, and (TPPEtCz) Sb Br .\n2 5 2 2 8\nTPBi layer and (TPPEtCz) Sb Br . We calculated the adsorption energy (E ) of TPBi on the\n2 2 8 ads\n(TPPEtCz) Sb Br (001) surface to identify the thermodynamically favorable stacking\n2 2 8\nconfiguration (Fig. R5a). Specifically, three adsorption models were established, including a\nvertical stacking configuration with the TPBi positioned directly above the (TPPEtCz) Sb Br ,\n2 2 8\nan in-plane parallel stacking configuration from intermolecular hydrogen bonding, and a\nparallel stacking configuration with overlapping of aromatic rings of two molecules. The\ncalculated E is −0.28, −0.78, and −1.61 eV (Fig. R5b), respectively, indicating that the\nads\nparallel stacking configuration with overlapping aromatic rings is the thermodynamically\nstable arrangement. It is widely acknowledged that this parallel stacking configuration of\noverlapped aromatic rings stems from the intermolecular π−π interactions (Nano Lett. 25,\n5957, 2025), indicating an existence of π−π interactions between (TPPEtCz) Sb Br and\n2 2 8\nTPBi.\nWe performed Independent Gradient Model (IGM) analysis to visualize the interaction\npattern between (TPPEtCz) Sb Br and TPBi molecule, which can enable 3D visualization of\n2 2 8\nweak non-covalent interactions. Fig. R5c shows the sign(λ )ρ colored isosurface maps of two\n2\nsystem derived from IGM analyses. We found that a broad green isosurface appears between\ncarbazole and benzimidazole, corresponding to the sign(λ )ρ values of –0.02~0 a.u. (Fig.\n2 2 8\nComparison of adsorption energies of three adsorption models. c, Visualization of π−π\nstacking interaction between TPBi and (TPPEtCz) Sb Br by the independent gradient model\n2 2 8\n(IGM) analysis. d, Scatter diagram of the δ isosurface versus sign(λ )ρ in this system.\ng 2\nRevisions: The following sentences have been added in the Revised Manuscriptto emphasize\nthe mechanisms of the π−π interaction between (TPPEtCz) Sb Br and TPBi.\n2 2 8\nOn Page 7, line 99–110: “At the molecular level, both (TPPEtCz) Sb Br and TPBi contain\n2 2 8\nplanar π−conjugated aromatic rings of carbazole and benzimidazole moieties, respectively.\nElectrostatic surface potential (ESP) analysis reveals that the central regions of these\naromatic rings form electron-rich (negative) centers, while the hydrogen atoms at the\nperipheral positions exhibit electron-deficient (positive) characteristics (Fig. 1c). These\nπ−conjugated aromatic rings with complementary charge distribution create favorable\nconditions for intermolecular π−π stacking between (TPPEtCz) Sb Br and TPBi, which\n2 2 8\nprovides an effective pathway for enhanced charge transport19 (Fig. 1b). In contrast, the\nethyl-terminated surface of the control (TPPEt) SbBr lacks extended conjugated planes,\n2 5\nmaking effective π−π interaction with TPBi highly improbable (Fig. 1a). Furthermore, the\nbulky TPPEtCz+ cation introduces significant steric hindrance that is expected to modulate\ncrystallization kinetics, thereby facilitating the formation of highly uniform emissive films\nwith improved morphological properties20.”\nOn Page 20, line 357–374: “To further elucidate the π−π interactions, we theoretically\nstudied the interaction between the TPBi layer and (TPPEtCz) Sb Br . We calculated the\n2 2 8\nadsorption energy (E ) of TPBi on the (TPPEtCz) Sb Br (001) surface to identify the\nads 2 2 8\nthermodynamically favorable stacking configuration (Fig. 3g). Specifically, three adsorption\n7\nmodels were established, including a vertical stacking configuration with the TPBi positioned\ndirectly above the (TPPEtCz) Sb Br , an in-plane parallel stacking configuration from\n2 2 8\nintermolecular hydrogen bonding, and a parallel stacking configuration with overlapping of\naromatic ringsof two molecules. The calculated E is −0.28, −0.78, and −1.61 eV (Fig. 3h),\nads\nrespectively, indicating that the parallel stacking configuration with overlapping aromatic\nrings is the thermodynamically stable arrangement. It is widely acknowledged that this\nparallel stacking configuration of overlapped aromatic rings stems from the intermolecular\nπ−π interactions33, indicating an existence of π−π interactions between (TPPEtCz) Sb Br\n2 2 8\nand TPBi. We performed Independent Gradient Model (IGM) analysis to visualize the\ninteraction pattern between (TPPEtCz) Sb Br and TPBi molecule, which can enable 3D\n2 2 8\nvisualization of weak non-covalent interactions. Supplementary Fig. 31a shows the sign(λ )ρ\n2\ncolored isosurface maps of two systems derived from IGM analyses. We found that a broad\ngreen isosurface appears between carbazole and benzimidazole, corresponding to the\nsign(λ )ρ values of –0.02~0 a.u. (Supplementary Fig. 31b), which confirms a π−π stacking\n2\ninteractionbetween them.”\nPage 5: Figs. 1a–c were replaced by new figures.\nPage 15: Fig. 3 was replaced by new figure.\nSupplementary Fig. 31 was added in the Supporting Information.\n2) Experimental demonstrations of π−π interaction between (TPPEtCz) Sb Br and\n2 2 8\nTPBi\nWe conducted the X-ray photoelectron spectroscopy (XPS), Fourier transform infrared\nspectroscopy (FTIR), and nuclear magnetic resonance (NMR) measurements to reveal the\nmechanisms of π−π interactionsbetween (TPPEtCz) Sb Br and TPBi. In the high-resolution\n2 2 8\nXPS spectrum of N 1s (Fig. R6a), the pure (TPPEtCz) Sb Br films exhibit a single C−N\n2 2 8\npeak (400.11 eV) from carbazole moiety, while the pure TPBi films not only show C−N peak\n(400.60 eV) and C=N peak (398.48 eV) from benzimidazole moiety, but also display a\ncharacteristic π−π satellite peak (405.82 eV) of N-containing aromatic compounds.\nImportantly, in the TPBi-treated (TPPEtCz) Sb Br films, all relevant N 1s peaks, including\n2 2 8\nthe C−N peak of carbazole, the C−N peak and C=N peak of benzimidazole, undergo\ndiscernible shifts compared with their positions in the pure TPBi and (TPPEtCz) Sb Br films,\n2 2 8\nindicating an electronic interaction between (TPPEtCz) Sb Br and TPBi. Moreover, the π−π\n2 2 8\nsatellite peak is significantly enhanced and broadened in the TPBi-treated (TPPEtCz) Sb Br\n2 2 8\nfilms, confirming an existence of the parallel stacking structure dominated by π−π\ninteractions.\n(TPPEtCz) Sb Br films shiftedhigher wavenumbers relative to those in pure TPBi films (Fig.\n2 2 8\nR6b), consistent with enhanced bond polarization resulting from π−π stacking between the\nconjugated benzimidazole and carbazole rings.\nFurther confirmation of this π−π interaction is provided by proton 1H NMR spectra (Fig.\nR6c). The 1H chemical shift of benzimidazole moieties in the pure TPBi was located at\n7.45−7.09 ppm (labeled as H ), while these signals shift downfield to 7.42−7.02 ppm in the\n1−9\nTPBi-treated (TPPEtCz) Sb Br sample.This shift arises because the protons on the planar\n2 2 8\nconjugated rings involved in π−π stacking enter the shielding region generated by another\naromatic ring, indicating that the induced magnetic field from the ring current of the aromatic\nring opposes the external magnetic field, offsetting part of the external field and requiring a\nhigher external magnetic field to induce proton resonance. In contrast, the protons of the\ncarbazole moieties in (TPPEtCz) Sb Br (labeled as H ) show the opposite trend, with\n2 2 8 10–13\ntheir 1H chemical shifts move upfield from 8.17–7.85 ppm to 8.23–7.90 ppm, indicating the\nformation of a shielding region generated by the carbazole-conjugated moieties. Collectively,\nthese 1H NMR results confirm that π−π interactions form via the stacking between\nbenzimidazole (from TPBi) and carbazole (from (TPPEtCz) Sb Br ) moieties.\n2 2 8\nC=N C-N\n396 399 402 405 408\nBinding energy (eV)\nπ−π stacking\n404 406 408\nFigure R6. a–c, N 1s fine spectra (a), FTIR spectra (b), and 1H NMR spectra (c) of pure\nTPBi, TPBi-treated (TPPEtCz) Sb Br , and pure (TPPEtCz) Sb Br . d–f, N 1s fine spectra\n2 2 8 2 2 8\n(d), FTIR spectra (e), and 1H NMR spectra (f) of pure TPBi, TPBi-treated (TPPEt) SbBr ,\n2 5\nand pure (TPPEt) SbBr . g, 1H peaks is characteristic of H and H as labelled in the\n2 5 10–13 1−9\nmolecular structure of TPPEtCzBr, TPBi, and TPPEtBr.\nMeanwhile, the same characterizations were conducted on control (TPPEt) SbBr and\n2 5\nTPBi-treated (TPPEt) SbBr samples using XPS, FTIR, and NMR measurements. As\n2 5\nsummarized in Figs. R6d−f, all characteristic spectral signatures of the benzimidazole unit\nremain unchanged in both position and linewidth across all samples, indicating the absence of\nany detectable interaction between ethyl moieties of (TPPEt) SbBr and benzimidazole\n2 5\nmoieties of TPBi. This result further confirms that the interfacial enhancement observed in\n10\n).u.a(\nytisnetni\nSPX\nπ−π stacking\n(TPPEtCz)2Sb2Br8\nTPBi-treated (TPPEtCz)2Sb2Br8\nTPBi\n396 399 402 405 408\n).u.a(\nytisnetni\nSPX\n1600 1500 1400 1300 1200 1100\nπ−π stacking\n(TPPEt)2SbBr5\nTPBi-treated\n(TPPEt)2SbBr5\nTPBi\nC=N C-N\nBinding energy (eV)\n).u.a(\nytisnetnI\nTPBi TPBi-treated (TPPEtCz)2Sb2Br8\n(TPPEtCz)2Sb2Br8\n1276.6 1492.0 C=N C-N\n1282.7\n1497.5\n1293.1\nWavenumber (cm-1)\n1600 1500 1400 1300 1200 1100\n).u.a(\nytisnetnI C-N\nC=N TPBi\nTPBi-treated (TPPEt)2SbBr5\n(TPPEt)2SbBr5\n8.5 8.0 7.5 7.0 6.5\nWavenumber (cm-1)\n).u.a(\nytisnetnI\n8.5 8.0 7.5 7.0 6.5\nTPBi\nH1-9\nTPBi-treated\n(TPPEt)2SbBr5\nH14-16 (TPPEt)2SbBr5\nChemical shift (ppm)\n).u.a(\nytisnetnI\na b c\nπ−π stacking TPBi\nH1-9\nTPBi-treated (TPPEtCz)2Sb2Br8\nH10-13 (TPPEtCz)2Sb2Br8\n404 406 408\nChemical shift (ppm)\nd e f\ng\n14\n15\nTPPEtCz+ TPBi TPPEt+\nthe (TPPEtCz) Sb Br /TPBi system specifically arises from the π−π stacking interaction\n2 2 8\nbetween the planar conjugated units, rather than non-specific surface contacts.