Enhanced Hole Extraction of WO_x/V₂O_x Dopant‐Free Contact for p‐type Silicon Solar Cell

Abstract Nonstoichiometric vanadium oxide V₂O_x has been demonstrated to serve as a hole‐selective contact in crystalline silicon solar cells. A reaction between V₂O_x deposited by thermal evaporation and silicon can, however, result in a decreased work function (WF) and reduce hole selectivity. A straightforward and workable solution is presented in this study, which partially restores the WF of V₂O_x as deposited on silicon and improving solar cell efficiency, avoiding the use of amorphous silicon. Incorporating WO_x into the Ag/V₂O_x1/Si structure, to form Ag/WO_x/V₂O_x2/Si, x₁<x₂, the WF determined by nonstoichiometric ratio, i.e., x, of V₂O_x increases, enhancing the field passivation effect and reducing the rear recombination, which leads to a 11 mV increase in open‐circuit voltage and a 0.90 mA cm⁻² increase in short‐circuit current. Finally, the solar cell gains an absolute improvement of ≈1.0% in power conversion efficiency.