Self-trapped Excitons Research Articles

Enhanced Photodetection Performance of WSe2/V2O5 Nanocomposite on Flexible Substrate: Synergistic Advantages and Improved Efficiency.

The two-dimensional (2D) chalcogenide WSe2/V2O5 composite nanostructures were synthesized using the hydrothermal method and extensively characterized with various spectroscopic techniques. X-ray diffraction analysis confirmed the hexagonal crystal structure exhibiting space symmetry of P63/mmc. Scanning electron microscopy images provided insights into the irregular and nonuniform morphology. Optical spectrum analysis indicated a band gap value of 2.01 eV for 15% WSe2/V2O5 nanostructures, as determined by the Wood and Tauc equation. Photoluminescence (PL) excitation spectra at emission wavelengths of 550 and 750 nm exhibited broad emission attributed to self-trapped excitons for V2O5 and WSe2 nanostructures. Under excitation at λexc = 365 nm, PL emission spectra displayed distinct peaks at 550 and 750 nm, demonstrating the ability to emit vivid red light. A device optimized for photoresponsivity (R) of approximately 7.80 × 10-1 A W-1 and detectivity (D) of around 8.65 × 1011 Jones, and quantum efficiency of approximately 3.42 × 10-2 A W-1 were achieved at a wavelength of 390 nm while using a lamination sheet as a substrate. These findings underscore the capability of devices for efficient photoconversion at specified wavelengths, indicating potential applications in sensing, imaging, and optical communication. The photoresponsivity of the device remained stable at 3.38 × 10-3 A W-1 at 0° and 3.09 × 10-3 A W-1 at 55° bending angle. This indicates the resilience of device to mechanical strain, making it ideal for flexible and wearable sensor applications. The structural, morphological, and optical characterizations confirm the suitability of luminescent WSe2/V2O5 chalcogenide for practical optoelectronic applications, especially in display technologies.

The origin of broadband blue emission in zero-dimensional organic lead iodine perovskites: A first-principles study.

Broadband blue emission in zero-dimensional perovskites has received considerable attention, which is very important for the realization of stable blue-light emitters; however, the underlying formation mechanism remains unclear. Based on first-principles calculations, we have systematically studied the self-trapped excitons (STEs) behavior and luminescence properties in 0D-(DMA)4PbI6 perovskite. Our calculations show that there is a significant difference between the intrinsic STE luminescence mechanism (∼2.51eV) and experimental observations (∼2.70eV). In contrast, we found that the iodine vacancy (VI) is energetically accessible and exhibits a shallow charge transition level at ∼2.69eV (0/+1) above the valence band maximum, which provides the initial local well for the STEs formation. Moreover, the low electronic dimension synergistic Jahn-Teller distortion facilitates the formation of extrinsic excitons self-trapping. Further excited state electronic structure analysis and configuration coordinate diagram calculations confirmed that the broadband blue emission in 0D-(DMA)4PbI6 is the origin of VI-induced extrinsic STEs instead of intrinsic STEs. Therefore, our simulation results rationalize the experimental phenomena and provide important insights into the formation mechanism of STEs in low-dimensional perovskite systems.

Improving photoluminescence properties of lead-free Cs4SnBr6 zero-dimensional perovskite via Mn2+/Sb3+ Co-doping

Zero-dimensional tin-based halide perovskites have emerged as promising materials for optoelectronic applications owing to their outstanding optical properties. However, improving their PL efficiency and stability remains a significant challenge. Here, we demonstrate a novel codoping strategy by introducing Mn2+/Sb3+ ions to enhance both the PL intensity and thermal stability of Cs4SnBr6 perovskites. Our experiments reveal that Mn2+/Sb3+ incorporation increases light emission from self-trapped excitons (STEs) in Cs4SnBr6, achieving a PL quantum yield of approximately 67.7 %. Additionally, the doped samples show remarkable thermal stability. Detailed analyses, including X-ray diffraction, energy-dispersive spectroscopy, time-resolved PL, and temperature-dependent PL, suggest that the improved emission is driven by Mn2+/Sb3+-induced distortion of the [SnBr6]4- octahedra, which strengthens electron-phonon coupling and increases STE binding energy.

