Solution Processed Organic/Silicon Nanowires Hybrid Heterojunction Solar Cells Using Organosilane Incorporated Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) as Hole Transport Layers

Abstract

Hybrid heterojunction solar cells (HHSCs) using crystalline Si nanowires (SiNWs) as the absorber and conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the hole-selective transport layer (HTL) show great potential in both low-cost and high-power conversion efficiency (PCE). However, due to the poor wettability of the PEDOT:PSS solution on SiNWs, conformal coverage of PEDOT:PSS on SiNWs is not easy to achieve. Here, an effective method was developed to decrease the surface tension of the PEDOT:PSS and increase the wettability between PEDOT:PSS and SiNWs by incorporating organosilane into the PEDOT:PSS solution. Two kinds of organosilanes including tetramethoxysilane (TMOS) and vinyltrimethoxysilane (VTMO) were selected as the additives. The surface passivation quality of the SiNWs was dramatically enhanced. The HHSCs utilizing VTMO as the additive show a higher open circuit voltage and higher PCE compared with the TMOS adding ones. By spin-coating Ag nanowires onto the PEDOT:PSS HTL layer and using spin-coated phenyl-C61-butyric acid methyl ester as the electron-selective transport layer, a champion PCE up to 18.12% and a fill factor of 80.1% have been achieved on the full solution processed PEDOT:PSS/n-type SiNWs HHSCs. The findings provide a simple and promising method to achieve high-performance PEDOT:PSS/SiNWs HHSCs.