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

• DOI: 10.1021/nn403982b
• Publication Date: 2013-11-13T22:48:59Z
• Authors: Peichen Yu; Chia-Ying Tsai; Jan-Kai Chang; Chih-Chung Lai; Po-Han Chen; Yi-Chun Lai; Pei-Ting Tsai; Ming-Chin Li; Huai-Te Pan; Yang-Yue Huang; Chih-I Wu; Yu-Lun Chueh; Shih-Wei Chen; Chen-Hsun Du; Sheng-Fu Horng; Hsin-Fei Meng
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

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.