JOURNAL OF CHEMICAL PHYSICS
·
2024
·Vol. 160
·期 16
·
IF 3.1
Du Luchao,An Jie,Katayama Tetsuro,Duan Menghan,Shi XiaoPing,Wang Yunpeng,Furube Akihiro
In recent years, all-inorganic perovskite materials have become an ideal choice for new thin film solar cells due to their excellent photophysical properties and have become a research hotspot. Studying the ultrafast dynamics of photo-generated carriers is of great significance for further improving the performance of such devices. In this work, we focus on the transient dynamic process of CsPbBr 3 /TiO 2 composite systems with different Mn 2+ doping contents using femtosecond transient absorption spectroscopy technology. We used singular value decomposition and global fitting to analyze the transient absorption spectra and obtained three components, which are classified as hot carrier cooling, charge transfer, and charge recombination processes, respectively. We found that the doping concentration of Mn 2+ has an impact on all three processes. We think that the following two factors are responsible: one is the density of defect states and the other is the bandgap width of perovskite. As the concentration of doped Mn 2+ increases, the charge transfer time constant shows a trend of initially increasing, followed by a subsequent decrease, reaching a turning point. This indicates that an appropriate amount of Mn 2+ doping can effectively improve the photoelectric performance of solar cell systems. We proposed a possible charge transfer mechanism model and further elucidated the microscopic mechanism of the effect of Mn 2+ doping on the interface charge transfer process of the CsPbBr 3 /TiO 2 solar cell system.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2025
·
IF 3.2
Yushuai Jia,Liping Xu,Jiale Chen,Yueyuan Zeng,Zhihong Duan,Taifeng Liu,Xin Liu
Defect engineering can effectively promote light absorption and carrier dynamics of semiconductor photocatalysts. However, it is still difficult to modulate the distribution and concentration of defects in the photocatalyst via a facile strategy. The perovskite SrTiO3 is a promising semiconductor photocatalyst for hydrogen production, but its performance is restricted by limited UV absorption and severe carrier recombination. Herein, we develop a visible light-responsive SrTiO3 photocatalyst with Ti3+ and oxygen vacancies distributed both in the bulk and on the surface through a solvothermal synthesis coupled with light illumination. In situ EPR and XPS disclose that bulk defects are produced during the solvothermal synthesis, while the surface defects can be generated by light irradiation. The concentration of Ti3+ and oxygen vacancies can be facilely adjusted by varying the solvothermal time, resulting in the regulation of visible absorption in the range of 450–650 nm. Density functional calculations demonstrate the formation of an in-gap band consisting of defect energy levels, which induces a two-step electron transition and accounts for the visible light response. As revealed by synchrotron radiation X-ray absorption spectroscopy, ultrafast transient absorption spectroscopy, and electrochemical analysis, the increase of defect concentration leads to the decrease of Ti–O coordination number as well as the increase of carrier lifetime and carrier density, which ensures promoted carrier dynamics and boosted hydrogen evolution activity driven by visible light. The present research uncovers the role of defects in tuning light absorption and carrier dynamics and opens new opportunities for achieving highly efficient solar energy conversion.
研究领域:
材料科学
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能源化学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Linjie Fan,Yixun Cao,Yushuai Jia,Ruolan Zhu,Deji Zhang,Xin Liu
Engineering of the defective structure and crystallinity of semiconductor photocatalysts to promote carrier dynamics has attracted considerable attention. This study presents the design of surface nitrogen defect modified crystalline carbon nitride spheres (QCN) with synergistically boosted surface and bulk carrier separation through a rapid thermal treatment coupled with a flux assisted strategy. Using supramolecular self-assembled polymer as the precursor, spherical crystalline CN heterojunctions are firstly prepared by a molten salt method to improve the separation of bulk carriers. Abundant nitrogen defects are then introduced onto the surface of crystalline CN through the following quick thermal treatment in air, which can generate a higher exciton density and drive rapid migration of surface carriers by acting as effective electron sinks. Furthermore, the defect level also improves the visible light utilization and provides more active centers for reactant adsorption and activation. As a result, QCN samples exhibit excellent performance in photocatalytic hydrogen evolution, with an optimal hydrogen production rate 4.3 times higher than that of pristine bulk CN under visible light irradiation. Moreover, the photocatalytic activities of QCN are dependent on the concentration of nitrogen defects, which can be flexibly adjusted via thermal treatment temperature. Such a two-step regulation strategy combining the distinctive advantages of surface defect structure and high crystallinity is beneficial for synergistic enhancement of photocatalytic performance, and provides new insights for sustainable energy production in the future.