\nRevisions: The following sentences have been added in the Revised Manuscriptto emphasize\nthe mechanisms of the π−π interaction between (TPPEtCz) Sb Br and TPBi.\n2 2 8\nOn Page 18–20 line 320–356: “We conducted the X-ray photoelectron spectroscopy (XPS),\nFourier transform infrared spectroscopy (FTIR), and NMR measurements to reveal the\nmechanisms of π−π interactionsbetween (TPPEtCz) Sb Br and TPBi. In the high-resolution\n2 2 8\nXPS spectrum of N 1s (Fig. 3d), the pure (TPPEtCz) Sb Br films exhibit a single C−N peak\n2 2 8\n(400.11 eV) from carbazole moiety, while the pure TPBi films not only show C−N peak\n(400.60 eV) and C=N peak (398.48 eV) from benzimidazole moiety, but also display a\ncharacteristic π−π satellite peak (405.82 eV) of N-containing aromatic compounds.\nImportantly, in the TPBi-treated (TPPEtCz) Sb Br films, all relevant N 1s peaks, including\n2 2 8\nthe C−N peak of carbazole, the C−N peak and C=N peak of benzimidazole, undergo\ndiscernible shifts compared with their positions in the pure TPBi and (TPPEtCz) Sb Br films,\n2 2 8\nindicating an electronic interaction between TPBi and (TPPEtCz) Sb Br . Moreover, the π−π\n2 2 8\nsatellite peak is significantly enhanced and broadened in the TPBi-treated (TPPEtCz) Sb Br\n2 2 8\nfilms, confirming an existence of the parallel stacking structure dominated by π−π\ninteractions. The FTIR spectra shows that the C−N and C=N stretching vibrations of\nTPBi-treated (TPPEtCz) Sb Br films shiftedhigher wavenumbers relative to those in pure\n2 2 8\nTPBi films (Fig. 3e), consistent with enhanced bond polarization resulting from π−π stacking\nbetween the conjugated benzimidazole and carbazole aromatic rings. Further confirmation of\nthis π−π interaction is provided by proton 1H NMR spectra (Fig. 3f and Supplementary Fig.\n29). The chemical shift of benzimidazole moieties in the pure TPBi was located at 7.45−7.09\nppm (labeled as H ), while these signals shift downfield to 7.42−7.02 ppm in the\n1−9\nTPBi-treated (TPPEtCz) Sb Br sample.This shift arises because the protons on the planar\n2 2 8\nconjugated rings involved in π−π stacking enter the shielding region generated by another\naromatic ring, indicating that the induced magnetic field from the ring current of the\naromatic ring opposes the external magnetic field, offsetting part of the external field and\nrequiring a higher external magnetic field to induce proton resonance. In contrast, the\nprotons of the carbazole moieties in (TPPEtCz) Sb Br (labeled as H ) show the opposite\n2 2 8 10–13\ntrend, with their chemical shifts move upfield from 8.17–7.85 ppm to 8.23–7.90 ppm,\nindicating the formation of a shielding region generated by the carbazole-conjugated\nmoieties. Collectively, these 1H NMR results confirm that π−π interactions form via the\nstacking between benzimidazole (from TPBi) and carbazole (from (TPPEtCz) Sb Br )\n2 2 8\nmoieties. Meanwhile, the same characterizations were conducted on control (TPPEt) SbBr\n2 5\nand TPBi-treated (TPPEt) SbBr samples using XPS, FTIR, and NMR measurements. As\n2 5\nsummarized in Supplementary Fig. 30, all characteristic spectral signatures of the\nbenzimidazole unit remain unchanged in both position and linewidth across all samples,\nindicating the absence of any detectable interaction between ethyl moieties of (TPPEt) SbBr\n2 5\nand benzimidazole moieties of TPBi. These results further indicate that the interfacial\nenhancement observed in the (TPPEtCz) Sb Br /TPBi system specifically arises from the π−π\n2 2 8\n11\nstacking interaction between the planar conjugated units, rather than non-specific surface\ncontacts.”\nSupplementary Figs. 29, 30 were added in the Supporting Information.\n3) Influence of π−π interaction on charge transport\nWe supplemented kelvin probe force microscopy (KPFM) and ultraviolet photoelectron\nspectroscopy (UPS) measurements to characterize the charge transport properties of two\nsamples. As shown in Fig. R7a, the average contact potential difference (V ) of the pure\nCPD\n(TPPEtCz) Sb Br films was 302.6 mV, which increased significantly to 330.4 mV for\n2 2 8\nTPBi-treated (TPPEtCz) Sb Br films. This increase in V indicates a reduced work\n2 2 8 CPD\nfunction (W ) in the TPBi-treated (TPPEtCz) Sb Br compared to the pure (TPPEtCz) Sb Br ,\nF 2 2 8 2 2 8\npromoting more efficient electron injection from TPBi to the emitter layer (Appl. Phys. Lett.\n120, 243501, 2022). According to the cutoff region of the UPS spectra, the W of\nF\nTPBi-treated (TPPEtCz) Sb Br and (TPPEtCz) Sb Br films is estimated to be 4.83 and 4.88\n2 2 8 2 2 8\neV, respectively (Fig. R7b). The reduction of the W caused by π−π stacking interaction\nF\nfavors the electron transport of emitter layer, which is consistent with previous reports (Light\nSci. Appl. 14, 285, 2025; Adv. Funct. Mater. 34, 2402522, 2024). In addition, the VBM of\n(TPPEtCz) Sb Br films is increased from −5.82 eV to −5.66 eV, and the corresponding CBM\n2 2 8\nis increased from –3.26 eV to −3.10 eV (Fig. R7b). The overall upward shift of the energy\nlevel of the emitter layer matched better with the energy levels of the transport layers, thus\nreducing the injection barrier and charge accumulation at the interface, which is conducive to\nthe faster injection of both hole and electron (Fig. R7c). On the contrary, the V , W\nCPD F\nand energy level structure of the control (TPPEt) SbBr films and TPBi-treated (TPPEt) SbBr\n2 5 2 5\nfilms remained almost unchanged due to the lack of π−π stacking interaction between the\n(TPPEt) SbBr and TPBi (Figs. R7d−f).\n2 5\nIn the original manuscript, to verify the enhancement of charge injection by π−π interaction,\nelectrochemical impedance spectroscopy (EIS), capacitance−voltage (C−V), and transient EL\nmeasurements have been conducted on our target (TPPEtCz) Sb Br device and control\n2 2 8\n(TPPEt) SbBr device. We have demonstrated that in EIS, (TPPEtCz) Sb Br -based devices\n2 5 2 2 8\nwith π−π stacking interaction exhibit a reduction of R from 34 to 29 Ω, which is beneficial to\ns\n12\nthe charge injection and transport. Moreover, R was greatly decreased from 47 to 1.4 kΩ,\nrec\nwhich facilitates the electron-hole recombination within devices. In the C−V curves, the slope\nof (TPPEtCz) Sb Br -based devices in the recombination region is steeper than that of the\n2 2 8\ncontrol devices, signifying an increased injection of unbalanced electrons that support a rapid\nradiative recombination rate. In the transient EL spectra, (TPPEtCz) Sb Br -based devices\n2 2 8\nshow a steeper upward trend at the beginning compared to the case of control devices, which\nmanifests a rapid establishment of steady-state EL. When the pulse voltage was deactivated, a\nfast EL decay was detected for (TPPEtCz) Sb Br -based devices, which is attributed to the\n2 2 8\nfewer cumulative carriers caused by balanced injection and rapid recombination of carriers\nthrough interfacial π−π interaction.\nFigure R7. a,b, KPFM images (a) and UPS spectra (b) of (TPPEtCz) Sb Br and\n2 2 8\nTPBi-treated (TPPEtCz) Sb Br films. c, Energy band of (TPPEtCz) Sb Br -based LEDs. d,e,\n2 2 8 2 2 8\nKPFM images (d) and UPS spectra (e) of (TPPEt) SbBr and TPBi-treated (TPPEt) SbBr\n2 5 2 5\nfilms. f, Energy band of (TPPEt) SbBr -based LEDs.\n2 5\nWe performed additional semiconductor device simulations to theoretically analyze the\ncharge carrier distribution, transport, and recombination of LEDs with and without interfacial\nπ−π interaction (Nat. Photonics 18, 425, 2024). According to the device configuration and\n13\nenergy level distribution of two devices and the carrier mobility of two Sb halide films, the\ncharge carrier transport characteristics within device were calculated. Figs. R8a,b show the\ncharge carrier concentration distribution curves of two devices, where the hole and electron\nconcentrations were extracted to as 1.08×108 cm−3 and 2.60×1022 cm−3 for\n(TPPEt) SbBr -based devices, and 2.48×1011 cm−3 and 3.62×1023 cm−3 for\n2 5\n(TPPEtCz) Sb Br -based devices, respectively. Consequently, the (TPPEtCz) Sb Br -based\n2 2 8 2 2 8\nLEDs with interfacial π−π interaction reach a more efficient and balanced charge transport\nbehavior, as described in the two-dimensional carrier distribution visualization mapping (Fig.