Enhanced Hole Extraction of WOx/V2Ox Dopant-Free Contact for p-type Silicon Solar Cell

Nonstoichiometric vanadium oxide V 2 O x has been demonstrated to serve as a hole-selective contact in crystalline silicon solar cells. A reaction between V 2 O 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 V 2 O x as deposited on silicon and improving solar cell efficiency, avoiding the use of amorphous silicon. Incorporating WO x into the Ag/V 2 O x 1 /Si structure, to form Ag/WO x /V 2 O x 2 /Si, x 1 < x 2 , the WF determined by nonstoichiometric ratio, i.e., x , of V 2 O 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.