Crystal structure and optical properties of a new 0D Sb-based hybrid metal halide: (3,5-DMP)3Sb2Br9

Zero-dimensional (0D) lead-free hybrid organic-inorganic metal halides (OIMHs) have recently garnered tremendous attention due to their diversified structures and unique structure-dependent photoluminescent (PL) properties. Herein, we report a novel Sb-based 0D hybrid organic-inorganic metal halide (OIMH), with the chemical formula (3,5-DMP)3Sb2Br9 [3,5-DMP+ = 3,5-dimethyl piperidinium cation, C7H16N+]. The (3,5-DMP)3Sb2Br9 compound crystallizes in the triclinic crystal system (P1‾ space group), possessing a typical zero-dimensional (0D) structure with isolated face-sharing (Sb2Br9)3− bi-octahedral units encased by (3,5-DMP)+ organic cations. The isolated bi-octahedral units are distorted due to the strong stereochemical expression of the 5s2 lone pair on Sb3+ and intermolecular H-bonding between the organic moieties and inorganic clusters. The compound exhibited good thermal and environmental stability and possessed an indirect band gap of 2.92 eV. Upon 390 nm UV light excitation, the compound displayed a broad emission band centred at 555 nm, which was attributed to the self-trapped excitons (STEs) formed due to strong electron-phonon coupling in this compound. This study suggests the possibility of new types of 0D OIMHs by introducing different metal centers and bulky organic cations and provides a reference for the structure-property relationship in these compounds, thus, offering guidance for examining the structural evolution and improving their luminescent properties.

Selecting ns2 electron (Sb3+) and d3 electron (Cr3+) co-doped in lead-free halide double perovskite to achieve blue and near-infrared luminescence

The double-perovskite Cs2NaInCl6 has emerged as a highly favored candidate due to its remarkable stability and eco-friendly properties. However, it is noteworthy that this material does not demonstrate the desired optical performance in the crucial visible and near-infrared (NIR) spectrum, which may limit its potential applications in certain domains. We develop such characteristics in Cs2NaInCl6 by co-doping Sb3+ (s-electron) and Cr3+ (d-electron) ions. Doping with Sb3+ allows for 1S0→3P1 transition absorption, which then emits blue photoluminescence of self-trapped exciton (STE). By co-doping Sb3+ and Cr3+ ions, it causes the transfer of excitation energy from STE to Cr3+, yielding strong NIR emission at 950 nm. Temperature-dependent Photoluminescence (PL), PL excitation, PL decay and Tanabe-Sugano diagram provide insight into photophysical processes. Furthermore, a novel dual-modal optical information encryption based on the integration of blue and NIR luminescence printing patterns using Cs2NaInCl6: Sb3+ and Cs2NaInCl6: Sb3+/Cr3+, respectively, is successfully demonstrated.

Green massive mechanical synthesis of highly efficient Zn-Doped Cs3Cu2I5 for LED and X-ray imaging applications

As a new generation of environmentally friendly halide materials, Cs3Cu2I5 shows up the promising application in scintillation, LED, and photoelectric detection fields. However, liquid phase methods cannot produce Cs3Cu2I5 on a large scale, and the preparation process is accompanied by serious pollution. Although the ball milling method can solve the problems caused by the liquid phase synthesis method, the Cs3Cu2I5 obtained has many surface defects and low luminescence efficiency. In this work, a strategy of doping-assisted ball-milling synthesis using ZnI2 is proposed. Similar to the chemical preparation of Cs3Cu2I5, the iodine-rich environment during the modified ball milling process can also play a role in repairing surface defects. And it has been demonstrated through experiments and first principles calculations that the distortion of [Cu2I5]3- under ground/excited state can be adjusted through doping Zn into the Cu1 site, the formation barrier of self-trapped excitons is reduced, and the luminous efficiency of Cs3Cu2I5 is significantly improved. Subsequently, using the simple hot-pressing method, the representative Cs3Cu2I5:1.0Zn sample was combined with commercially available polypropylene to fabricate Cs3Cu2I5:1.0Zn@PP film. Finally, the potential applications of the newly-developed film in portable and customizable WLED and scintillation fields were explored.

Accumulation of oxygen interstitial-vacancy pairs under irradiation of corundum single crystals with energetic xenon ions

Single crystals of α-Al2O3 with broad sides oriented perpendicular to the c crystal axis have been irradiated by 231-MeV xenon ions with fluence varying from 5×1011 to 1014 ions/cm2. The spectra of radiation-induced optical absorption (absorption of a pristine crystal is subtracted) have been decomposed into Gaussians serving as a measure of oxygen-related Frenkel defects (vacancy-interstitial pairs). The concentration of all structural defects considered – vacancy-type F and F+ centers as well as oxygen interstitials – continuously increases with ion fluence. Therefore, radiation-induced origin of elementary absorption bands at 5.6 and 6.6 eV tentatively ascribed earlier to charged and neutral oxygen interstitials has been proved for the first time. The concentrations of charged interstitials (in the form of superoxide ions) have been directly determined by the EPR method. The evolution of cathodoluminescence bands typical of self-trapped excitons (VUV band at 7.6 eV) and F-type defects (bands peaked around 3.0 and 3.8 eV) with the rise of Xe-ion-irradiation fluence has been measured and analyzed.

