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134 results on '"Zeng, Qingsen"'

8. Solvent-Reconstructed Interface That Enhances Light Out-Coupling in Quasi-Two-Dimensional Perovskite Light-Emitting Diodes

Author

Yang, Fan, Dong, Wei, Kang, Chunyuan, Zhu, Zhicheng, Zeng, Qingsen, Zheng, Weitao, Zhang, Xiaoyu, and Yang, Bai

Abstract

Light management is critical to maximizing the external quantum efficiency of perovskite light-emitting diodes (PeLEDs), but strategies for enhancing light out-coupling are typically complex and expensive. Here, using a facile solvent treatment strategy, we create a layer of lithium fluoride (LiF) nanoislands that serve as a template to reconstruct the light-extracting interfaces for PeLEDs. The nanoisland interface rearranges the near-field light distribution in order to maximize the efficiency of internal light extraction. With the proper adjustment of the nanoisland size and distribution, we have achieved an optimal balance between charge injection and light out-coupling, resulting in bright, pure-red quasi-two-dimensional PeLEDs with a 21.8% peak external quantum efficiency.

Published
2024
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13. Amine-Terminated Carbon Dots Linking Hole Transport Layer and Vertically Oriented Quasi-2D Perovskites through Hydrogen Bonds Enable Efficient LEDs

Author

Dong, Wei, primary, Zhang, Xiaoyu, additional, Yang, Fan, additional, Zeng, Qingsen, additional, Yin, Wenxu, additional, Zhang, Wei, additional, Wang, Haoran, additional, Yang, Xuyong, additional, Kershaw, Stephen V., additional, Yang, Bai, additional, Rogach, Andrey L., additional, and Zheng, Weitao, additional

Published
2022
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23. A highly efficient overall water splitting ruthenium-cobalt alloy electrocatalyst across a wide pH range via electronic coupling with carbon dots

Author

Feng, Tanglue, primary, Yu, Guangtao, additional, Tao, Songyuan, additional, Zhu, Shoujun, additional, Ku, Ruiqi, additional, Zhang, Ran, additional, Zeng, Qingsen, additional, Yang, Mingxi, additional, Chen, Yixin, additional, Chen, Weihua, additional, Chen, Wei, additional, and Yang, Bai, additional

Published
2020
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24. Enhanced charge separation and photocatalytic hydrogen evolution in carbonized-polymer-dot-coupled lead halide perovskites

Author

Zhao, Yue, primary, Zeng, Qingsen, additional, Yu, Yue, additional, Feng, Tanglue, additional, Zhao, Yajie, additional, Wang, Zidong, additional, Li, Yi, additional, Liu, Chongming, additional, Liu, Junjun, additional, Wei, Haotong, additional, Zhu, Shoujun, additional, Kang, Zhenhui, additional, Zhang, Hao, additional, and Yang, Bai, additional

Published
2020
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25. Polymer-Passivated Inorganic Cesium Lead Mixed-Halide Perovskites for Stable and Efficient Solar Cells with High Open-Circuit Voltage over 1.3 V

Author

Zeng, Qingsen, Zhang, Xiaoyu, Feng, Xiaolei, Lu, Siyu, Chen, Zhaolai, Yong, Xue, Redfern, Simon AT, Wei, Haotong, Wang, Haiyu, Shen, Huaizhong, Zhang, Wei, Zheng, Weitao, Zhang, Hao, Tse, John S, Yang, Bai, Feng, Xiaolei [0000-0003-4410-4576], Redfern, Simon [0000-0001-9513-0147], and Apollo - University of Cambridge Repository

Subjects
nanocrystals, inorganic perovskites, energy loss, solar cells, defect states, energy disorder, surface passivation, polymers
Abstract

Cesium-based trihalide perovskites have been demonstrated as promising light absorbers for photovoltaic applications due to their superb composition stability. However, the large energy losses (Eloss ) observed in inorganic perovskite solar cells has become a major hindrance impairing the ultimate efficiency. Here, an effective and reproducible method of modifying the interface between a CsPbI2 Br absorber and polythiophene hole-acceptor to minimize the Eloss is reported. It is demonstrated that polythiophene, deposited on the top of CsPbI2 Br, can significantly reduce electron-hole recombination within the perovskite, which is due to the electronic passivation of surface defect states. In addition, the interfacial properties are improved by a simple annealing process, leading to significantly reduced energy disorder in polythiophene and enhanced hole-injection into the hole-acceptor. Consequently, one of the highest power conversion efficiency (PCE) of 12.02% from a reverse scan in inorganic mixed-halide perovskite solar cells is obtained. Modifying the perovskite films with annealing polythiophene enables an open-circuit voltage (VOC ) of up to 1.32 V and Eloss of down to 0.5 eV, which both are the optimal values reported among cesium-lead mixed-halide perovskite solar cells to date. This method provides a new route to further improve the efficiency of perovskite solar cells by minimizing the Eloss .

