Ultraviolet irradiation-induced improvement of silicon heterojunction solar cells via zinc-doped indium oxide with low ultraviolet transmittance

The application of silicon heterojunction (HJT) solar cells in space environments faces a critical challenge from ultraviolet-induced degradation (UVID). In this work, high-quality zinc doped indium oxide (IZO) films with narrow bandgap were prepared by reactive plasma deposition (RPD). UV irradiation can cause the breakage of some Zn-O bonds, facilitating the formation of oxygen vacancies. This enhances the electrical conductivity of IZO and reduces work function, thereby improving energy level alignment with the n-type doped layer and promoting electron transport. HJT solar cells with IZO exhibited excellent resistance to UV irradiation. After exposure to 3000 equivalent sun hours (ESH) of UV irradiation, the IZO cells demonstrated a remarkable 4.0% increase in power conversion efficiency (PCE), driven by an 8.4% improvement in fill factor (FF). These findings establish IZO as a promising UV-resistant transparent conductive oxide for high-stability HJT solar cells in low earth orbit space applications.