\nR8c). Figs. R8d,e show the simulated energy band distribution of two devices in equilibrium\nstate. We found that the devices with interfacial π−π interaction exhibit a lower energy\nbarrier (φ = 0.96 eV; φ = 0.51 eV) compared with the control ones (φ = 1.23 eV;\nh e h\nφ = 0.79 eV). We also calculated the exciton concentration of two devices based on the\ne\ndistribution position of holes, excitons and recombination rates inside the devices (Fig. R8f).\nThe exciton concentration of (TPPEtCz) Sb Br -based devices with interfacial π−π\n2 2 8\ninteraction (2.59 × 1015 cm−3) is nearly 13 times higher than that of the (TPPEt) SbBr -based\n2 5\ncounterpart (1.87 × 1014 cm−3). As a result, the (TPPEtCz) Sb Br -based LEDs deliver\n2 2 8\nsignificantly higher exciton recombination rate (8.29 × 1022 cm−3 s−1) compared to control\n(TPPEt) SbBr -based devices (7.62 × 1022 cm−3 s−1). These changes improve the charge\n2 5\ncarrier transport and exciton radiative recombination in the device, promoting the\nelectro-optical energy conversion, resulting in enhanced electroluminescence performance of\n(TPPEtCz) Sb Br -based LEDs through interfacial π−π interaction.\n2 2 8\n14\na\nElectron injection\nPEDOT:PSS Sb halide TPBi\n1×1023\nFigure R8. a,b, Charge carrier concentration distribution of LEDs based on (TPPEt) SbBr\n2 5\n(a) and (TPPEtCz) Sb Br (b) films. c, Carrier distribution mapping of two LEDs. d,e,\n2 2 8\nEnergy band distribution of (TPPEt) SbBr -based device (d) and (TPPEtCz) Sb Br -based\n2 5 2 2 8\ndevice (e) in equilibrium state. Gray line and red line are the conduction band minimum and\nvalence band maximum of different functional layers, respectively. φ and φ are the hole\nh e\ninjection barriers and electron injection barriers, respectively. f, Exciton density (left) and\nexciton recombination rate distribution (right) of two LEDs.\nRevisions: The following sentences have been added in the Revised Manuscriptto elaborate\non the influence of π−π interaction on charge transport.\nOn Page 16, line 265–286: “As mentioned earlier, the presence of planar π–conjugated\naromatic rings in both (TPPEtCz) Sb Br and TPBi creates favorable conditions for\n2 2 8\nintermolecular π–π stacking, providing an effective pathway for improved charge transport.\nWe performed kelvin probe force microscopy (KPFM) and ultraviolet photoelectron\nspectroscopy (UPS) measurements42,43 to characterize the charge transport properties of two\nsamples. A thin layer of TPBi (2 nm) was deposited on (TPPEtCz) Sb Br to probe their\n2 2 8\ninterfacial interaction. As shown in Fig. 3a, the average contact potential difference (V ) of\nCPD\nthe pure (TPPEtCz) Sb Br films was 302.6 mV, which increased significantly to 330.4 mV for\n2 2 8\nTPBi-treated (TPPEtCz) Sb Br films, indicating a reduction in the work function (W ) after\n2 2 8 F\nTPBi treatment that promotes more efficient electron injection from TPBi into the emitter\nlayer. According to the cutoff region of the UPS spectra, the W of TPBi-treated\nF\n(TPPEtCz) Sb Br and (TPPEtCz) Sb Br films is estimated to be 4.83 and 4.88 eV,\n2 2 8 2 2 8\nrespectively (Supplementary Fig. 25b). The reduction of the W caused by\nF\nTPBi/(TPPEtCz) Sb Br -induced π−π stacking interaction favors the electron transport of\n2 2 8\n15\n) e N(\ngol\n)hN(\ngol\n1×1023\n(TPPEt)2SbBr5\n(TPPEtCz)2Sb2Br8\n1\n(TPPEt)2SbBr5\n(TPPEtCz)2Sb2Br8\n30\n20\n10\n0\n35 40 45\nytisned\nnoticxE\n)3-mc\n4101×(\n8.6 PEDOT:PSS Sb halide\n8.4 2.59 × 1015 8.2\n8.0\n7.8 7.6\n2\n1.87 × 1014\n0\n35 40 45\netar\nnoitanibmoceR\n)1-s\n3-mc 2201×(\n(TPPEt)2SbBr5 (TPPEtCz)2Sb2Br8\n2 8.29 × 1022 1\n0 -1 7.62 × 1022\n-2\n-3\n-4\n-20 0 20 40 60 80 100 120\nRelative position (nm)\n)Ve(\nygrenE\nTPBi\nITO PEDOT:PSS Sb halide\nRelative position (nm)\nlA/FiL\n(TPPEtCz)2Sb2Br8\n2 1 φe = 0.51 eV\n-2 φh = 0.96 eV\n-3 EV\n-4\n-20 0 20 40 60 80 100 120\n)Ve(\nygrenE\nTPBi\nITO PEDOT:PSS Sb halide\nRelative position (nm)\nlA/FiL\nb c\n1019\n1016\n1013\n1010\n107 104\n0 20 40 60 80 100 120\nd e f\n(TPPEt)2SbBr5\nEc\nφe = 0.79 eV\nEf\nφh = 1.23 eV\nEV\n)3-mc(\nytisned\negrahC\n(TPPEt)2SbBr5\nRelative position (nm)\nlA/FiL PEDOT:PSS Sb halide TPBi OTI\n2.60 × 1022 1025 1022\n1019\n1016\n1013\n1.08 × 108\n1010\n107 104\n0 20 40 60 80 100 120\n)3-mc(\nytisned\negrahC\n(TPPEtCz)2Sb2Br8\n3.62 × 1023 E H l o e l c e t r d o e n n d si e ty nsity\n2.48 × 1011\nRelative position (nm)\nlA/FiL PEDOT:PSS Sb halide TPBi OTI\nemitter layer, which is consistent with previous reports38,41. In addition, the VBM of\n(TPPEtCz) Sb Br films is increased from −5.82 eV to −5.66 eV, and the corresponding CBM\n2 2 8\nis increased from –3.26 eV to −3.10 eV. The overall upward shift of the energy level of the\nemitter layer improves band alignment with the transport layers, thus reducing the injection\nbarrier and minimizing charge accumulation at the interface, which is conducive to the faster\ninjection of both hole and electron (Supplementary Fig. 25c). On the contrary, the V , W\nCPD F\nand energy level structure of the control (TPPEt) SbBr films and TPBi-treated\n2 5\n(TPPEt) SbBr films remained almost unchanged (Supplementary Fig. 26) due to the lack of\n2 5\nπ−π stacking interaction between the (TPPEt) SbBr and TPBi.”\n2 5\nOn Page 17–18, line 304–318: “We performed semiconductor device simulations43 to\ntheoretically analyze the charge carrier distribution, transport, and recombination of two\ndevices. Supplementary Figs. 28a,b show the charge carrier concentration distribution\ncurves of two devices, where the hole and electron concentrations were extracted to as 1.08\n× 108 cm−3 and 2.60 × 1022 cm−3 for (TPPEt) SbBr -based devices, and 2.48 × 1011 cm−3\n2 5\nand 3.62 × 1023 cm−3 for (TPPEtCz) Sb Br -based devices, respectively, presenting a more\n2 2 8\nefficient and balanced charge transport (Supplementary Fig. 28c) for (TPPEtCz) Sb Br\n2 2 8\nsystem with π−π interactions. Supplementary Figs. 28d,e display the simulated energy band\ndistribution of two devices in equilibrium state, where the energy barrier of the\n(TPPEtCz) Sb Br -based devices (φ = 0.96 eV; φ = 0.51 eV) was lower than that of the\n2 2 8 h e\ncontrol ones (φ = 1.23 eV; φ = 0.79 eV). In addition, the calculated exciton concentration\nh e\nand exciton recombination rate of (TPPEtCz) Sb Br -based devices were both higher than\n2 2 8\nthose of the control (TPPEt) SbBr -based devices (Supplementary Fig. 28f). These changes\n2 5\nimprove the charge carrier transport and exciton radiative recombination in the device with\ninterfacial π−π interaction, promoting the electro-optical energy conversion, resulting in\nenhanced electroluminescence performance of (TPPEtCz) Sb Br -based LEDs.”\n2 2 8\nSupplementary Figs. 25, 26, 28 were added in the Supporting Information.\n4) Performance comparison of devices with and without π−π interaction\nWe fabricated (TPPEtCz) Sb Br -based devices with ZnO electron transport layer\n2 2 8\n(ITO/PEDOT:PSS/(TPPEtCz) Sb Br /ZnO/LiF/Al) and measured their electroluminescence\n2 2 8\nperformance. As shown in Figs. R9, the device exhibits an EQE of 5.4%, similar to the\nreferences (5.12%) mentioned by the reviewer, but significantly lower than that of our target\ndevices (19.4%) withinterfacial π−π interaction. These results demonstrate that our proposed\ninterfacial structure with π−π interaction effectively enhances the performance of LEDs,\nwhich is attributed to the improvement of charge carrier transport, facilitating moreefficient\nradiative recombination.\n16\n102\n101\n100\n10-1\n10-2\n10-3\n0 3 6 9 12\nVoltage (V)\nFigure R9. a, J−V−L and EQE−J of (TPPEtCz) Sb Br -based devices with ZnO electron\n2 2 8\ntransport layer (ITO/PEDOT:PSS/(TPPEtCz) Sb Br /ZnO/LiF/Al). b, J−V−L and EQE−J of\n2 2 8\n(TPPEtCz) Sb Br -based devices with TPBi electron transport layer\n2 2 8\n(ITO/PEDOT:PSS/(TPPEtCz) Sb Br /TPBi/LiF/Al).\n2 2 8\nA brief summary: based on the detailed discussions above, we have clearly elucidated the\norigin of the discrepant device performance between our (TPPEtCz) Sb Br and the\n2 2 8\npreviously reported TPPcarzSbBr system. We have identified a previously unreported\n4\nnon-covalent π−π stacking interaction at the (TPPEtCz) Sb Br /TPBi interface that\n2 2 8\nfundamentally modifies the interfacial contact. This interaction significantly facilitates charge\ntransfer and injection, enabling efficient exciton recombination under electrical field. The\nexistence and role of this interfacial π−π interaction between Sb halides and TPBi, which\nhave not been reported in previous studies, were reasonably confirmed through a combination\nof detailed experimental characterizations and theoretical calculations. Consequently, the\ndeliberate design of this specific interfacial interaction represents a decisive step in\ntranslating the high PLQY of Sb-halide emitters into superior EQE of device, constituting the\nkey novelty of our work.