研究领域:
材料科学
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能源科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Chemistry
·
2020
·
IF 7.216
Xuedong Jing,Na Lu,Jindou Huang,Peng Zhang,Zhenyi Zhang
Engineering lattice defects in two-dimensional (2D) sulfide semiconductors has been accepted as an effective strategy to enhance the efficiency of the solar-to-fuels conversion. Although many researches have proven the lattice defect-mediated photocatalytic activity of ZnIn 2 S 4 , the artificial control of S-defects for optimizing the charge-carrier kinetics process in ZnIn 2 S 4 has long been a challenging task. Herein, we report a facile one-step method to modulate the lattice S-content of ZnIn 2 S 4 microflowers (MFs) only through adjusting the used amount of S-precursor in the hydrothermal solution that contains the metal precursors with a fixed Zn/In stoichiometric ratio at 1:2. We also demonstrated that the S-vacancies at the In facets were the main type of lattice defects in the formed ZnIn 2 S 4 MFs, which could enhance both the separation and migration processes of the photoinduced charge-carriers due to the existence of discrete defect energy-levels (DELs) and the reduced effective mass of electrons, as evidenced by the first-principles calculations and the electron spectra analyses. The ZnIn 2 S 4 MFs with the optimal content of S-vacancy obtained by a hydrothermal treatment of the precursors with the Zn/In/S stoichiometric ratio of 1:2:8 possessed the long-lived photoinduced electron (~94.64 ns) for contributing to the photo-physical and -chemical processes. Thus, upon visible light irradiation, the H 2 -evolution rate of this sample reached ~ 2.40 mmol h −1 g −1 with an apparent quantum efficiency of ~ 0.16% at 420 nm even though only using 5 mg of photocatalysts without any cocatalysts .
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
Laser & Photonics Reviews
·
2023
·Vol. 17
·期 12
·2300533
·
IF 11
Peipei Ma,Lihe Yan,Jinhai Si,Tianyu Huo,Zhenqiang Huang,Wenjiang Tan,Jin Xu,Xun Hou
Single-crystal halide perovskites are among the most promising semiconductor candidates for highly efficient optoelectronic devices due to their higher stability against moisture and light radiation and lower trap density than their polycrystalline counterparts. In this work, single-crystal MAPbBr 3 microcavities with controllable geometries and sizes are fabricated using a template-limited method combined with an anti-solvent diffusion growth method. The single-crystal microcavities emit lasers around 550 nm under femtosecond laser excitation, with a lasing threshold of ≈35 µJ cm −2 and a quality factor of 1135, as well as excellent long-term operation stability. The temporal-spatial evolution of the lasing process in an individual microcavity is achieved by the microscopic optical Kerr-gating technique. The temporal behaviors including pulse duration and build-up time, emission spectra shift, and lasing mode evolution as a function of pump fluence are unveiled, and the complex relationship between the light-induced carrier dynamics and lasing properties is clarified. Spatial heterogeneous lasing dynamics are also observed in an individual microdisk, which is attributed to the non-uniform optical losses and carrier densities driven by structural imperfections. This study can provide a fabrication strategy for perovskite on-chip optoelectronic devices, as well as a deeper understanding of the carrier-density-driven lasing dynamics in microcavities.