Dual-Band Emission from Intrinsic and Extrinsic Self-Trapped Excitons in a Zero-Dimensional Copper Halide Cs3Cu2Br5.

Zero-dimensional Cs3Cu2X5 (X=Cl, Br, or I), the intensively studied light-emitting materials, generally exhibit single-band emissions from intrinsic self-trapped excitons (STEs), while defect-induced (extrinsic) STEs were considered nonemissive. Herein, we observed a dual-band emission from intrinsic and extrinsic STEs for Cs3Cu2Br5 at low temperature, and their emission mechanisms are elucidated. The intrinsic and extrinsic STEs are trapped from different initial states, with remarkably large trapping depths (>900 meV) evaluated at 50 K, indicating their negligible detrapping rates. In addition, the stronger electron-phonon coupling for extrinsic STE could shift the extrinsic STE band to intersect with the ground state in the configuration coordinate diagram, acting as a nonradiative pathway. This explains the vanishment of extrinsic STE emission at room temperature and the reported low photoluminescence quantum yields (<50%). With growing efforts to obtain multiple-band emitters, our insights into the emission mechanisms of intrinsic and extrinsic STEs provide valuable bases for further material engineering.

Self–Trapped Exciton versus Band–Edge Electron Transitions: Insights of the Factors Affecting the Optical Properties of Lead–Free Sn–Halide Perovskites

AbstractLead–free Sn–halide perovskites (Sn–HPs) are attractive photomaterials due to their lower toxicity, and some of them with higher stability against moisture and water, compared to their Pb‐based analogous. Interestingly, Sn‐HPs can exhibit two types of optical characteristics: the first scenario is known as band‐edge electron transitions [or band‐to‐band (b‐b) emission], where accumulated electrons in the conduction band recombine with holes in the valence band, providing a close separation between the absorption edge/photoluminescence (PL) peak (small Stokes shift). The second scenario is denominated as self‐trapped exciton (STE), where intraband gap energy states are formed to trap photocarriers generated in the perovskite, producing a broadband PL and a large Stokes shift. These optical features have been suitable for developing prominent devices, but there is no consolidated explanation about the key factors influencing the emergence of b–b emission or STE in Sn‐HPs, mainly the presence of these PL mechanisms in a particular perovskite system. This review highlights how the chemical composition, structural defects, and synthetic procedures are pivotal to producing Sn‐HPs with specific b–b or STE features. This will allow the preparation of Sn‐HPs with better quality/stability, and facile modulation of their PL properties, expanding their future applicability in LCD technologies.

Synthesis of low-dimensional metal halide CsAgCl2 for X-ray scintillation applications

Low-dimensional metal halides, which possess efficient luminescent properties, have garnered significant interest in the fields of optoelectronics and radiation detection. This study introduces novel lead-free silver-based metal halide material, CsAgCl2 microcrystals (MCs). These MCs have a one-dimensional atomic chain structure and a unique [AgCl5]4- tetragonal shared triangular configuration. CsAgCl2 MCs exhibit excellent performance as X-ray scintillators due to their bright broadband yellow emission and fast decay time in the microsecond range. The large Stokes shift of 350 nm is produced by self-trapped exciton emission. In X-ray scintillation applications, CsAgCl2 MCs demonstrate a high light yield of 13280 photons/MeV and a wide range of linear scintillation response. It is noteworthy that the CsAgCl2 MCs maintain good stability under both atmospheric conditions and continuous X-ray irradiation. The sample was used in an X-ray imaging screen, which clearly presented the X-ray projection image of a wooden stick. As a result, this research not only contributes to the collection of lead-free metal halide scintillators but also indicates that CsAgCl2 MCs have a wide range of future applications and potential in areas such as medical imaging, scientific research, and diagnostic and detection technologies.