\n17\n)2-mc\nAm(\nytisned\ntnerruC\n104\n102\n100\n)2-m\ndc(\necnanimuL\n102\n100\n10-2\n10-2 10-1 100 101 102\n)%\n(EQE\n101\n100\n10-1\n10-2\n100 101 102\nEQEmax = 19.4%\nCurrent density (mA cm-2)\n)%\n(EQE\n102\n101\n100\n10-1\n10-2\n0 3 6 9 12\nVoltage (V) Current density (mA cm-2)\n)2-mc\nAm(\nytisned\ntnerruC\n104\n102\n100\n)2-m\ndc(\necnanimuL\na\nITO/PEDOT:PSS/(TPPEtCz)SbBr/ZnO/LiF/Al\n2 2 8\nEQEmax = 5.4%\nb ITO/PEDOT:PSS/(TPPEtCz)SbBr/TPBi/LiF/Al\n2 2 8\nReviewer #2 (Remarks to the Author):\nIn this manuscript, the authors present a comprehensive study on antimony halide hybrid\nsystems with carbazole-functionalized organic cations. Their work demonstrates the critical\nrole of carbazole-based TPPEtCz+ organic cations in facilitating high-quality film formation,\nsuppressing non-radiative recombination, and enhancing electrical conductivity. Furthermore,\nthe fabricated antimony halide-based LED devices achieve a record-high external quantum\nefficiency and an extended half-lifetime, representing a significant advancement in the metal\nhalide LED field. While the manuscript is well-structured and merits publication in Nature\nCommunications, some conclusions require additional clarification and experimental\nevidence.\nResponse: We thank the reviewer very much for the positive comments, and for\nrecommending publication of our paper in Nature Communications. We have responded to\ndetailed comments as follows and revised the manuscript accordingly.\nQ1. The authors attribute the slowed crystallization rate of (TPPEtCz) Sb Br films to\n2 2 8\nTPPEtCz+ cations. However, the underlying mechanism remains unclear. Could the authors\nprovide further discussion or experimental evidence to elucidate how these organic cations\nmodulate crystallization kinetics?\nResponse: Thanks for this valuable comment, which has encouraged us to think more deeply.\nAccording to your constructive advices, we provided detailed discussions and experimental\nevidences to clarify how organic cations modulate the crystallization kinetics.\n1) We performed comprehensive in-situ PL and in-situ UV-vis absorption measurements to\nelucidate how TPPEtCz+ and TPPEt+ organic cations modulate the crystallization kinetics\nduring spin-coating and annealing processes. As shown in Fig. R10a, for the control\n(TPPEt) SbBr films, the PL intensity peaked at ~420 nm of TPPEt+ cations gradually\n2 5\ndecrease from the beginning of the spin-coating process, and the PL signal peaked at 680 nm\nfrom (TPPEt) SbBr appears at about 3.86 s, which corresponds to the nucleation stage of\n2 5\n[SbBr ]2− clusters (Phase I). Following closely behind is a rapid increase of PL intensity,\n5\nindicating that after the crystal nucleus concentration reaches a critical value, the nuclei\n18\nundergo explosive growth, corresponding to the crystal nuclei growth stage (Phase II, 0.53 s).\nFinally, the PL intensity shows a slow upward trend until the end of spin-coating, reflecting\nan enhanced crystallization via the Ostwald ripening process (Phase III, 0.67 s). In contrast,\nthe utilization of the TPPEtCz+ cation notably delayed all three stages, including nucleation\n(Phase I, 4.23 s), crystal growth (Phase II, 1.82 s), and Ostwald ripening process (Phase III,\n2.63 s), in the (TPPEtCz) Sb Br films. This delayed crystallization process can also be\n2 2 8\nvalidated by the in-situ UV-vis absorption spectra in Fig. R11. During the annealing process,\nthe in-situ PL intensities of two films decreased slightly over timewithout any peak shift\n(Figs. R10c,d), indicating that crystal nucleation and growth were essentially completed\nduring the spin-coating phase, which is attributed to the rapid solvent evaporation of\ndichloromethaneused in our experiment with a low boiling point.\n1.0\n0.5\n0.0\n1.0\n0.5\n0.0\n0 1 2 3 4 5 6 7 8 9 56 57 58 59 60\nFigure R10. a,b, In-situ PL spectra (a) and PL intensity evolution (b) of two films during the\nspin-coating process. c,d, In-situ PL spectra (c) and PL intensity evolution (d) of two films\nduring the annealing process.\n19\n).u.a(\nytisnetnI\n800\n600\n400\n800\n600\n400\n0 1 2 3 4 5 6 7 8 9 56 57 58 59 60\nTime (s)\nTime (s)\n)mn(\nhtgnelevaW\n800\n600\n400\n)mn(\nhtgnelevaW\n800\n600\n400\n0 100 200 300 400 500 600\nTime (s)\n1.00\n0.75\n1.00\n0.75\n0 100 200 300 400 500 600\n).u.a(\nytisnetnI\na c\nSpin-coating Annealing\nPhase Ⅱ Phase Ⅱ (Δt2 = 0.53 s)\n(Δt1 = 3.86 s) PL@(TPPEt)2SbBr5\nPL@TPPEt Phase Ⅱ (Δt3= 0.67 s)\nPhase Ⅱ Phase Ⅱ (Δt2 = 1.82 s)\n(Δt1 = 4.23 s) PL@(TPPEtCz)2Sb2Br8\nPL@TPPEtCz Phase Ⅱ (Δt3= 2.63 s)\nb d\nPhase Ⅱ\nPhase Ⅱ (k2 = 0.096 s−1)\nPhase Ⅱ (k1 = 0.246 s−1)\nPhase Ⅱ Phase Ⅱ (k2 = 0.018 s−1)\nPhase Ⅱ (k1 = 0.187 s−1)\nTime (s)\n500\n400\n500\n400\n0 100 200 300 400 500 600\nFigure R11. a,b, In-situ UV-vis absorption spectra (a) and peak position evolution (b) of two\nfilms during the spin-coating process. c,d, In-situ UV-vis absorption spectra (c) and peak\nposition evolution (d) of two films during the annealing process.\n2) We employed the Avrami model to investigate the crystallization rate of (TPPEt) SbBr\n2 5\nand (TPPEtCz) Sb Br films based on the PL intensity evolution during the spin-coating\n2 2 8\nprocess. The model is defined as kt = (−ln(1−α))1/n, where k is the effective reaction rate\nconstant (crystallization rate constant herein), n is the Avrami exponent, t is time, and α is the\nconversion fraction characterized by the PL intensity of the films (Angew. Chem. Int. Ed. 63,\ne202411361, 2024). From the PL intensity-time curves (Fig. R10b), two rate constants k and\n1\nk can be fitted, which k corresponds to the growth ofcrystal nucleus, while k represents the\n2 1 2\nOstwald ripening process. In comparison, the k (0.187 s−1) and k (0.018 s−1) values of the\n1 2\n(TPPEtCz) Sb Br are smaller than those of the control (TPPEt) SbBr (k = 0.246 s−1, k =\n2 2 8 2 5 1 2\n0.096 s−1). These specifically results show that TPPEtCz+ cations effectively retards the\ncrystallization rate of crystal, yielding compact films with reduced trap density and superior\nluminescent properties.\n3) We further used NMR spectroscopy to probe the interactions between inorganic and\norganic components in the precursor solutionto investigate the reasons for the modulation of\ncrystallization kinetics by organic cations. As shown in Fig. R12a, the 1H NMR signals of\npure TPPEtBr exhibit a downfield shift compared to (TPPEt) SbBr , indicating a hydrogen\n2 5\n20\n)mn(\nhtgnelevaW\n500\n400\n500\n400\n0 100 200 300 400 500 600\nTime (s)\nTime (s)\n)mn(\nhtgnelevaW\n500\n400\n500\n400\n0 1 2 3 4 5 6 7 8 9 56 57 58 59 60\n)mn(\nhtgnelevaW\n500\n400\n500\n400\n0 1 2 3 4 5 6 7 8 9 56 57 58 59 60\nTime (s)\nTime (s)\n)mn(\nhtgnelevaW\na c\nSSppiinn--ccooaattiinngg Annealing\nPhase Ⅱ\nPhase Ⅱ Abs@(TPPEt)2SbBr5\nPhase Ⅱ\nPhase Ⅱ\nPhase Ⅱ Abs@(TPPEtCz)2Sb2Br8\nPhase Ⅱ\nb d\nPhase Ⅱ Phase Ⅱ\nPhase Ⅱ\nPhase Ⅱ Phase Ⅱ\nPhase Ⅱ\nbond interaction between TPPEt+ and [SbBr ]2− clusters. Importantly, the 1H NMR peaks of\n5\npure TPPEtCzBr in (TPPEtCz) Sb Br also experience a downfield shift, but with a\n2 2 8\nsignificantly larger magnitude than that of the (TPPEt) SbBr (Fig. R12b), indicating that\n2 5\nTPPEtCz+ has a stronger hydrogen bond interaction with [Sb Br ]2−. This stronger\n2 8\nhydrogen-bonding interaction slows down the crystal growth, enabling the acquisition of\nhigh-quality (TPPEtCz) Sb Br films with few defects (Nat. Photonics 17, 755, 2023). To\n2 2 8\nsemi-quantitatively analyze the weak intermolecular interactions between the inorganic and\norganic components, the 2D Hirshfeld surfaces and fingerprint plots of two Sb halide\nstructures are illustrated in Fig. R13, which are generated using CrystalExplorer software.\nThese analyses show that H···Br hydrogen bonds and H···Sb interactions account for 91.5%\nand 3.9% of the total intermolecular interactions in (TPPEtCz) Sb Br , respectively,\n2 2 8\nmarkedly higher than those in the control (TPPEt) SbBr (H···Br = 85.4%, H···Sb = 2%).\n2 5\nThis confirms that the hydrogen-bonding interactions play a non-negligible role in the\ncrystallization kinetics of (TPPEtCz) Sb Br , consistent with the experimental observations.\n2 2 8\nTPPEtBr\n8.5 8.0 7.5 7.0 6.5\n21\n).u.a(\nytisnetnI\nH1-3\n(TPPEt)SbBr\n2 5\nH1-3\nChemical shift (ppm)\nTPPEtCzBr\nH4-6\nH7,12\nH8-11\nH13\nH4-6\nH8-11 H7,12 H13\n8.5 8.0 7.5 7.0 6.5\n).u.a(\nytisnetnI\na\nTPPEtBr\n[SbBr\n5\n]2−\n(TPPEt)SbBr\n2 5\nb\nTPPEtCzBr\n(TPPEtCz)SbBr\n2 2 8\n[Sb 2 Br 8 ]2−\nChemical shift (ppm)\n(TPPEtCz)SbBr\n2 2 8\nFigure R12. a, 1H NMR spectra of TPPEtBr and (TPPEt) SbBr . b, 1H NMR spectra of\n2 5\nTPPEtCzBr and (TPPEtCz) Sb Br .The right part is marked as the detected 1H peaks in the\n2 2 8\nmolecular structure of TPPEtBr, (TPPEt) SbBr , TPPEtCzBr, and (TPPEtCz) Sb Br .\n2 5 2 2 8\nFigure R13. a,b, Hirshfeld surfaces and 2D fingerprint plots of (TPPEt) SbBr (a) and\n2 5\n(TPPEtCz) Sb Br (b). Red, white, and blue regions of the Hirshfeld surfaces show positive\n2 2 8\n(close contact), neutral, and negative energies, respectively.