SOCl2 enhanced photovoltaic conversion of single wall carbon nanotube/ n -silicon heterojunctions

Abstract

We report solar cells based on high-density p-n heterojunctions between single wall carbon nanotubes (SWCNTs) and a n -type silicon wafer. Chemical modification by thionyl chloride of the SWCNT coating films was found to significantly increase the conversion efficiency by more than 45% through adjusting the Fermi level and increasing the carrier concentration and mobility. Electron-hole pairs are optically excited in the numerous heterojunctions formed between SOCl2 -treated SWCNTs thin coating and n -type silicon substrate, and then split and transported through SWCNTs (holes) and n-Si (electrons), respectively. © 2008 American Institute of Physics.