In-Situ comparative study of photo-induced charge behavior in single-perovskite Cs3Bi2Br9 and double-perovskite Cs2AgBiBr6

While organic-inorganic lead halide perovskites excel in optoelectronic applications, their use is limited by toxicity and degradation. Consequently, lead-free alternatives like Cs2AgBiBr6, offering greater stability and diverse applications, have been investigated. However, the fundamental structural, optical, and electronic properties of Cs2AgBiBr6 remain insufficiently understood. In this study, we compared the exciton dynamics and photo-induced charge separation in Cs3Bi2Br9 and Cs2AgBiBr6 films using in-situ surface techniques. Both materials display similar surface photovoltage (SPV) peaks in the 450–500 nm range, supporting the hypothesis of Bi 6s-6p orbital transitions in distorted [BiBr6]3− structures. Although many theories propose the presence of self-trapped excitons (STE) in bismuth-based perovskites, sufficient evidence has been lacking. Our observation of a significant redshift in the SPV peak compared to the band edge absorption peak supports STE hypothesis, with Cs2AgBiBr6 showing a more pronounced redshift due to its more complex electronic structure and stronger electron-phonon coupling. Additionally, we observed that Cs2AgBiBr6 exhibits superior charge separation efficiency compared to Cs3Bi2Br9. Notably, Cs2AgBiBr6 shows significantly shorter rise times, indicating more rapid photogenerated charge separation. However, both materials exhibit similar fall times, suggesting comparable charge recombination rates. Light-chopping-frequency dependent SPV measurements further reveal that Cs2AgBiBr6 has a higher charge separation rate than Cs3Bi2Br9. These findings underscore the potential of bismuth-based perovskites for optoelectronic applications and highlight the importance of a comprehensive understanding of their structure-property relationships.

Achieving efficient self-trapped excitons emission by suppressing defect level in Sb3+ doped metal halide

The field of metal halide engineering has made considerable progress, yet additional studies are needed to completely grasp the intriguing principles that govern their luminescence. In this work, we report a novel zero-dimensional (0D) organic-inorganic metal halide hybrid (OIMH) (C3H12N2)2InCl7 (C3H12N2 = 1,3-propane diamine cation) and reveal its interesting luminescent properties through experimental research and theoretical calculations. The photoluminescence (PL) of (C3H12N2)2InCl7 is a synergistic combination of intrinsic self-trapped exciton (STE) emission and defect-bound exciton (DBE) emission. Doping with Sb3+ induces several changes in (C3H12N2)2InCl7, including defect passivation, a reduction in the band gap, and structural shrinkage. These modifications result in a transition of PL centers to external STE emission, with the photoluminescence quantum yield (PLQY) increasing from 4.44 % to 68.70 %. Our work proposes, for the first time, the synergistic emission of STE and DBE and reveals the effect of metal ion doping, providing new insights into the mechanisms of materials exhibiting multifunctional exciton emission.

Photoluminescence decay of mobile carriers influenced by imperfect quenching at particle surfaces with subdiffusive spread.

We recently presented a quantitative model to explain the particle-size dependence of photoluminescence (PL) quantum yields and revealed that exciton quenching is not diffusion controlled, but limited by surface reactions. However, the exciton decay kinetics has not been analyzed yet using our theoretical model. Here, we study kinetic aspects of the model and show that it should be extended to take into account subdiffusion rather than normal diffusion to maintain consistency with the observed complex decay kinetics; we also show that the PL decay kinetics is nonexponential even when the PL quenching is limited by surface reactions under subdiffusion. Our theoretical analysis of the PL quantum yield and the PL decay kinetics provides a comprehensive picture of mobile charge carriers, immobile polarons, and self-trapped excitons.

White light emission in Bi3+/Te4+ co‐doped Cs2SnCl6 for adjustable daily lighting and visible light communication

Abstractns2 ions‐doped lead‐free perovskites have garnered significant attention for their potential in diverse optoelectronic applications, owing to their broad emission characteristics arising from self‐trapped excitons (STEs). Herein, high‐performance white light‐emitting diodes (WLEDs) for intelligent lighting are developed by Bi3+/Te4+co‐doped Cs2SnCl6. Effective energy transfer between the dual STE emissions results in tunable broadband emissions covering the full‐color region. Adjustable WLEDs containing cold‐ and warm‐white lighting are fabricated. The WLEDs have excellent luminescent performances coupled with adjustable correlated color temperatures of 6417 and 3829 K. This versatility allows them to meet lighting demand for different scenarios, which is essential for future WLEDs to achieve healthy lighting. In addition, the excellent white light emission characteristics can also be applied in the visible light communication (VLC) system, achieving a −3 dB bandwidth of 13.3 MHz and opening eye diagrams in the data rate range of 10–60 Mbps. This work represents a significant advancement toward building intelligent health lighting applications and achieving high‐quality light sources for VLC based on lead‐free perovskites.

