JOURNAL OF MOLECULAR STRUCTURE
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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 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
Journal of Physical Chemistry Letters
·
2020
·
IF 6.71
Chenkai Deng,Guojun Zhou,Da Chen,Jing Zhao,Yonggang Wang,Quanlin Liu
Organic–inorganic hybrid perovskites have aroused intense research interest because of their excellent physical performance and potential for use in optoelectronic field. Herein, we report two new 2D hybrid lead bromides, (C7H18N2)PbBr4 [C7H18N2 is 1,7-diaminoheptane] and (C9H22N2)PbBr4 [C9H22N2 is 1,9-diaminononane], both of which possess ⟨100⟩-oriented inorganic layers consisting of corner-sharing octahedra. The optical bandgaps are experimentally determined to be 2.76 eV for (C7H18N2)PbBr4 and 2.78 eV for (C9H22N2)PbBr4. Upon 390 nm excitation, (C7H18N2)PbBr4 exhibits white-light emission centered at 600 nm, and (C9H22N2)PbBr4 exhibits red-light emission centered at 620 nm. These broad photoluminescent spectra originate from the synergistic emission of free excitons (FEs) and self-trapped excitons (STEs). This work provides a strategy for realizing single-component white-light emission and efficient red-light emission in two-dimensional perovskites, demonstrating the vast application prospects of 2D perovskites in photoelectric devices.
研究领域:
材料科学
·
光电子学
·
无机化学
·
固体物理
✓ 已验证
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
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光电学
·
半导体物理
✓ 已验证
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2019
·
IF 10.159
Guojun Zhou,Xingxing Jiang,Maxim Molokeev,Zheshuai Lin,Jing Zhao,Jing Wang,Zhiguo Xia
Finding new low-dimensional metal halides with broad-band emission is attracting interest in single-component phosphor for white light-emitting diodes (WLEDs). The full-spectrum white light still remains a challenge as found in the two-dimensional hybrid material (C6H18N2O2)PbBr4 exhibiting the intrinsic free exciton (FE) and broad-band self-trap exciton (STE) emission upon 365 nm ultraviolet excitation, and a combined strategy has been proposed through doping the Mn2+ ions enabling a superposition of multiple emission centers toward the ultra-broad-band warm white light. The occupation of Mn2+ in (C6H18N2O2)PbBr4 has been discussed, and optical investigations verify that the warm white-light emission of Mn2+-doped (C6H18N2O2)PbBr4 originates from the coupling effects of the FE, STEs, and the 4T1–6A1 transition of the doped Mn2+. When the concentration of Mn2+ is 5%, the emission spectrum of the phosphor covers all visible-light areas with a full width at half maximum (FWHM) of about 230 nm. The high Ra (84.9) and warm light CCT (3577 K) values of the as-fabricated WLED lamp demonstrate that (C6H18N2O2)Pb1–xMnxBr4 can be promising as single-component white-light phosphor in solid-state lighting. Our work could provide a new understanding and perspective about hybrid metal halides for designing superior phosphor toward single-component white emission.
研究领域:
材料科学
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光电
·
固态照明
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2019
·
IF 2.687
Sen Yang,Shangxuan Huang,Qi Wang,Ruirui Wu,Qiuju Han,Wenzhi Wu
Cs 2 Ag x Na 1-x InCl 6 microcrystals (MCs) are synthesized using a solvothermal method. The regular variation of Na incorporation is characterized according to the intensity change of the X-ray diffraction and ultraviolet visible absorption peaks. Temperature-dependent photoluminescence (PL) properties of Cs 2 Ag x Na 1-x InCl 6 MCs are studied by use of steady-state PL and time-resolved PL (TRPL) measurements. From steady-state PL, it is verified that the white-light emission primarily originates from self-trapped excitons (STEs) at low temperature (80–290 K). When the electron-phonon interactions become stronger, STEs are promoted to generate from free excitons (FEs). And the high temperature-dependent (293–450 K) PL reveals the thermal quenching process. Temperature-dependent TRPL demonstrates that the change of lifetimes is attributed to band-edge FEs state and STEs state. It is found that the electrically-driven PL decreases to 70% then becomes stable from 0 to 120 min when light-emitting diodes (LEDs) are fabricated to explore the thermal stability. Our results suggest these white-emission Cs 2 Ag x Na 1-x InCl 6 MCs can be used as excellent materials for LEDs and provide reference to engineer such MCs toward practical optoelectronic applications .
研究领域:
材料科学
·
光电
·
光子学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）