Reduced recombination through CZTS/CdS interface engineering in monograin layer solar cells

Abstract The power conversion efficiency of Cu 2 ZnSnS 4 (CZTS) solar cells is still limited by deep defects, low minority carrier lifetime and high recombination rates at the CZTS/CdS interface. objective this study was to find an effective method reduce interface CZTS monograin layer cells. A two-step heterojunction formation process applied controlling intermixing Cd in interface, which resulted improved device up 11.7%. Surface analysis x-ray photoelectron spectroscopy confirmed diffusion into surface after CdS air-annealing forming ultra-thin Zn x 1− SnS layer. Moreover, external quantum measurements showed that absorption edge shifts longer wavelengths with addition This modification replacement a CdS:Cu buffer fresh greatly reduced junction quality, contributing enhancement J SC ∼3 mA cm −2 (from 20.5 23.6 ) fill factor ∼14% 59.4% 67.7%). serial resistance significantly from 2.4 Ω 0.67 . To understand electrical behavior highest-efficiency cell more detail, temperature-dependent current–voltage characteristics were analyzed.