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

Nonstoichiometric vanadium oxide V2Ox has been demonstrated to serve as a hole-selective contact in crystalline silicon solar cells. A reaction between V2Ox 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 V2Ox as deposited on silicon and improving solar cell efficiency, avoiding the use of amorphous silicon. Incorporating WOx into the Ag/V2Ox1/Si structure, to form Ag/WOx/V2Ox2/Si, x(1)<x(2), the WF determined by nonstoichiometric ratio, i.e., x, of V2Ox 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 approximate to 1.0% in power conversion efficiency.