JOURNAL OF MOLECULAR STRUCTURE
·
2024
·
IF 4
Yongfu Liang,Yuping Yang,Junbo Wang,Xuerui Cheng,Chaosheng Yuan,Xiang Zhu,Shiquan Feng,Zheng Wang,Haining Li,Huanjun Zhang
The structural versatility of organic compounds imparts manifold properties to hybrid organic−inorganic perovskites, where two-dimensional (2D) halide perovskites are potential future platforms for light-emitting devices because of their unique quantum well configuration and dielectric confinement. Notwithstanding the numerous studies on the organic−inorganic perovskites carried out to date, precisely charactering the structure and photoluminescence mechanism remain considerable challenges. Herein, by applying Rietveld refinement, we have obtained crystal structure and atomic sites of 2D layered OA 2 PbBr 4 perovskite , which undergoes a phase transition at 190 K with activation energies of 29.6 and 3.8 meV for the two phases, respectively. The theoretical analysis based on the crystal structure were performed to understand the nature of vibrations and band structure. Steady-state PL shows a narrow emission and a broad emission located at 409 and 487 nm, respectively. With temperature cooling down to 118 K, narrow emission gradually narrowed and enhanced. Meanwhile, intensity of broad emission first weakens and then increases. The turning point occurs near 198 K. By applying time-resolved PL (TRPL) and transient absorption (TA) spectra experiment, we observed a rapid carrier transfer from the FE to the STE state, and demonstrated the narrow and broad bands originate from free exciton and self-trapped exciton emission, respectively. And the self-trapping depth is proved to be 26.3 meV by low-temperature PL. Our findings indicate the synthesized 2D perovskite has potential applications in optoelectronic and display devices.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2024
·
IF 8
Yan Rong,Lingrui Wang,Yongheng Wang,Wenxin Wang,Jiaxiang Wang,Yifang Yuan,Urooj Shahzadi,Junnian Chen,Lei Zhang,Kai Wang,Haizhong Guo
Understanding the luminescence mechanics of metal halide perovskites is the key to uncovering the detailed pathways responsible for remarkable photophysical properties and engineering materials with enhanced optoelectronic properties. In this work, high pressure is employed to reveal the self-trapped exciton (STE) emission features of a 1D lead bromide perovskitoid (HM)Pb 2 Br 6 . Upon compression, a remarkable 42-fold enhancement in the intensity compared to the initial emission, along with exciton transfer from STE emission to narrow free exciton emission, is achieved in (HM)Pb 2 Br 6 . These phenomena are related to the anisotropic compression of (HM)Pb 2 Br 6 , which results in enhanced structural stiffness and a significant reduction in the distances of Pb─Pb bond lengths between inter-[Pb 2 Br 6 ] 2− chains, as well as Pb─Br bond lengths within the three basic intra-[Pb 2 Br 6 ] 2− octahedra. These results provide essential insights into the intriguing photophysics of STEs and shed new light on the dramatic exciton transfer to control and enhance the optical properties of the metal halide perovskites.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2020
·
IF 4.189
Bolin Guo,Chao Luo,Cheng Yan,Bai Sun,Wen Li,Weiqing Yang
Understanding excitonic behavior in light absorption and recombination process is urgently needed to regulate luminescent properties of two-dimensional (2D) perovskite; however, such information is still unexplored. Here, first, we demonstrate that pure phenethylamine lead bromine (PEA2PbBr4) nanosheets (NSs) possess strong exciton absorption and emission spectrum with high exciton binding energy (up to 310 meV) and prove that free excitons (FEs) play a decisive role in the optical transition process. Then, we design Cd-doped PEA2PbBr4 NSs to induce self-trapped excitons (STEs). Doping with isoelectric Cd naturally induces an impurity-driven lattice distortion and a strong exciton–phonon coupling, resulting in the STEs broadband extrinsic luminescence spectra. Further, the corresponding exciton fluorescent components of FEs and STEs can be effectively distinguished from the emission spectrum through spectral line-shape analysis, revealing the synergistic effect of exciton states in the recombination process. Unambiguously, this work will provide a deeper understanding of the exciton behavior and look forward to regulating exciton composition to obtain ideal luminescence properties.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Wen Li,Shiyu Yang,Bolin Guo,Xuehai Fu,Xiankan Zeng,Cheng Yan,Jingjing Cao,Qungui Wang,Weiqing Yang
