Engineering the Interfaces of ITO@Cu2S Nanowire Arrays toward Efficient and Stable Counter Electrodes for Quantum-Dot-Sensitized Solar Cells

• Published in: ACS applied materials & interfaces Vol. 6; no. 17; pp. 15448 - 15455
• Main Authors: Jiang, Yan, Zhang, Xing, Ge, Qian-Qing, Yu, Bin-Bin, Zou, Yu-Gang, Jiang, Wen-Jie, Hu, Jin-Song, Song, Wei-Guo, Wan, Li-Jun
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10.09.2014
• Subjects: active sites; catalytic activity; cation exchange; copper; electrodes; electrolytes; nanocrystals; nanowires; photovoltaic cells; uncertainty; quantum dots; counter electrodes; solar cells; interface; nanowires
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/am504057y

Among the issues that restrict the power conversion efficiency (PCE) of quantum-dot-sensitized solar cells (QDSSCs), insufficient catalytic activity and stability of counter electrodes (CEs) are critical but challenging ones. The state-of-the-art Cu/Cu2S CEs still suffer from mechanical instability and uncertainty due to the reaction of copper and electrolyte. Herein, ITO@Cu2S core–shell nanowire arrays were developed to fabricate CEs for QDSSCs, which have no such issues in Cu/Cu2S CEs. These nanowire arrays exhibited small charge transfer resistance and sheet resistance, and provided more active catalytic sites and easy accessibility for electrolyte due to the three-dimensional structure upon use as CEs. More interestingly, it was found that the interface of ITO/Cu2S significantly affected the performance of ITO@Cu2S nanowire array CEs. By varying synthetic methods, a series of ITO@Cu2S nanowire arrays were prepared to investigate the influence of ITO/Cu2S interface on their performance. The results showed that ITO@Cu2S nanowire array CEs with a continuous Cu2S nanocrystal shell fabricated via an improved cation exchange route exhibited excellent and thickness-dependent performance. The PCE of corresponding QDSSCs increased by 11.6 and 16.5% compared to that with the discrete Cu2S nanocrystal and the classic Cu/Cu2S CE, respectively, indicating its promising potential as a new type of CE for QDSSCs.