Published
2018
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30. Surface Ligands Management for Efficient CsPbBrI2 Perovskite Nanocrystal Solar Cells.

Author

Liu, Chongming, Zeng, Qingsen, Zhao, Yue, Yu, Yue, Yang, Mingxi, Gao, Hang, Wei, Haotong, and Yang, Bai

Subjects
SOLAR cells, SEMICONDUCTOR nanocrystals, OPTOELECTRONIC devices, BULK solids, NUCLEAR magnetic resonance, ETHYL acetate
Abstract

CsPbX3 (X = Cl, Br, I) inorganic perovskite nanocrystals (PNCs) not only maintain the excellent optical and electronic properties of bulk material but also possess the features of nano‐materials, such as tunable bandgap and easily processable colloidal ink, and enable them to be suitable for incorporation into various electronic devices and compatible with printing techniques. In contrast to the traditional II‐VI and III‐V semiconductor nanocrystals, the unique defect‐tolerance effect makes the CsPbX3 PNCs promising materials for optoelectronic applications. The ligands around the PNCs play a critical role in the optoelectronic devices performance. Herein, through a facile hexane/ethyl acetate (MeOAc) solvent treatment method to control the ligand amount around CsPbBrI2 PNCs, the impact of ligand amount on the performance of solar cell is systematically demonstrated and the ligand amount is quantified precisely via the nuclear magnetic resonance internal standard method. Through controlling the ligand amount, the film quality, charge transfer, and transport properties are largely improved. In addition, a simple annealing process is applied to improve the interface properties by partial crystal fusion. As a consequence, the photovoltaic power conversion efficiency of 12.2% is achieved, which is the highest performance reported for mixed‐halide CsPbX3 PNCs solar cells. [ABSTRACT FROM AUTHOR]

Published
2020
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31. Preparation of textured and transparent BiVO4 photoelectrodes based on Mo-doped BiVO4 nanoparticles for constructing a stand-alone tandem water splitting device.

Author

Wang, Ze, Dong, Chunwei, Liang, Sen, Yao, Shiyu, Wang, Zidong, Zeng, Qingsen, Liu, Chongming, Liu, Yi, Yang, Bai, and Zhang, Hao

Subjects
WATER efficiency, SILICON solar cells, NANOPARTICLES, SOLAR cells, OXIDATION of water
Abstract

Crystallographic orientation control is an effective method to improve the photoelectrochemical water splitting efficiency of BiVO4 photoanodes. Herein, textured and transparent Mo–BiVO4 photoanodes are fabricated by spin-coating Mo-doped BiVO4 nanoparticles on FTO. The photoelectrodes exhibit a current density of 4.15 mA cm−2 and 2.50 mA cm−2 for sulfite and water oxidation, respectively. By connecting the photoelectrode with a CsPbBrI2 perovskite solar cell, a stand-alone tandem water splitting device with a current density of 2.13 mA cm−2 and an STH of 2.43% can be achieved. [ABSTRACT FROM AUTHOR]

Published
2020
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32. Energy Level Modification with Carbon Dot Interlayers Enables Efficient Perovskite Solar Cells and Quantum Dot Based Light‐Emitting Diodes.

Author

Zhang, Xiaoyu, Zeng, Qingsen, Xiong, Yuan, Ji, Tianjiao, Wang, Chen, Shen, Xinyu, Lu, Min, Wang, Haoran, Wen, Shanpeng, Zhang, Yu, Yang, Xuyong, Ge, Xin, Zhang, Wei, Litvin, Aleksandr P., Baranov, Alexander V., Yao, Dong, Zhang, Hao, Yang, Bai, Rogach, Andrey L., and Zheng, Weitao

Subjects
*SOLAR cells, *SILICON solar cells, *QUANTUM dots, *DIODES, *QUANTUM dot LEDs, *OPTOELECTRONIC devices, *ZINC sulfide, *LEAD sulfide
Abstract

Controlling the transport and minimizing charge carrier trapping at interfaces is crucial for the performance of various optoelectronic devices. Here, how electronic properties of stable, abundant, and easy‐to‐synthesized carbon dots (CDs) are controlled via the surface chemistry through a chosen ratio of their precursors citric acid and ethylenediamine are demonstrated. This allows to adjust the work function of indium tin oxide (ITO) films over the broad range of 1.57 eV, through deposition of thin CD layers. CD modifiers with abundant amine groups reduce the ITO work function from 4.64 to 3.42 eV, while those with abundant carboxyl groups increase it to 4.99 eV. Using CDs to modify interfaces between metal oxide (SnO2 and ZnO) films and active layers of solar cells and light‐emitting diodes (LEDs) allows to significantly improve their performance. Power conversion efficiency of CH3NH3PbI3 perovskite solar cells increases from 17.3% to 19.5%; the external quantum efficiency of CsPbI3 perovskite quantum dot LEDs increases from 4.8% to 10.3%; and that of CdSe/ZnS quantum dot LEDs increases from 8.1% to 21.9%. As CD films are easily fabricated in air by solution processing, the approach paves the way to a simplified manufacturing of large‐area and low‐cost optoelectronic devices. [ABSTRACT FROM AUTHOR]

