Enhancement of photocurrent in Cu2ZnSnS4 quantum dot-anchored multi-walled carbon nanotube for solar cell application

Abstract

Photoconductivity of kesterite CZTS (Cu2ZnSnS4) quantum dots (QDs) anchored on multi-walled carbon nanotubes (MWCNTs) hybrid nanostructures has been investigated here, which take the advantages of both CZTS QDs and MWCNTs. The objective material CZTS QDs-anchored MWCNTs hybrid nanostructure have been prepared by a simple solution casting approach without doing any surface modifications. As-prepared MWCNTs, CZTS QDs and CZTS QDs–MWCNTs hybrid nanostructure have been characterized by XRD, Raman, FTIR, XPS, FESEM and TEM, and UV–visible spectroscopy. The improved optical gain of CZTS QDs–MWCNTs has been observed by UV–visible spectroscopy analysis. Other characterizations and TEM micrographs confirmed the adherence of CZTS QDs on MWCNTs. The photoconductivity of the above prepared hybrid nanostructure has been measured both in dark and under illumination (1.5G solar simulator). The hybrid nanostructure demonstrated improved photocurrent compared to bare CZTS QDs and MWCNTs. The obtained improved photocurrent is due to high optical gain by CZTS QDs and fast charge carrier transport by MWCNTs throughout in the hybrid nanostructure. The enhanced photocurrent and the stability of the CZTS–MWCNTs hybrid nanostructure ensure a possible application in future solar cell.