研究领域:
材料科学
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光学
·
半导体物理
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Jianhua Xiao,Jiaao Wu,Fangchen Zhu,Jiehao Ke,Qingxia Liu,Yang Wang,Liu Yuan,Huiling Tai,Yadong Jiang
Bias-switchable dual-mode organic photodiodes (OPDs) that integrate photovoltaic and photomultiplication modes are recently developed and shown prospects in complex light-intensity applications. Yet, the device physics that focuses on carrier dynamics is still a challenge and needs to be further explored. Herein, dual-mode OPDs are developed through interface layer manipulation, that is, introducing cathode interface layers (typically, Zn x O:D149) with deep energy levels and abundant bulk defects and an anode interface layer of thermally-evaporated ZnO (e-ZnO) with a wide bandgap. Under reverse bias, Zn x O:D149 forms a barrier wall to effectively block external holes and maintain the photovoltaic mode of the OPDs. Under forward bias, the capturing effect of Zn x O:D149 and blocking effect of e-ZnO help to reduce the dark current; when under illumination, defect traps capture photo-generated holes, eliminating the barrier traps and promoting unobstructed injection of external carriers to achieve photomultiplication effect. The typical device delivers high specific detectivity (>10 12 Jones) and fast response (<40 µs), and exhibits disparate external quantum efficiency in two operating modes, showing promise for simultaneously detecting faint and strong light. This general strategy for preparing dual-mode OPDs is compatible with CMOS processing technology and meets the miniaturization and integration requirements of next-generation detection systems.
研究领域:
材料科学
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光电子学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PHYSICS LETTERS
·
2022
·
IF 2.719
Cheng Li,Cheng Luo,Wei Zhou,Ruiling Zhang,Daoyuan Zheng,Peigeng Han
Lead-free vacancy-ordered quadruple perovskites have received extensive attention in optoelectronic applications. We study the optical properties and charge-carrier dynamics of Cs 4 Mn(Bi 1-x Sb x ) 2 Cl 12 (0 ≤ x ≤ 1) quadruple perovskite single crystals (SCs), which exhibit excellent stability and Mn 2+ -based photoluminescence (PL) emission. The ratio of Bi:Sb has a great influence on PL intensity. As the Bi 3+ content increases, the PL quantum yield (PLQY) shows a monotonically increasing trend and enhances by more than 40 times, attributed to larger energy difference between conduction band minimum and 4 T 1 state of Mn 2+ ions, weaker Mn-Mn coupling interaction due to longer Mn···Mn distance and smaller Jahn-Teller distortion, and lower carrier-phonon coupling. Moreover, Cs 4 Mn(Bi 1-x Sb x ) 2 Cl 12 nanocrystals were synthesized through top-down ultrasonic crushing method. The PL quenching of Cs 4 MnBi 2 Cl 12 nanocrystals compared to corresponding SCs arises from surface defect trapping. Our work provides an in-depth understanding of Mn 2+ -based PL mechanism.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2019
·
IF 2.687
Mingrui Tan,Ning Sui,Qinghui Liu,Zhihui Kang,Lin Wang,Wenquan Wang,Qiang Zhou,Hanzhuang Zhang,Yinghui Wang
Low-toxicity zinc blende Mn–CuInS (MCIS) thin films and a corresponding optical switch were fabricated and examined using multiple measurements. Transient absorption spectroscopy indicated that multiple carrier processes occurred during carrier relaxation. The optical switch devices showed good responsivity and stability. The kinetics of the photo-generated charge carriers were affected by carrier concentration and showed no electric-field dependence. These prepared devices showed potential for rapid photodetection applications.
研究领域:
材料科学
·
光学工程
·
半导体物理
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2020
·
IF 4.3
Qun Wang,Ming Ma,Xiaohong Wu,Wei Qin
Understanding carrier dynamic behavior including carrier lifetime and concentration, electrochemical behavior and band structure of the MAPbX 3 (X = I, Br) with high crystal quality are important for improving photocatalytic applications. Herein, a facile isopropanol-assisted solvothermal strategy was demonstrated for highly yielding synthesis MAPbX 3 (X = I, Br) cubic microcrystals with high crystallinity for degrading water insoluble dyes in an organic solvent system. Supported by time-dependent morphology evolution experimental evidence, a high temperature gradient inside the solution leads to natural convection which can induce the screw dislocation in microcrystals. The XRD, IR, steady-state photoluminescence (PL) spectra, fluorescence lifetimes UV–vis spectra and electrochemical tests were investigated to found a direct correlation between crystal quality (crystallinity and defects) and optical properties (PL intensity and bandgap). Importantly, MAPbBr 3 displayed almost an order of magnitude more efficient photocatalytic degradation of malachite green (MG) dye in isopropanol solvent relative to those of MAPbI 3 , which was ascribed to good stability and superior photoinduced electron transfer for molecular oxygen activation.