Published
2020
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35. Polymer‐Passivated Inorganic Cesium Lead Mixed‐Halide Perovskites for Stable and Efficient Solar Cells with High Open‐Circuit Voltage over 1.3 V

Author

Zeng, Qingsen, primary, Zhang, Xiaoyu, additional, Feng, Xiaolei, additional, Lu, Siyu, additional, Chen, Zhaolai, additional, Yong, Xue, additional, Redfern, Simon A. T., additional, Wei, Haotong, additional, Wang, Haiyu, additional, Shen, Huaizhong, additional, Zhang, Wei, additional, Zheng, Weitao, additional, Zhang, Hao, additional, Tse, John S., additional, and Yang, Bai, additional

Published
2018
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37. Polymer-Passivated Inorganic Cesium Lead Halide Perovskites for High-Voltage and High-Efficiency Solar Cells

Author

Zeng, Qingsen, primary, Zhang, Xiaoyu, additional, Feng, Xiaolei, additional, Lu, Siyu, additional, Chen, Zhaolai, additional, Yong, Xue, additional, Redfern, Simon A. T., additional, Wei, Haotong, additional, Wang, Haiyu, additional, Shen, Huaizhong, additional, Zhang, Wei, additional, Zheng, Weitao, additional, Zhang, Hao, additional, Tse, John S., additional, and Yang, Bai, additional

Published
2018
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38. Aqueous-Processed Polymer/Nanocrystal Hybrid Solar Cells with Double-Side Bulk Heterojunction

Author

Jin, Gan, primary, Chen, Nannan, additional, Zeng, Qingsen, additional, Liu, Fangyuan, additional, Yuan, Wei, additional, Xiang, Siyuan, additional, Feng, Tanglue, additional, Du, Xiaohang, additional, Ji, Tianjiao, additional, Wang, Lijing, additional, Wang, Yaohua, additional, Sun, Henan, additional, Sun, Haizhu, additional, and Yang, Bai, additional

Published
2017
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44. Aqueous-Processed Polymer/Nanocrystals Hybrid Solar Cells: The Effects of Chlorine on the Synthesis of CdTe Nanocrystals, Crystal Growth, Defect Passivation, Photocarrier Dynamics, and Device Performance

Author

Zeng, Qingsen, primary, Chen, Zhaolai, additional, Liu, Fangyuan, additional, Jin, Gan, additional, Du, Xiaohang, additional, Ji, Tianjiao, additional, Zhao, Yue, additional, Yue, Yuanyuan, additional, Wang, Haiyu, additional, Meng, Dedong, additional, Xie, Tengfeng, additional, Zhang, Hao, additional, and Yang, Bai, additional

Published
2017
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46. Enhanced charge separation and photocatalytic hydrogen evolution in carbonized-polymer-dot-coupled lead halide perovskitesElectronic supplementary information (ESI) available. See DOI: 10.1039/d0mh00955e

Author

ZhaoY. Z., Yue, work., Q. Z. contributed equally to this, Zeng, Qingsen, Yu, Yue, Feng, Tanglue, Zhao, Yajie, Wang, Zidong, Li, Yi, Liu, Chongming, Liu, Junjun, Wei, Haotong, Zhu, Shoujun, Kang, Zhenhui, Zhang, Hao, and Yang, Bai

Abstract

Metal halide perovskites are promising candidates as photocatalysts due to their uniquely outstanding photophysical properties; however, the catalytic efficiency is limited by severe charge recombination. Herein, we show that carbonized polymer dots (CPDs) can act as an efficient charge modulator to stabilize photo-generated carriers in methylamine lead triiodide (MAPbI3) perovskites through ultra-fast hole transfer, and thus increase the rate of visible light-driven photocatalytic HI splitting 35-fold. The optimized CPD/MAPbI3/Pt hybrid photocatalytic system exhibits an impressive H2evolution rate of 11 497 μmol h−1g−1, a solar-to-hydrogen conversion efficiency of 2.15%, and an apparent quantum yield of 53.6% at 420 nm, which are among the highest values for metal halide perovskite photocatalysts. Moreover, the presented strategy of hole extraction viaCPDs can be universally applied to improve the performance of previous electron-manipulated MAPbI3-based photocatalytic systems. The easy-to-prepare and bandedge-tunable CPDs with excellent charge-transfer ability may bring new insights in developing high-performance perovskite photocatalysts.

Published
2020
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