Light emission from multiple self-trapped excitons in one-dimensional Ag-based ternary halides

Abstract Ternary metal halides based on Cu(I) and Ag(I) have attracted intensive attention in optoelectronic applications due to their excellent luminescent properties, low toxicity, and robust stability. While the self-trapped excitons (STEs) emission mechanisms of Cu(I) halides are well understood, the STEs in Ag(I) halides remain less thoroughly explored. This study explores the STE emission efficiency within the A 2AgX 3 (A = Rb, Cs; X = Cl, Br, I) system by identifying three distinct STE states in each material and calculating their configuration coordinate diagrams. We find that the STE emission efficiency in this system is mainly determined by STE stability and influenced by self-trapping and quenching barriers. Moreover, we investigate the impact of structural compactness on emission efficiency and find that the excessive electron–phonon coupling in this system can be reduced by increasing the structural compactness. The atomic packing factor is identified as a low-cost and effective descriptor for predicting STE emission efficiency in both Cs2AgX 3 and Rb2AgX 3 systems. These findings can deepen our understanding of STE behavior in metal halide materials and offer valuable insights for the design of efficient STE luminescent materials. The datasets presented in this paper are openly available in Science Data Bank at https://doi.org/10.57760/sciencedb.12094.

In Situ Fabrication of Highly Efficient and Stable Cs2NaInCl6: Sb3+@PVDF Composite Films for Optoelectronic Devices.

Lead-free double perovskites (DPs) have superior phase stability and optical properties, which make them competitive for future applications in illumination and displays. However, the preparation of DPs was mainly based on high-temperature heating and hydrochloric acid as a solvent to form powders, which increased the risk and cost of the preparation process and limited its further application. In this study, the growth of Cs2NaInCl6: Sb3+ DPs in polyvinylidene difluoride (PVDF) films was achieved using an in situ fabrication strategy with DMSO as the solvent. The prepared Cs2NaInCl6: Sb3+@PVDF composite films (CFs) can achieve a bright blue emission under 302 nm irradiation. To achieve the optimal luminescent performance of CFs, the photoluminescence (PL) intensity of Cs2NaInCl6: Sb3+@PVDF CFs under various in situ preparation conditions was compared. In addition, the photoluminescence quantum yield (PLQY) of CFs was increased from 0.72% to 83.77% by adjusting the doping amount of Sb3+, and the fluorescence lifetimes t1 and t2 were 131.08 and 1048.52 ns, respectively. Temperature-dependent PL spectroscopy and density functional theory (DFT) calculations indicate that these excellent optical properties are derived from the self-trapped excitons (STEs) at the [SbCl6]3- octahedron and [InCl6]3- octahedron connected via Cl-Na-Cl. The CFs also demonstrated excellent environmental stability, maintaining a relatively stable PL intensity even under conditions of water immersion, high temperatures, and ultraviolet (UV) radiation. Finally, we used the CFs to assemble a blue light-emitting device (LED), which showed good and stable blue emission performance at different currents. This work can provide a new idea for preparing DPs, which is conducive to promoting their commercial application in high-performance optoelectronic devices.

Ultrabroad Near Infrared Emitting Perovskites

Phosphor converted light emitting diodes (pc‐LEDs) have revolutionized solid‐state white lighting by replacing energy‐inefficient filament‐based incandescent lamps. However, such a pc‐LED emitting ultrabroad near‐infrared (NIR) radiations still remains a challenge, primarily because of the lack of ultrabroad NIR emitting phosphors. To address this issue, we have prepared 2.5% W4+‐doped and 2.8% Mo4+‐doped Cs2Na0.95Ag0.05BiCl6 perovskites emitting ultrabroad NIR radiation with unprecedented spectral widths of 434 and 468 nm, respectively. Upon band‐edge excitation, the soft lattice of the host exhibits broad self‐trapped exciton (STE) emission covering NIR‐I (680 nm), which then nonradiatively excites the dopants. The π‐donor ligand Cl⁻ reduces the energy of dopant d‐d transitions emitting NIR‐II with a peak at ~950 nm. Vibronic coupling broadens the dopant emission. The large spin‐orbit coupling and local structural distortion might possibly enhance the dopant emission intensity, leading to an overall NIR photoluminescence quantum yield ~40%. The composite of our ultrabroad NIR phosphors with biodegradable polymer polylactic acid could be processed into free‐standing films and 3D printed structures. Large (170 × 170 mm2), robust, and thermally stable 3D printed pc‐LED panels emit ultrabroad NIR radiation, demonstrating NIR imaging applications.

