13% Efficiency Hybrid Organic/Silicon-Nanowire Heterojunction Solar Cell via Interface Engineering

• Published in: ACS nano Vol. 7; no. 12; pp. 10780 - 10787
• Main Authors: Yu, Peichen, Tsai, Chia-Ying, Chang, Jan-Kai, Lai, Chih-Chung, Chen, Po-Han, Lai, Yi-Chun, Tsai, Pei-Ting, Li, Ming-Chin, Pan, Huai-Te, Huang, Yang-Yue, Wu, Chih-I, Chueh, Yu-Lun, Chen, Shih-Wei, Du, Chen-Hsun, Horng, Sheng-Fu, Meng, Hsin-Fei
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 23.12.2013
• Subjects: Devices; Electric potential; Heterojunctions; Insertion; Minority carriers; Nanowires; Photovoltaic cells; Silicon; Solar cells; small molecule; hybrid solar cell; conductive polymer; interface engineering
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/nn403982b

Interface carrier recombination currently hinders the performance of hybrid organic–silicon heterojunction solar cells for high-efficiency low-cost photovoltaics. Here, we introduce an intermediate 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) layer into hybrid heterojunction solar cells based on silicon nanowires (SiNWs) and conjugate polymer poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS). The highest power conversion efficiency reaches a record 13.01%, which is largely ascribed to the modified organic surface morphology and suppressed saturation current that boost the open-circuit voltage and fill factor. We show that the insertion of TAPC increases the minority carrier lifetime because of an energy offset at the heterojunction interface. Furthermore, X-ray photoemission spectroscopy reveals that TAPC can effectively block the strong oxidation reaction occurring between PEDOT:PSS and silicon, which improves the device characteristics and assurances for reliability. These learnings point toward future directions for versatile interface engineering techniques for the attainment of highly efficient hybrid photovoltaics.