Two-dimensional (2D) Ruddlesden-Popper hybrid organic-inorganic perovskites are the most promising candidates for highly efficient optoelectronic devices due to their remarkable exciton characteristics, adjustable band structure and long-term environmental stability. However, excitons emission behavior of 2D Ruddlesden-Popper perovskites is still unclear. Here we theoretically-experimentally decoupled the excitons behavior in 2D Ruddlesden-Popper PEA 2 PbI 4 nanosheets . Theoretically, the Elliott theory was used to separate exciton and band edge absorptions of PEA 2 PbI 4 nanosheets and determine an exciton binding energy of about 274 meV. Experimentally, spectral-dependent photoluminescence lifetime and excitation powder density-dependent photoluminescence spectra revealed that a distinct photoluminescence tail emission should be derived from localized excitons with lower emission energy than free excitons. Further, the luminescent component of the free excitons and localized excitons with their corresponding densities of states was theoretically decoupled by line-shape analysis of PEA 2 PbI 4 nanosheets photoluminescence spectra, which is consistent with the experimental results demonstrating the existence of localized excitons. Hence, our work provides understanding on the exciton behavior and luminescence mechanism of 2D Ruddlesden-Popper perovskites, which would benefit the prediction of high-performance excitonic devices based on 2D Ruddlesden-Popper perovskites.
研究领域:
材料科学
·
光学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
Energy Material Advances
·
2022
·
IF 0
Ming Shi,Bin Yang,Siping Liu,Ruiling Zhang,Keli Han,Can Li,Rengui Li
Single-component emitters with broadband emission are attractive but challenging for illumination and display applications. The two-dimensional organic-inorganic hybrid perovskites have exhibited outstanding broad emission property due to low electronic dimensionality and strong exciton-phonon coupling. However, few layered all-inorganic lead-free perovskites with broadband emission have been explored, and the explicit mechanism of exciton recombination in them also needs in-depth understanding. Herein, the inorganic bismuth-based perovskite Cs3Bi2Br9 achieves the stable broadband emission under ambient temperature and pressure by tuning the exciton recombination pathways via antimony (Sb) doping, and the photoluminescence quantum yield (PLQY) realizes an enhancement from 2.9% to 15.9%. The photoluminescence excitation (PLE) spectra indicate that the doped Sb introduces newly extrinsic self-trapped states. The incorporation of Sb promotes the transfer of free excitons (FEs) to extrinsic self-trapped excitons (STEs) observed from Sb content-dependent steady-state PL spectra and, meanwhile, reduces the nonradiative recombination of the generated extrinsic STEs, which are primarily responsible for the remarkably enhanced broad emission. Furthermore, femtosecond transient absorption results elucidate a clear exciton dynamics, in which the transition from FEs to STEs might arise through the gradient energy levels, and finally extrinsic STEs at various energy states contribute to the broadband emission.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
Nano Research
·
2023
·Vol. 16
·期 7
·10476-10482
·
IF 9.9
Li Xiaohan,Liu Aijun,Wang Zhaoyu,Wei Youchao,Lin Qun,Chen Yameng,Liu Yongsheng,Hong Maochun
Self-trapped excitons (STEs) emission from halide perovskites with strong exciton-phonon coupling has attracted considerable attention due to the widespread application in optoelectronic devices. Nevertheless, the in-depth understanding of the relationship between exciton-phonon coupling and luminescence intensity remains incomplete. Herein, a doping-enhanced exciton-phonon coupling effect is observed in Cs 3 Cu 2 I 5 nanocrystals (NCs), which leads to a remarkable increasement of their STEs emission efficiency. Mechanism study shows that the hetero-valent substitution of Cu + with alkaline-earth metal ions (AE 2+ ) causes a greater degree of Jahn–Teller distortion between the ground state and excited state structures of [Cu 2 I 5 ] 3− clusters as evidenced by our spectral analysis and first-principles calculations. As a consequence, an X-ray detector based on these Cs 3 Cu 2 I 5 :AE NCs delivers an X-ray imaging resolution of up to 10 lp·mm −1 and a low detection limit of 0.37 µGy air ·s −1 , disclosing the potential of doping-enhanced exciton-phonon coupling effect in improving STEs-emission and practical application for X-ray imaging.
