Core–Shell Heterojunction of Silicon Nanowire Arrays and Carbon Quantum Dots for Photovoltaic Devices and Self-Driven Photodetectors

• Published in: ACS nano Vol. 8; no. 4; pp. 4015 - 4022
• Main Authors: Xie, Chao, Nie, Biao, Zeng, Longhui, Liang, Feng-Xia, Wang, Ming-Zheng, Luo, Linbao, Feng, Mei, Yu, Yongqiang, Wu, Chun-Yan, Wu, Yucheng, Yu, Shu-Hong
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 22.04.2014
• Subjects: Arrays; Carbon; Heterojunctions; Nanostructure; Nanowires; Photodetectors; Photovoltaic cells; Qunatum dots; Silicon; Solar cells; relative balance; surface passivation; barrier height; silicon nanowire array; carbon quantum dots
• ISSN: 1936-0851; 1936-086X; 1936-086X
• DOI: 10.1021/nn501001j

Silicon nanostructure-based solar cells have lately intrigued intensive interest because of their promising potential in next-generation solar energy conversion devices. Herein, we report a silicon nanowire (SiNW) array/carbon quantum dot (CQD) core–shell heterojunction photovoltaic device by directly coating Ag-assisted chemical-etched SiNW arrays with CQDs. The heterojunction with a barrier height of 0.75 eV exhibited excellent rectifying behavior with a rectification ratio of 103 at ±0.8 V in the dark and power conversion efficiency (PCE) as high as 9.10% under AM 1.5G irradiation. It is believed that such a high PCE comes from the improved optical absorption as well as the optimized carrier transfer and collection capability. Furthermore, the heterojunction could function as a high-performance self-driven visible light photodetector operating in a wide switching wavelength with good stability, high sensitivity, and fast response speed. It is expected that the present SiNW array/CQD core–shell heterojunction device could find potential applications in future high-performance optoelectronic devices.