Ultrabroad Near Infrared Emitting Perovskites.

Phosphor converted light emitting diodes (pc-LEDs) have revolutionized solid-state white lighting by replacing energy-inefficient filament-based incandescent lamps. However, such a pc-LED emitting ultrabroad near-infrared (NIR) radiations still remains a challenge, primarily because of the lack of ultrabroad NIR emitting phosphors. To address this issue, we have prepared 2.5 % W4+-doped and 2.8 % Mo4+-doped Cs2Na0.95Ag0.05BiCl6 perovskites emitting ultrabroad NIR radiation with unprecedented spectral widths of 434 and 468 nm, respectively. Upon band-edge excitation, the soft lattice of the host exhibits broad self-trapped exciton (STE) emission covering NIR-I (700 nm), which then nonradiatively excites the dopants. The -donor ligand Cl- reduces the energy of dopant d-d transitions emitting NIR-II with a peak at ~950 nm. Vibronic coupling broadens the dopant emission. The large spin-orbit coupling and local structural distortion might possibly enhance the dopant emission intensity, leading to an overall NIR photoluminescence quantum yield ~40 %. The composite of our ultrabroad NIR phosphors with biodegradable polymer polylactic acid could be processed into free-standing films and 3D printed structures. Large (170 170 ), robust, and thermally stable 3D printed pc-LED panels emit ultrabroad NIR radiation, demonstrating NIR imaging applications.

Structure Evolution and Optical Tuning of One-Dimensional Post-perovskite (TDMP)PbBr4 under High Pressure.

Optimizing the structure and tuning the optical properties in low-dimensional organic-inorganic halide perovskites are crucial to practical applications for stable solid-state lighting. Herein, we performed high-pressure investigations on one-dimensional (1D) postperovskite (TDMP)PbBr4 (TDMP = trans-2,5-dimethylpiperaziniium), and structure and optical properties under pressure are studied. (TDMP)PbBr4 exhibits color tunable emission from cool white light to yellow orange as the pressure increases from atmospheric pressure to 20.0 GPa. It was found that high pressure would facilitate trapping the free exciton (free exciton) to form a self-trapped exciton (STE) state due to increased electron-phonon interaction, thus enhancing STE emission in the pressure range of 4.0-7.0 GPa. At above 7.0 GPa, the STE emission is quenched, which is due to the phonon-assisted nonradiative relaxation. Meanwhile, (TDMP)PbBr4 displays reversible piezochromism from colorless to yellow under pressure as a result of the compound undergoing a reversible structural transformation. This work provides an insightful perspective on revealing the relationship between structure and optical properties of 1D postperovskites under high pressure.

Toward an Ideal Light Source for Indoor Photosynthesis: Broadband Red Emission in Zero-Dimensional Hafnium-Based Metal Halide (TPP)2HfCl6·4C2H3N:Sb3.

With suitable electron-phonon coupling strength, a near-unity broadband photoluminescence quantum yield (PLQY) can be achieved in organic-inorganic hybrid metal halides (OIHMHs) via self-trapped exciton (STE) emission. However, it is still challenging to obtain high-quality red emission from OIHMHs with a desirable emission wavelength and high chemical stability, which hinders their practical application in high-performance displays, plant-growth lighting, and biomedical imaging. Herein, a series of hafnium-based zero-dimensional (TPP)2HfCl6·4C2H3N (TPP: tetraphenylphosphonium) single crystals with different Sb3+ doping levels are synthesized. The Sb3+-doped (TPP)2HfCl6·4C2H3N shows dual-band red emission with a full width at half-maximum of 178 nm and a high PLQY of 91.09%. This broad dual-band emission originates from dopant-induced extrinsic free excitons and STEs. Furthermore, (TPP)2HfCl6·4C2H3N:Sb3+ was employed as a luminescence converter in a light-emitting diode (LED) for plant growth regulation. A correlated color temperature of 4055 K and a color rendering index of 82.13 were achieved upon excitation of the LED at 365 nm. These results provide fundamental perspectives on the emission behavior of Sb3+-doped OIHMHs and illustrate their promise for use in plant-growth lighting.