研究领域:
材料科学
·
光学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 8
·3103-3113
·
IF 8.067
Yibing Wu,Rui Lin,Mudassir Iqbal,Yaocheng Jin,Yanping Huo,Xinhua Ouyang
A novel strategy of “Like–Likes–Like” is proposed to design and synthesize the electron transport materials (ETMs) and emitters for high-performance electroluminescent devices, including similar characteristics of structures, molecular orbitals, and ground/excited-states. Two novel compounds based on this strategy, PI–DPO–TPA and PI–DPO–PI, were successfully synthesized and applied to the fabrication of efficient organic light-emitting diodes (OLEDs). Both compounds cooperate well with each other from the perspective of exciton dynamics when respectively deposited as the non-doped OLED emitter and the ETM layers. Therefore, the devices exhibit an extremely low turn on voltage (2.0 V) and high efficiencies (18.87 cd A−1, 16.91 lm W−1, and 8.45%). In comparison, the control device with traditional ETM layers (i.e. TmPyPB) shows a relatively poor performance (4.5 V, 12.32 cd A−1, 4.02 lm W−1, and 4.20%). Furthermore, electron/hole-only devices, magneto-electroluminescence, and transient absorption spectra determine the contribution from the boosted formation of hot excitons, rather than the simply enhanced transport of a low-lying electron. The findings open a novel avenue to prepare ETMs and emitters for highly-efficient OLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2025
·
IF 7.2
Ou Xu,Xiaoyan Lu,Xiaodong Shen,Tongzhou Li,Bao Ke,Jialong Zhao,Bingsuo Zou
CsPbBr 3 nanocrystals (NCs) have attracted extensive attention due to their high color purity and good thermal stability. However, due to the quenching of surface defects, the photoluminescence quantum yields (PLQY) are low, and there are few previous comparative studies on the magnetic ion doping of powders and nanocrystals in this system. In this article, the effect of Cr 3+ doping CsPbBr 3 NCs and CsPbBr 3 powders and their PL properties is investigated. The successful doping of Cr 3+ is verified by TEM, SEM, and EDS characterization. At the appropriate amount of Cr 3+ , the PLQY of Cr 3+ doped CsPbBr 3 NCs achieves 96%, twice that of undoped CsPbBr 3 NCs. However, the PLQY of the CsPbBr 3 powder does not change much after Cr 3+ doping at its close emission wavelength. The electron paramagnetic resonance (EPR), temperature dependent PL and density functional theory (DFT) calculation show that the enhanced PL of doped CsPbBr 3 NCs is due to the formation of exciton magnetic polaron (EMPs), while the confined excitons in undoped NCs are multiple due to spin-orbit interaction. In CsPbBr 3 powders, both EMPs and antiferromagnetic excitons (AMPs) coexist and compete, verified by the PL decay curve, temperature variation spectra, and low temperature PL spectra in strong magnetic field.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-10
·
IF 14.7
Xu Bin,Li Yawen,Hong Peibin,Zhang Peijie,Han Jiang,Xiao Zewen,Quan Zewei
Hybrid metal halides represent a novel type of semiconductor light emitters with intriguing excitonic emission properties, including free exciton emission and self-trapped exciton emission. Achieving precise control over these two excitonic emissions in hybrid metal halides is highly desired yet remains challenging. Here, the complete transformation from intrinsically broadband self-trapped exciton emission to distinctively sharp free exciton emission in a quasi-one-dimensional hybrid metal halide (C 2 H 10 N 2 ) 8 [Pb 4 Br 18 ]·6Br with a ribbon width of n = 4, is successfully achieved based on high-pressure method. During compression, pressure-induced phonon hardening continuously reduces exciton–phonon coupling, therefore suppressing excitonic localization and quenching the original self-trapped exciton emission. Notably, further compression triggers excitonic delocalization to induce intense free exciton emission, accompanied with reduced carrier effective masses and improved charge distribution. Controlled high-pressure investigations indicate that the ribbon width of n > 2 is necessary to realize excitonic delocalization and generate free exciton emissions in similar quasi-one-dimensional hybrid metal halides. This work presents an important photophysical process of excitonic transitions from self-trapped exciton emission to free exciton emission in quasi-one-dimensional hybrid metal halides without chemical regulation, promoting the rational synthesis of hybrid metal halides with desired excitonic emissions.
