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Vol. 9 No. 2 (2017)

Improving the Performance of PbS Quantum Dot Solar Cells by Optimizing ZnO Window Layer

https://doi.org/10.1007/s40820-016-0124-2
Xiaokun Yang
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Long Hu
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Hui Deng
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Keke Qiao
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Chao Hu
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Zhiyong Liu
State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Shengjie Yuan
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Jahangeer Khan
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Dengbing Li
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Jiang Tang
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Haisheng Song
Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
Chun Cheng
Department of Materials Science and Engineering and Shenzhen Key Laboratory of Nanoimprint Technology, South University of Science and Technology, Shenzhen 518055, People’s Republic of China

Corresponding Author: Chun Cheng

chengc@sustc.edu.cn

Nano-Micro Letters, Vol. 9 No. 2 (2017), Article Number: 24

Abstract

Comparing with hot researches in absorber layer, window layer has attracted less attention in PbS quantum dot solar cells (QD SCs). Actually, the window layer plays a key role in exciton separation, charge drifting, and so on. Herein, ZnO window layer was systematically investigated for its roles in QD SCs performance. The physical mechanism of improved performance was also explored. It was found that the optimized ZnO films with appropriate thickness and doping concentration can balance the optical and electrical properties, and its energy band align well with the absorber layer for efficient charge extraction. Further characterizations demonstrated that the window layer optimization can help to reduce the surface defects, improve the heterojunction quality, as well as extend the depletion width. Compared with the control devices, the optimized devices have obtained an efficiency of 6.7% with an enhanced V oc of 18%, J sc of 21%, FF of 10%, and power conversion efficiency of 58%. The present work suggests a useful strategy to improve the device performance by optimizing the window layer besides the absorber layer.


Highlights:


1 The efficiencies of PbS solar cells was significantly improved from 4.3% to 6.7% by optimizing ZnO window layer.
2 Optimized ZnO window layer can reduce the surface defects, extend thedepleted-heterojunction width and align with energy band of absorber layer.

Keywords

ZnO Window layer Thin film solar cells PbS quantum dots Physical mechanism
Yang, Xiaokun, Long Hu, Hui Deng, Keke Qiao, Chao Hu, Zhiyong Liu, Shengjie Yuan, Jahangeer Khan, Dengbing Li, Jiang Tang, Haisheng Song, and Chun Cheng. 2017. “Improving the Performance of PbS Quantum Dot Solar Cells by Optimizing ZnO Window Layer”. Nano-Micro Letters 9 (2):24. https://doi.org/10.1007/s40820-016-0124-2.
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