\n4) Based on the above analysis, the distinct crystallization pathways of the (TPPEt) SbBr\n2 5\nand (TPPEtCz) Sb Br films are illustrated in Fig. R14. TPPEtCz+, with larger steric\n2 2 8\nhindrance, forms stronger hydrogen bonds with [Sb Br ]2− species compared to the control\n2 8\nTPPEt+ system, resulting in a slower and more complete crystal restructuring, thus enhancing\nthe quality of the prepared (TPPEtCz) Sb Br films.\n2 2 8\n22\n∆t1 = 3.86 s\n∆t2 = 0.53 s\n∆t3 = 0.67 s\nTPPEt+\nTPPEtCz+\nPrecursor Nucleation Growth Ripening\n[SbBr]2-\n5\n∆t1 = 4.23 s\n[SbBr]2-\n∆t2 = 1.82 s 2 8\n∆t3 = 2.63 s (TPPEt)SbBr\n2 5\n(TPPEtCz)SbBr\n2 2 8\nPrecursor Nucleation Growth Ripening\nFigure R14. Schematic crystallization pathways of (TPPEt) SbBr and (TPPEtCz) Sb Br\n2 5 2 2 8\nfilms.\nRevisions: The following sentences have been modified in the Revised Manuscript to\nelaborate on the crystallization kinetics in detail.\nOn Page 12–13, line 191–218: “The initial PL peak position (< 420 nm) is correlated with\norganic cations. As shown in Fig. 2h, for the (TPPEt) SbBr , the PL intensity of TPPEt+\n2 5\ncations gradually decrease from the beginning of the spin-coating process, and the PL signal\npeaked at 680 nm from (TPPEt) SbBr appears at about 3.86 s, which corresponds to the\n2 5\nnucleation stage of [SbBr ]2− clusters (Phase I). Following closely behind is a rapid increase\n5\nof PL intensity, indicating that after the crystal nucleus concentration reaches a critical value,\nthe nuclei undergo explosive growth, corresponding to the crystal nuclei growth stage (Phase\nII, 0.53 s). Finally, the PL intensity shows a slow upward trend until the end of spin-coating,\nreflecting an enhanced crystallization via the Ostwald ripening process (Phase III, 0.67 s). In\ncontrast, the utilization of the TPPEtCz+ cation notably delayed all three stages in the\n(TPPEtCz) Sb Br films, including nucleation (Phase I, 4.23 s), crystal growth (Phase II,\n2 2 8\n1.82 s), and Ostwald ripening process (Phase III, 2.63 s). This delayed crystallization process\ncan also be validated by the in-situ UV-vis absorption spectra in Supplementary Fig. 16.\nDuring the annealing process, the in-situ PL intensities of two films decreased slightly over\ntime without any peak shift (Supplementary Fig. 17), indicating that crystal nucleation and\ngrowth were essentially completed during the spin-coating phase, which is attributed to the\nrapid solvent evaporation of dichloromethane used in our experiment with a low boiling point.\nWe employed the Avrami model to investigate the crystallization rate of (TPPEt) SbBr and\n2 5\n(TPPEtCz) Sb Br films based on the PL intensity evolution during the spin-coating process.\n2 2 8\nThe model is defined as kt = (−ln(1−α))1/n, where k is the effective reaction rate constant\n(crystallization rate constant herein), n is the Avrami exponent, t is time, and α is the\nconversion fraction characterized by the PL intensity of the films34. From the PL\nintensity-time curves (Fig. 2i), two rate constants k and k can be fitted, in which k\n1 2 1\ncorresponds to the growth of crystal nucleus, while k represents the Ostwald ripening\n2\nprocess. In comparison, k (0.187 s−1) and k (0.018 s−1) values of the (TPPEtCz) Sb Br are\n1 2 2 2 8\nsmaller than those of the control (TPPEt) SbBr (k = 0.246 s−1, k = 0.096 s−1). These\n2 5 1 2\nspecifically results show that TPPEtCz+ cations effectively retards the crystallization rate of\n23\ncrystal, yielding compact films with reduced trap density and superior luminescent\nproperties35,36.”\nPage 9: Figs. 2h,i were replaced by new figure.\nSupplementary Figs. 16, 17, 20, 21, 24 were added in the Supporting Information.\nQ2. A red shift is observed in the electroluminescence spectra (Supplementary Fig. 5)\ncompared to the photoluminescence spectra (Fig. 2e). What causes this discrepancy?\nResponse: Thanks for your useful comment. As mentioned by the reviewer, the\nelectroluminescence spectra of device with a peak at 653 nm has a redshift of approximately\n4 nm compared to the photoluminescence spectra of (TPPEtCz) Sb Br films.\n2 2 8\nThe redshift\nprobably results from the Stark effect induced by electric field, as already demonstrated in\nseveral organic and perovskite systems (Nat. Commun. 14, 2394, 2023; Nat. Commun. 12,\n1246, 2021). The essence of the Stark effect is the modulation of the energy level structure of\nluminescent materials by an external electric field, which reduces the radiative transition\nenergy of charge carriers, ultimately resulting in a shift of spectral peak positions towards\nlonger wavelengths (Nat. Photonics, 7, 407, 2013).\nRevisions: The following sentence has been added in the Revised Manuscript.\nOn Page 8, line 123–125: “A slight redshift was detected in the EL spectra compared to the\nPL spectra, which might be caused by the Stark effect resulting from the electric field10.”\nQ3. The turn-on voltage (more than 6 V) for large-area devices based on (TPPEtCz) Sb Br\n2 2 8\nappears relatively high (Supplementary Fig. 19a). This phenomenon is also observed in the\nother carbazole-derived LEDs. What underlying factors contribute to these high turn-on\nvoltages in the large-area devices and carbazole-derived systems?\nResponse: We sincerely appreciate the reviewer’s valuable comments regarding the relatively\nhigh turn-on voltage observed in our large-area devices and other carbazole-derived devices.\nWe carefully re-examined the fabrication process of each functional layer and identified that\nthe thickness of the emitter layer in large-area devices (61 nm) and carbazole-derived devices\n(TPPMeCz-based, 55 nm; TPPPhCz-based, 58 nm; TPPNaCz-based, 62 nm) is thicker than\nthat in champion devices (43 nm), as shown in Fig. R15, which is a reasonable and critical\nreason for the elevated turn-on voltage. This increased thickness directly leads to a higher\n24\nseries resistance and, consequently, a higher applied turn-on voltage is needed to achieve the\nsame electric field required for charge injection and exciton formation (Adv. Funct. Mater. 29,\n1902008, 2019). To address this, we systematically reduced the concentration of the\nprecursor to obtain thinner emitter layers. Specifically, the precursor concentration for\nlarge-area devices was decreased from 0.01 mmol mL−1 to 0.008 mmol mL−1, and that for\ncarbazole-based devices was reduced from 0.01 mmol mL−1 to 0.007 mmol mL−1. These\nadjustments successfully lowered the turn-on voltages to 4.24 V and 4.2 V for large-area\ndevices and carbazole-derived devices (Figs. R16,17), respectively, making them comparable\nto that of the champion device (4.2 V).\nFigure R15. a−e, AFM sections of Sb halide emitters based on champion device (a),\nlarge-area device (b), TPPMeCz-based device (c), TPPPhCz-based device (d), and\nTPPNaCz-based device (e). The scale bar is 4 µm.\n2 2 8\ndevices.\nFigure R17. a,b, J−V−L (a) and EQE−J curves (b) of devices based on extended\ncarbazole-functionalized Sb halide films.\nRevisions: Figs. 4e, f were replaced by new figures.\nSupplementary Figs. 33c−e were replaced by new figures in the Supporting Information.\nQ4. The authors state that “For the (TPPEt) SbBr , the calculated projected density of states\n2 5\n(pDOS) show that the top of bandgap consists mainly of the valence band maximum (VBM)\nof Sb 5s and Br 4p orbitals, while the bottom of bandgap is composed of the lowest\nunoccupied molecular orbital (LUMO) of TPPEt+ (Fig. 2a and Supplementary Fig. 7a).”\nHowever, it should be noted that both the VBM and LUMO are calculated for the properties\nof the entire (TPPEt) SbBr system and cannot be meaningfully assigned to individual\n2 5\nfragments such as TPPEt+ or [SbBr ]2−. Therefore, the statement of “the lowest unoccupied\n5\nmolecular orbital (LUMO) of TPPEt+” and HOMO, LUMO, VBM, CBM labeled in Fig.2a-d\nare very confusing. The authors need to clarify this statement and ensure that the type I or\n26\ntype II semiconductor of these hybrids are consistent with the definition in the heterostructure\nsemiconductors.\nResponse: We apologize for any confusion that may have arisen due to the potential lack of\nclarity in our language expressions and figures regarding this part of the content. We have\nmodified the relevant discussions and corrected the figures in the Revised Manuscriptfor a\nbetter understanding. Specifically, for the (TPPEt) SbBr , the valence band maximum (VBM)\n2 5\nis constructed mainly by the hybridization of Sb 5s and Br 4p orbitals, while the conduction\nband minimum (CBM) is composed mainly of TPPEt+ cations (Fig. R18a). In contrast, both\nVBM and CBM of (TPPEtCz) Sb Br are mainly composed of Sb and Br\n2 2 8\norbitals.\nFigure R18. a-d, pDOS diagrams of (TPPEt) SbBr (a) and (TPPEtCz) Sb Br (c) with\n2 5 2 2 8\nemphasizing the charge density plots for VBM and CBM, respectively; illustration of the\nenergy level alignments of (TPPEt) SbBr (b) and (TPPEtCz) Sb Br (d), including the\n2 5 2 2 8\nevolution of exciton formation, transfer, and radiative recombination processes.