Reducing the formation of Sb2O3 phase and selenium vacancy in Sb2Se3 thin film solar cells via hydrogen-assisted selenization

In this study, we investigated the influence of Sb2O3 or selenium vacancies (V-se) on the characteristics of Sb2Se3 films, and developed a novel hydrogen-assisted selenization (HAS) scheme aimed at reducing the formation of Sb2O3 and V-se in the absorber layer of Sb2Se3 solar cells. In experiments, subsurface Sb2O3 formation was more pronounced in RF samples than in DC samples. An Sb2Se3 absorber prepared using RF sputtering without HAS converted from p-type conductivity to n-type conductivity, which reduced the J(SC) values and device efficiency. Furthermore, the Sb2O3 phase that formed on the surface of the Sb2Se3 film acted as a channel for current flow, which greatly increased current leakage at p-n junction interfaces. Our results indicate that the formation of Sb2O3 phase can lead to a Se-poor state, resulting in the formation of V-Se defects in the Sb2Se3 absorber layer, with a corresponding decrease in Jsc. The HAS process was shown to reduce the formation of Sb2O3 and Vse in the Sb2Se3 absorber, resulting in device efficiency of 6.16% and Jsc of 27.57 mA/cm(2), the highest ever recorded for Sb2Se3 thin film solar cells prepared via sputtering.