An 8.7% efficiency co-electrodeposited Cu ₂ ZnSnS ₄ photovoltaic device fabricated via a pressurized post-sulfurization process

Cu ₂ ZnSnS ₄ (CZTS) photovoltaic devices with Cu-Zn-Sn-S precursors were prepared by co-electrodeposition. This is a low-cost, environmentally favorable and non-vacuum process with broad industrial prospects. However, due to the relatively narrow range of phase forming conditions and insufficient sulfurization, it is difficult to obtain fine control over the composition of CZTS films with pure phase structures and uniform grain size distributions. In this work, co-electrodeposited Cu-Zn-Sn-S precursors were sulfurized in an atmosphere of sulfur (S) and nitrogen gas (N ₂ ). The S contents in the CZTS films were controlled by varying the N ₂ gas pressure. After optimization, we obtained a maximum efficiency of 8.7%, which is the highest reported for co-electrodeposited CZTS devices to date.