\nRevisions: The following sentences have been modified in the Revised Manuscript to\nenhance the understanding of heterostructures.\nOn Page 10, line 149–158: “the valence band maximum (VBM) is constructed mainly by the\nhybridization of Sb 5s and Br 4p orbitals, while the conduction band minimum (CBM) is\ncomposed mainly of TPPEt+ cations (Fig. 2a and Supplementary Fig. 8a). As a result, the\nwide-band-gap TPPEt+ cations and the inorganic [SbBr ]2− polyhedrons form a type-II band\n5\nalignment (Fig. 2b). In this case, the excited electrons in the [SbBr ]2− polyhedrons will be\n5\ntransferred to the energy level of the organic TPPEt+ cation, leading to the excitons to\ndissipate through non-radiative recombination pathways due to the thermal vibrations26. In\ncontrast, both VBM and CBM of (TPPEtCz) Sb Br are mainly composed of Sb and Br\n2 2 8\norbitals, while the large organic TPPEtCz+ plays a separator to isolate the inorganic\n[Sb Br ]2− parts (Fig. 2c and Supplementary Fig. 8b).”\n2 8\nPage 9: Figs. 2a–d were replaced by new figure.\nIn this study, Zhuangzhuang Ma et al. present a report on promising solution processed\nzero-dimensional hybrid antimony (Sb) based emitters for highly-efficient LEDs,\ndemonstrating a promising approach towards lead-free high-performance optoelectronic\ndevices. This study represents a significant and important breakthrough in the field of\nzero-dimensional organic-inorganic hybrid LED systems and is therefore highly relevant and\ninteresting in this field. However, the reviewer suggests the authors consider the following\npoints for strengthening the manuscript prior to publication in Nature Communications.\nResponse: We appreciate the valuable suggestions given by the reviewer to help us improve\nthe quality of this work. We have responded to detailed comments as follows and revised the\nmanuscript accordingly.\nQ1. As shown in Fig. 1f, there has been a several reports on LEDs employing hybrid metal\nhalide emitters in recent years. In addition to the Cu, Mn, and Sb-based systems presented by\nthe authors, numerous studies on other metal halides (e.g., Sn-based) have also been reported.\nIt is therefore suggested that such examples be included in Fig. 1f of the main text or in a\nsupplementary table.\nResponse: We appreciate the reviewer’s kind reminder. According to your constructive\nadvices, we have supplemented examples of Sn-based perovskite LEDs in Fig. 1f and in\nsupplementary table 3. The specific comparison of device performances based on lead-free\nmetal halide perovskites or perovskites derivatives is shown in Fig. R19 and Table R1 for\nbetter understanding by reviewerhere.\ndetails).\nTable R1. Summary of electroluminescent performances for recently reported lead-free metal\nhalide LEDs.\nEL Peak Max. Lum. T50\nType Materials Ref.\n(nm) EQE (cd m−2) (min)\n(TPPEtCz)2Sb2Br8 653 19.4% 3,669 10,190 This work\n(TPE-TPP)2Sb2Br1.16\n473 1.1% 335 N/A Small20, 2403788 (2024)\nCl6.84\nSb-based (MePPh3)2SbCl5 593 3.1% 3,500 5.1 Angew. Chem. 61, e202113450 (2022)\nCs3Sb2Br9 408 0.206% 29.6 360 ACS Energy Lett.5, 385 (2020)\nTPPcarzSbBr4 653 5.12% 5,957 5.2 Adv. Mater.35, 2209417 (2023)\n(Ph4P)2SbCl5 650 6.47% 6,689 183.3 Angew. Chem. 64, e202513452 (2025)\nTEA2SnI4 630 20.29% 800 1,656 Nature622, 493 (2023)\nFPEA2SnI4 627 15.59% 890 4,296 Laser Photonics Rev.19, e00727 (2025)\nTEA2SnI4 630 10.12% 195 N/A Adv. Funct. Mater.35, 2506504 (2025)\nTEA2SnI4 637 1.37% 418 4.8 Small18, e2200036 (2022)\nSn-based\nPEA2SnI4 625 9.32% 328.2 N/A Angew. Chem. 62, e202312728 (2023)\nPEA2SnI4 632 4.97% 100 1,000 Sci. Adv.6, eabb0253 (2020)\nFACsSnI3 894 8.3% 12 W sr−1 m−2 180 Nat. Photon. 17, 755 (2023)\nCsSnI3 948 2.63% 226 W sr−1 m−2 2,370 Nat. Photon. 18, 170 (2024)\nCs3Cu2I5 445 1.12% 263.2 6,480 Nano Lett.20, 3568 (2020)\nCu4I6(bttmp)2 562 5.02% 2,388 2,130 ACS Energy Lett. 6, 2565 (2021)\n[DArDBFDP]2Cu4I4 500 8% 7,000 N/A Sci. Adv. 5, eaav9857 (2019)\nTEA2Cu2Br4 432 0.11% 85 1,200 Nano Energy91, 106664 (2022)\nCu-based\nPEA4Cu4I4 595 1.21% 215.8 37 Nano Lett.25, 2307 (2025)\nMA2CuCl3 500 0.035% 54 8.33 Adv. Sci.9, 2203596 (2022)\n(DFPD)CuBr2 550 0.005% 1 N/A Angew. Chem. 63, e202411047 (2024)\nCsCu2I3 550 0.17% 47.5 310 ACS Nano14, 4475 (2020)\n(Ph4P)2[MnBr4] 521 9.6% 2,339 N/A Adv. Mater.29, 1605739 (2017)\nDBFDPO-MnBr2 520 10.49% 393 N/A Adv. Optical Mater.7, 1801160 (2019)\n[Me3NPh]2MnBr4 522 4.29% 2,898 3,054 Mater. Chem. Front.6, 3102 (2022)\nMn-based\n[Ph3BzP]2[MnBr4] 517 11.42% 4,289 3,000 Chem. Eng. J.474, 145936 (2023)\n(ABI)4MnBr6 629 9.8% 4,700 330 Adv. Funct. Mater.31, 2100855 (2021)\nS-Mn(Binapo)Br2 600 4.09% 843 N/A Chem. Sci.15, 16698 (2024)\nRevisions: Fig. 1f was replaced by new figure.\nSupplementary Table 1 was replaced by new table in the Supporting Information.\nQ2. In the device operational stability data shown in Fig. 1h, the measurement intervals\nduring operation appear to range from several minutes to several tens of minutes. Such\nintervals may not be sufficient to accurately assess the true operational stability of the devices.\nIn addition, the measurement intervals for the control device and the target device also appear\nto differ. For greater clarity and reliability, the operational stability results should be\npresented with consistent and clearly defined measurement intervals. In addition, the current\ndensities of the control device and the target device at each luminance value (specified in the\nmain text as 100 and 30 cd/m2) are also expected to differ, and these values should be\nclearly presented as well.\nResponse: Thanks for your useful comment. We apologize for the misunderstanding caused\nby our inappropriate data presentation in the Fig. 1h. After carefully rechecking our\nexperimental record, we confirm that the measurement intervals of the operational stability\nfor both the control and target devices were in fact consistent, with each data point recorded\nat 2-minute intervals (Fig. R20a). The raw data for both devices are presented in the Fig.\nR20c. We have corrected the misleading representation in Fig. 1h in the Revised Manuscript\nand sincerely regret any confusion this may have caused.\nIn addition, the operational stability of our devices was measured under a fixed current\ndensity, where the current densities of the target device and the control device are 0.41 mA\ncm−2 (corresponding to the initial luminance of 100 cd m−2) and 4.32 mA cm−2\n(corresponding to the initial luminance of 30 cd m−2), respectively.\n2 5\n(TPPEtCz) Sb Br -based LEDs. b, Raw data of the operational stability measurement of two\n2 2 8\ndevices.\nRevisions: The following sentences have been modified in the Revised Manuscript.\nOn Page 8, line 126–130: “We measured the operational stability of two devices under a fixed\ncurrent density (Fig. 1h and Supplementary Fig. 6). The half-lifetime (T ) of\n50\n(TPPEtCz) Sb Br -based LEDs is 10190 min at an initial luminance of 100 cd m-2\n2 2 8\n(corresponding to the current density of 0.41 mA cm−2), which is significantly better than the\ncontrol device (11 min, at initial luminance of 30 cd m-2 corresponding to the current density\nof 4.32 mA cm−2).”\nPage 5: Fig. 1h was replaced by new figure.\nSupplementary Fig. 6 was added in the Supporting Information.\nQ3. Regarding the storage stability data shown in Supplementary Fig. 6, was this\nmeasurement conducted on large-area LEDs? It would also be beneficial to present the actual\ndevice parameters alongside the relative luminance values: for example, the measurement\nvoltage, the corresponding luminance, EQE, and other parameters.\nlarge-area LEDs. According to your constructive advices, we supplemented the evolution of\nactual device parameters over time, including luminance, EQE, and voltage. As shown in Fig.\nR21, after a 30-day storage in air ambient (25 °C; 40−60% humidity), the initial\nelectroluminescence performance of (TPPEtCz) Sb Br -based LEDs measured at a fixed\n2 2 8\ncurrent density of 0.43 mA cm−2 can be almost retained, showing a good storage stability.\nFigure R21. a,b, Evolution of relative luminance (a) and actual device parameters (b) over\ntime, including applied voltage, luminance, EQE, and EL peak of the LEDs based on\n(TPPEtCz) Sb Br films stored in the air ambient (25 °C; 40−60% humidity).\n2 2 8\nQ4. From the PL spectra of each film, the FWHM of the target sample appears to be broader\nthan that of the control sample. Could the authors provide a possible explanation for this\nobservation? In addition, the target sample seems to exhibit a larger Stokes shift. It would be\nhelpful if the authors could provide an explanation for these observations.\nResponse: We appreciate the useful suggestions given by the reviewer. We have carefully\ncompared the FWHM and Stokes shift between the control (TPPEt) SbBr and target\n2 5\n(TPPEtCz) Sb Br samples. Actually, the target sample exhibits a narrower FWHM and a\n2 2 8\nsmaller Stokes shift than the control sample, as shown in Fig. R22. Following the reviewer’s\nsuggestion, we provide a detailed physical explanation for these observations below.