研究领域:
材料科学
·
化学
·
光催化
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 17
·6064
·
IF 3.4
Menghan Duan,Yunpeng Wang,Pingli Zhang,Luchao Du
Organic inorganic perovskite materials have received increasing attention in the optoelectronic field because of their unique properties. The ultrafast dynamics of photogenerated carriers determine photoelectric conversion efficiency, thus, it is feasible to influence the dynamics behavior of photogenerated carriers by regulating A-site cations. This paper mainly used transient absorption spectra (TAS) technology to study the photogenerated carriers relaxation processes of organic–inorganic perovskite CsxMA1−xPbI3materials at different x values. Three sets of time constants were obtained by global fitting at different values of x. The experimental results showed that the crystal structure of perovskite could be affected by adjusting the Cs+doping amount, thereby regulating the carrier dynamics. The appropriate amount of A-cation doping not only maintained the organic–inorganic perovskite crystal phase, but also prolonged the photogenerated carrier’s lifetime. The 10% Cs+doping CsxMA1−xPbI3perovskite has potential for solar cell applications. We hope that our research can provide dynamics support for the development of organic–inorganic perovskite in solar cells.Keywords:Cs+doping MAPbI3perovskite;transient absorption spectra;crystal structure;carriers dynamics
研究领域:
材料科学
·
光电子学
·
太阳能电池研究
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2025
·
IF 3.2
Lihong Qi,Song Wang,Hongyan Li,Ruiji Sun,Yi Wu,Ruirui Wang,Liangying Hua,Ying Xie,Kai Pan
Lead-free double perovskite nanocrystals (NCs) have garnered significant attention due to their ability to address the toxicity and instability issues associated with lead-based perovskite NCs. Herein, we have successfully synthesized a series of Cs2AgBiBr6 NCs with varying concentrations of In3+ alloying, achieved through a colloidal solution method. These NCs consistently exhibit a monodisperse, uniform cubic morphology. By meticulously adjusting the alloying concentration of In3+, we have significantly enhanced the luminescence performance of Cs2AgBiBr6 NCs, achieving a maximum photoluminescence quantum yield of 14.69% at the optimal In3+ alloying concentration. Simultaneously, the exciton lifetime was markedly extended 4.6 times, greatly enhancing carrier dynamics. Temperature-dependent photoluminescence spectroscopy analysis further confirms that postalloying with In3+, the NCs not only exhibit strong Coulombic forces and high thermal stability but also significantly reduce nonradiative transition processes. Moreover, density functional theory calculations reveal that In3+ alloying leads to a redistribution of charge density, profoundly affecting the electronic structure and subsequently enhancing the carrier mobility. Therefore, this study not only provides valuable insights into the role of In3+ alloying in enhancing the luminescence performance of double perovskite NCs but also opens up potential application prospects for optoelectronic devices in the future.
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
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Shengrong He,Jun Xing,Xiaorui Huang,Yue Sun,Xiaoman Ma,Ziyuan Huang,Bin Wang,Zhou Jiang,Ying Li,Longteng Wan,Jiahao Sun,Zhiyi Xu,Xiaolong Yao,Jiayong Zhang,Peng Li,Wei Li,Weili Yu
The 3D/2D perovskite film vertical heterojunction (3D/2D PFVH) has emerged as a promising candidate for high-performance photodetectors, as it overcomes the limitations of mono-perovskite while preserving their photoelectric properties and enhancing active layer stability, surface defect passivation, and carrier dynamics. However, controllable and cost-effective fabrication of efficient 3D/2D PFVH remains challenging. Herein, an improved hot-pressing reaction transfer-assisted method is proposed to successfully prepare high-quality 3D/2D PFVH after optimizing pressure and concentration. A carrier dynamics model is also proposed to elucidate the changes in defect states, carrier dynamics, and photophysical properties during the formation of 3D/2D PFVH. Furthermore, the efficient 3D/2D PFVH under optimal conditions exhibited remarkable enhancements in photoluminescence, carrier lifetime, humidity stability, and defect mitigation. Ultimately, the champion 3D/2D PFVH horizontal photodetector achieved a record-performance in photo-responsivity (R up to 4.59 A/W) and external quantum efficiency (EQE up to 1.07 × 10 3 %), signifying their superior light detection capabilities. This study offers valuable insights for designing high-quality 3D/2D PFVH for advanced high-performance planar optoelectronic devices for multiple scenes.
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
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