研究领域:
材料科学
·
光电学
·
半导体物理
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 9
·期 1
·88-94
·
IF 7.059
Zhikai Qi,Yali Chen,Yao Guo,Xuelian Yang,Fu-Qiang Zhang,Guojun Zhou,Xian-Ming Zhang
One dimensional (1D) hybrid metal halides with core–shell quantum wire structures can display superior photoluminescence (PL) properties, e.g. high photoluminescence quantum yield and long lifetime; however, the single component white-light emissions in 1D hybrid systems composed of face-sharing octahedral chains have been only rarely reported. Herein, we report on a new 1D organic–inorganic hybrid cadmium chloride, (2cepiH)CdCl3 (2cepi = 1-(2-chloroethyl)piperidine), containing face-sharing CdCl6 octahedral chains. This incredible 1D Cd-based halide exhibited a bright white-light upon ultraviolet photoexcitation, which had an ultra-high color rendering index of 89 along with the CIE chromaticity coordinates of (0.27, 0.31). The fundamental mechanism of white-light emission was assigned to the synergistic emissions of free excitons and self-trapped excitons, as confirmed by the temperature-dependent PL spectra. To our knowledge, it is the first time that self-trapped exciton states are reported in 1D Cd-based hybrid materials with broadband white-light emission. Furthermore, both the experimental and the calculated results confirmed the semiconducting behavior of (2cepiH)CdCl3, and the band structure was determined by the inorganic frameworks. Our work provides a new idea to design novel single component white-light emitters.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Nano Energy
·
2021
·
IF 17.881
Hui Peng,Tao Huang,Bingsuo Zou,Ye Tian,Xinxin Wang,Yongchang Guo,Tiantian Dong,Zongmian Yu,Chunjie Ding,Fan Yang,Jianping Wang
Organic molecule incorporation into inorganic halide brings up a series of variable optical physics and applications. Here, we report a new zero-dimensional Mn-based hybrid metal halide of C 4 H 14 N 2 MnBr 4 single crystals by using bi-amine group organic ions incorporation, which shows bright orange emission at room temperature. Interestingly, it exhibits unique dual-emission bands at 516 nm and 623 nm, both bands are related to the polaronic exciton or selftrapped exciton(STE1) and the bipolaronic exciton(STE2) due to the enhanced charged electron-phonon coupling by the incorporation of bi-amine-group molecular ions in the manganese halide lattice, which are also combined with the d-d transition of single Mn and Mn pair at a Mn-Mn distance close to a critical number of about 6.6 Å. This distance is found to be the critical distance between Mn ions for their paramagnetic and pair ferromagnetic phases in the manganese halides. The temperature-dependent photoluminescence (PL) spectra show that the C 4 H 14 N 2 MnBr 4 single crystals have a sensitive reversible thermo-induced PL characteristic, i.e., its orange and green PL colors can be converted back and forth through the temperature dependent electron-phonon coupling coefficient variations, during which there are different phase transitions.
研究领域:
材料科学
·
光学物理
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Liming Zhang,Zhishan Luo,Wei Wang,Yulian Liu,Xin He,Zewei Quan
Zero-dimensional hybrid metal halides (0D HMHs) are attractive due to their intriguing self-trapped exciton (STE) emission properties. However, the effect of organic cations on the emission of 0D HMHs is relatively underexplored. Herein, we report two types of 0D hybrid tin bromides, (BMe)2SnBr6 (BMe = C8N2H18) and (MeH)2SnBr6 (MeH = C7N2H16), which share similar structural features with different hydrogen bonding (HB) interactions between [SnBr6]4– anions and organic cations. The (BMe)2SnBr6 with weak HB interactions exhibits only STE emission, while the (MeH)2SnBr6 exhibits both STE and charge transfer exciton emissions owing to the strong HB interactions, resulting in an excitation-dependent emission at cryogenic conditions. Detailed structural analyses and Hirshfeld surface calculations confirm that the enhanced HB interactions are essential to obtain the multiple emissions in (MeH)2SnBr6.
研究领域:
材料科学
·
光物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）