\n400 600 800\nFigure R22. a,b, Comparison of FWHM between (TPPEtCz) Sb Br (a) and (TPPEt) SbBr\n2 2 8 2 5\n(b). c,d, Comparison of Stokes shift between (TPPEtCz) Sb Br (c) and (TPPEt) SbBr (d).\n2 2 8 2 5\nIt is widely recognized that in self-trapped excitons (STEs) systems, electron–phonon\ncoupling has a strong connection with the FWHM of STEs luminescence. From the\nperspective of photophysics, the Huang–Rhys factor S is associated with the displacement of\n33\n).u.a(\n.sbA\nWavelength (nm)\n).u.a(\nytisnetni\nLP\n1200\n1000\n800\n600\n400\n200\n0\n400 500 600 700 800 900 1000\n(TPPEtCz)SbBr 2 2 8\n286 nm\n).u.a(\nytisnetnI\nLP\n(TPPEtCz)2Sb2Br8\nFWHM=148.03662 nm\n600\n500\n400\n300\n200\n100\n0\n400 500 600 700 800 900 1000\nWavelength (nm)\n).u.a(\nytisnetnI\nLP\n(TPPEt)2SbBr5\nFWHM=157.44312 nm\nWavelength (nm)\n400 600 800\n).u.a(\n.sbA\nWavelength (nm)\n).u.a(\nytisnetni\nLP\na\nb\nc\nd (TPPEt)SbBr 2 5\n317 nm\nthe equilibrium positions of the nuclei upon exciting the chromophore, which reflects the\nstrength of the electron–phonon coupling (Angew. Chem. Int. Ed. 61, e202113450, 2021). We\ntherefore performed the temperature-dependent PL measurements (Fig. R23a) to evaluate\nHuang–Rhys factor and phonon frequency (ℏω )to reveal the electron−phonon coupling\nphonon\nusing the following equation:\nh\nFWHM(T)  2.36 Sh coth phonon (1)\nphonon 2k T\nB\nwhere ℏ is reduced Planck constant, ω is phonon frequency, T is temperature, and k is\nphonon B\nBoltzmann constant (Chem. Mater. 30, 2374, 2018). Through fitting the\ntemperature-dependent FWHM curves, the extracted S factor and ℏω for the target\nphonon\nsamples are 24 and 20.5 meV, respectively, which are significantly lower than those of the\ncontrol samples (S = 38; ℏω = 25 meV) (Figs. R23b,c). These results confirm weaker\nphonon\nelectron–phonon coupling in the target sample, accounting for its narrower FWHMcompared\nto the control sample.\n360\n320\n280\n240\n40 80 120 160 200 240\nFigure R23. a, Pseudocolor maps of temperature-dependent PL spectra of (TPPEt) SbBr\n2 5\nand (TPPEtCz) Sb Br . b,c, FWHM of (TPPEtCz) Sb Br (b) and (TPPEt) SbBr (c) as a\n2 2 8 2 2 8 2 5\nfunction of temperature.\n34\n)Vem(\nMHWF\n800 (TPPEt)2SbBr5\n700\n600\n800\n700\n600\n80 120 160 200 240 280\n(TPPEtCz)2Sb2Br8\nS = 24.0 ± 0.9\nћwphonon = 20.5 ± 0.6 meV\nR2 = 0.994\nTemperature (K)\n)mn(\nhtgnelevaW\n1\n(TPPEtCz)2Sb2Br8\n).u.a(\nytisnetnI\nLP\n480\n440\n400\n360\n40 80 120 160 200 240\n)Vem(\nMHWF\na\nb c\n(TPPEt)2SbBr5\nS = 38.0 ± 1.4\nћwphonon = 25.0 ± 0.6 meV\nR2 = 0.990\nTemperature (K)\nOn the other hand, strong electron–phonon coupling induces lattice distortion upon\nphotoexcitation, leading to self-trapping of excitons at the potential energy minimum, which\ngives rise to the large Stokes shift. Specifically, A greater lattice distortion corresponds to a\nlarger Stokes shift (Adv. Mater. 34, 2201008, 2022). To clarify the origin of the Stokes shift\ndifference between two samples, we further investigated their lattice distortion behaviors. The\nangle distortion (σ2) and bond length distortion (Δd) were calculated using the following\nformulas:\n1 8\nσ2  (θ 90)2 (2)\n7 n\nn1\n1 5\nd  [(d d)/d]2 (3)\n5 n\nn1\nwhere θ is the Br−Sb−Br bond angle, and d and d are the length of the Sb−Br bonds and the\nn n\naverage length of the Sb−Br bonds, respectively. As shown in Fig. R24 and Tables R2,3, both\nσ2 and Δd are notably smaller in the target sample, confirming its more rigid lattice\nframework. The reduced lattice distortion consequently results in the observed smaller Stokes\nshift for target (TPPEtCz) Sb Br samples.\n2 2 8\nTo summarize, the combined evidences from temperature-dependent spectroscopy and\nstructural distortion analysis consistently demonstrate that the target (TPPEtCz) Sb Br\n2 2 8\nmaterial features weaker electron–phonon coupling and reduced lattice distortion, which\ncollectively explain its narrowband emission with smaller Stokes shift compared to the\ncontrol material.\nFigure R24. a,b, Structure of [SbBr ]2− (a) and [Sb Br ]2− (b) polyhedral.\n5 2 8\n5 2 8\n[SbBr ]2− [Sb Br ]2−\n5 2 8\nSb1−Br1 3.1481 Å 2.7363 Å\nSb1−Br2 2.8579 Å 2.8239 Å\nSb1−Br3 2.5709 Å 2.8616 Å\nSb1−Br4 2.7365 Å 2.7371 Å\nSb1−Br5 2.5062 Å 2.5283 Å\nΔd 0.006829 0.001778\nSb2−Br1 N/A 2.7362 Å\nSb2−Br7 N/A 2.8240 Å\nSb2−Br6 N/A 2.8616 Å\nSb2−Br4 N/A 2.7371 Å\nSb2−Br8 N/A 2.5283 Å\nΔd N/A 0.001784\nTable R3. The bond angles of [SbBr ]2− and [Sb Br ]2−.\n5 2 8\n[SbBr ]2− [Sb Br ]2−\n5 2 8\nBr5−Sb1−Br1 92.55° 89.62°\nBr5−Sb1−Br2 94.14° 89.71°\nBr5−Sb1−Br3 93.06° 91.53°\nBr5−Sb1−Br4 93.01° 92.1°\nBr1-Sb1-Br2 82.77° 88.18°\nBr2−Sb1−Br3 92.67° 90.09°\nBr3−Sb1−Br4 88.79° 88.66°\nBr4−Sb1−Br1 95.05° 93.03°\nσ2 18.34774 3.039486\nBr8−Sb2−Br1 N/A 89.62°\nBr8−Sb2−Br7 N/A 89.73°\nBr8−Sb2−Br6 N/A 91.54°\nBr8−Sb2−Br4 N/A 92.12°\nBr1−Sb2−Br7 N/A 88.18°\nBr7−Sb2−Br6 N/A 90.08°\nBr6−Sb2−Br4 N/A 88.65°\nBr4−Sb2−Br1 N/A 93.02°\nσ2 N/A 3.049286\nRevisions: The following sentences have been added in the Revised Manuscript.\nOn Page 11, line 170–174: “We also found that the (TPPEtCz) Sb Br sample features a\n2 2 8\nnarrower full-width at half-maximum (FWHM) and a smaller Stokes shift than the\n(TPPEt) SbBr (Supplementary Fig. 10), which is attributed to the weaker electron–phonon\n2 5\n36\ncoupling and reduced lattice distortion of the (TPPEtCz) Sb Br (Supplementary Figs. 11,12,\n2 2 8\nSupplementary Tables 5,6, and Supplementary Note 1).”\nSupplementary Figs. 10–12, Supplementary Tables 5, 6, and Supplementary Note 1 were\nadded in the Supporting Information.\nQ5. In the in-situ PL data shown in Fig. 2h, the PL intensity of TPPEtCz appears to be very\nstrong. Is this peak attributable to the inherently strong PL emission of the organic material\nitself? Furthermore, according to the experimental section, the spin-coating time is reported\nas 60 sec with an acceleration rate of 500 rpm/s, whereas the data presented in Fig. 2h only\ncovers the first 8 sec. Information on the subsequent time period is also important. How do\nthe crystallization process and optical properties evolve beyond this point? In addition, please\nprovide the optical properties before and after annealing for a more complete understanding.\nResponse: Thanks for your constructive comments. In Fig. 2h, the inherent PL peak located\nat ~400 nm is attributed to the TPPEtCz organic material itself. Moreover, according toyour\nconstructive suggestion, we supplemented the in-situ PL spectra after 8 s of spin-coating. As\nshown in Fig. R25a, the PL intensities of control (TPPEt) SbBr and target (TPPEtCz) Sb Br\n2 5 2 2 8\nsamples show negligible change beyond this time point, indicating that the crucial stages of\ncrystal nucleation and growth are predominantly completed within the first 8 s. To\nquantitatively analyze the crystallization kinetics during this initial period, we applied the\nAvrami model to investigate the crystallization rate of two films. The model is defined as kt =\n(−ln(1−α))1/n, where k is the effective reaction rate constant (crystallization rate constant\nherein), n is the Avrami exponent, t is time, and α is the conversion fraction characterized by\nthe PL intensity of the films (Angew. Chem. Int. Ed. 63, e202411361, 2024). From the PL\nintensity-time curves (Fig. R25b), two rate constants k and k can be fitted, which k\n1 2 1\ncorresponds to the growth of crystal nucleus, while k represents the Ostwald ripening\n2\nprocess. In comparison, the k (0.187 s−1) and k (0.018 s−1) values of the (TPPEtCz) Sb Br\n1 2 2 2 8\nare smaller than those of the control (TPPEt) SbBr (k = 0.246 s−1, k = 0.096 s−1). These\n2 5 1 2\nspecifically results show that TPPEtCz+ cations effectively retards the crystallization rate of\ncrystal nucleus, reducing crystal defects associated with non-radiative recombination induced\nby rapid crystallization, which is beneficial for improving the properties of films.\neffect of annealing treatment on the crystallization kinetics of the films. As shown in Figs.\nR25c,d, the PL intensities of two films decreased slightly over timewithout any peak shift,\nindicating that crystal nucleation and growth were essentially completed during the\nspin-coating stage, which is attributed to the rapid solvent evaporation of dichloromethane\nused in our experiment with a low boiling point. Notably, the (TPPEtCz) Sb Br films\n2 2 8\nexhibits a smaller decay of PL intensity compared to the control (TPPEt) SbBr films,\n2 5\ndemonstrating an enhanced resistance to thermal quenching. This improved thermal stability\naligns with suppressed non-radiative recombination pathways, as discussed in previous\nsections regarding the reduced electron−phonon coupling and lower defect density.\n800\n600\n400\n800\n600\n400\n0 10 20 30 40 50 60\nTime (s)\nFigure R25. a,b, In-situ PL spectra (a) and PL intensity evolution (b) of two films during the\nspin-coating process. c,d, In-situ PL spectra (c) and PL intensity evolution (d) of two films\nduring the annealing process.\nRevisions: The following sentences have been added in the Revised Manuscript.\nOn Page 12, line 203–207: “During the annealing process, the in-situ PL intensities of two\nfilms decreased slightly over time without any peak shift (Supplementary Fig. 16), indicating\nthat crystal nucleation and growth were essentially completed during the spin-coating phase,\nwhich is attributed to the rapid solvent evaporation of dichloromethane used in our\nexperiment with a low boiling point.”\nPage 9: Figs. 1h, i were replaced by new figures.\nSupplementary Fig. 17 was added in the Supporting Information.\n38\n)mn(\nhtgnelevaW\n1.0\n0.5\n0.0\n1.0\n0.5\n0.0\n0 1 2 3 4 5 6 7 8 9 56 57 58 59 60\n).u.a(\nytisnetnI\n800\n600\n)mn(\nhtgnelevaW\n800\n600\n400\n0 100 200 300 400 500 600\nTime (s)\n1.00\n0.75\n1.00\n0.75\n0 100 200 300 400 500 600\n).u.a(\nytisnetnI\na c\nSpin-coating Annealing\nPL@(TPPEt)2SbBr5\nPL@TPPEt\nPL@(TPPEtCz)2Sb2Br8\nPL@TPPEtCz\nb d\nPhase Ⅱ(Δt1 = 3.86 s)\nPhase Ⅱ (Δt3= 0.67 s, k2 = 0.096 s−1)\nPhase Ⅱ (Δt2 = 0.53 s, k1 = 0.246 s−1)\nPhase Ⅱ(Δt1 = 4.23 s) Phase Ⅱ (Δt3= 2.63 s,k2 = 0.018 s−1)\nPhase Ⅱ (Δt3= 2.63 s, k1 = 0.187 s−1)\nTime (s)"}, {"round": 2, "reviewer_comments": {"reviewer_1": "The authors have carefully revised the manuscript and provided substantial new experimental and analytical evidence to address the reviewers’ comments. In particular, the revised version clarifies the origin of the significantly enhanced electroluminescence efficiency by identifying interfacial π–π interactions between the carbazole-functionalized organic cation and the TPBi electron-transport layer as a key factor governing charge injection, transport, and recombination. The addition of appropriate control devices, including ZnO-based architectures that recover efficiencies comparable to earlier reports, strengthens the credibility of this interpretation. The incorporation of in situ photoluminescence studies, interfacial spectroscopy, impedance analysis, and device simulations provides a more comprehensive mechanistic picture linking cation design, crystallization behavior, interfacial energetics, and device performance. While the material platform builds upon prior work on carbazole-functionalized antimony halide hybrids, the revised manuscript now presents a clearer and more quantitatively supported advance in device physics and interface engineering, leading to record external quantum efficiency and operational stability for lead-free antimony halide LEDs. Overall, the revisions substantially improve the rigor and impact of the work and support its suitability for publication in Nature Communications.", "reviewer_2": "The authors have provided supportive data to address the proposed questions and further investigate the interaction between the organic-inorganic hybrid antimony halides and the electron-transport material TPBi. I am pleased to support the publication of this wonderful work. Prior to publication, I recommend that the authors examine the potential impact of solvent-ligand interactions on the reduced crystallization rate of (TPPEtCz)₂Sb₂Br₈, in addition to the hydrogen bonds between the ligands and the [Sb₂Br₈]²⁻ species. The TPPEtCz+ and TPPEt+ exhibit distinct interactions with dichloromethane, which may also play a significant role in the crystallization process.", "reviewer_3": "The authors have thoroughly addressed the reviewers’ concerns during the revision process. They have conducted additional experiments with care and have provided sufficient evidence to substantiate their explanations. The manuscript has been significantly strengthened, and the results are now presented with improved clarity and scientific rigor. Therefore, I find the revised version suitable for publication in Nature Communications."}, "author_response": "Point-by-point response\n(NCOMMS-25-52674-T)\nReviewer #1 (Remarks to the Author):\nThe authors have carefully revised the manuscript and provided substantial new experimental\nand analytical evidence to address the reviewers’ comments. In particular, the revised version\nclarifies the origin of the significantly enhanced electroluminescence efficiency by\nidentifying interfacial π–π interactions between the carbazole-functionalized organic cation\nand the TPBi electron-transport layer as a key factor governing charge injection, transport,\nand recombination. The addition of appropriate control devices, including ZnO-based\narchitectures that recover efficiencies comparable to earlier reports, strengthens the credibility\nof this interpretation. The incorporation of in situ photoluminescence studies, interfacial\nspectroscopy, impedance analysis, and device simulations provides a more comprehensive\nmechanistic picture linking cation design, crystallization behavior, interfacial energetics, and\ndevice performance. While the material platform builds upon prior work on\ncarbazole-functionalized antimony halide hybrids, the revised manuscript now presents a\nclearer and more quantitatively supported advance in device physics and interface\nengineering, leading to record external quantum efficiency and operational stability for\nlead-free antimony halide LEDs. Overall, the revisions substantially improve the rigor and\nimpact of the work and support its suitability for publication in Nature Communications.\nResponse: We sincerely thank the reviewer for their thoughtful and constructive assessment\nof our revised manuscript, and we are grateful for the reviewer’s recognition of the new\nexperimental and analytical evidence we have added. We also thank the reviewer for\nrecommending our manuscript to be accepted for publication by Nature Communications.\nThe authors have provided supportive data to address the proposed questions and further\ninvestigate the interaction between the organic-inorganic hybrid antimony halides and the\nelectron-transport material TPBi. I am pleased to support the publication of this wonderful\nwork. Prior to publication, I recommend that the authors examine the potential impact of\nsolvent-ligand interactions on the reduced crystallization rate of (TPPEtCz) Sb Br ,\nin\n2 2 8\naddition to the hydrogen bonds between the ligands and the [Sb Br ]2− species. The\n2 8\nTPPEtCz+ and TPPEt+ exhibit distinct interactions with dichloromethane, which may also\nplay a significant role in the crystallization process.\nResponse: We sincerely thank the reviewer for their positive evaluation and for supporting\nthe publication of our manuscript. We are also grateful for the thoughtful and insightful\nsuggestion regarding the potential impact of solvent-ligand interactions in influencing the\ncrystallization kinetics of (TPPEtCz) Sb Br .\n2 2 8\nAccording to your constructive advices, in the final version of the revised manuscript, we\nexamined the solvent-ligand interactions and discussed its mechanism in film formation and\ncrystallization analysis.We explicitly pointed out that, compared with TPPEt+, the stronger\nhydrogen interaction between the carbazole moiety in TPPEtCz+ and dichloromethane likely\nenhances solvation effect and moderates the crystallization process, working in synergy with\nthe hydrogen-bonding effects between the ligand and [Sb Br ]2− to yield a smooth, uniform\n2 8\nfilm.\nThank you again for this constructive comment, which helps deepen the mechanistic\ninterpretation of our results. We believe it strengthens the narrative and provides a useful\ndirection for future studies on solvent engineering in hybrid halide materials.\nRevisions: The following sentences have been added in the Revised Manuscriptto elaborate\nthe solvent-ligand interactions.\nOn Page 14, line 238–243: “Moreover, we examined the solvent-ligand interactions between\ndichloromethane (DCM) and organic components in the precursor solution. The 1H NMR\nresults show that, compared with TPPEt+, the stronger hydrogen interaction between the\ncarbazole moiety in TPPEtCz+ and DCM likely enhances solvation effect (Supplementary Fig.\n2\n22), which moderates crystallization process, working in synergy with the hydrogen-bonding\neffects between the organic and [Sb Br ]2− to modulate the crystallization kinetics.”\n2 8\nSupplementary Fig. 22 was added in the Supporting Information.\nThe authors have thoroughly addressed the reviewers’ concerns during the revision process.\nThey have conducted additional experiments with care and have provided sufficient evidence\nto substantiate their explanations. The manuscript has been significantly strengthened, and\nthe results are now presented with improved clarity and scientific rigor. Therefore, I find the\nrevised version suitable for publication in Nature Communications.\nResponse: We are very grateful to the reviewer for their positive and supportive final\nassessment of our revised manuscript. We sincerely thank you for agreeing to publish the\ncurrent manuscript in Nature Communications.\n4"}]

Decision letter