Tunneling-enhanced interface recombination and current loss curves in kesterite solar cells

Abstract

An approach to developing durable, light-weight, flexible, and semi-transparent solar cells is through the utilization of Cu2ZnSnS4 (CZTS) monograin powder. However, CZTS cells are currently far from their theoretically predicted efficiency. One reason for this is tunneling-enhanced interface recombination, which leads to a decrease in VOC and FF under higher forward bias conditions. We calculated the current loss curves JR–V of three different CZTS monograin layer solar cells for this report by subtracting the dark J–V curve from the light curve and adding a short circuit current density JSC. By quantum tunneling of holes through a bell-shaped potential barrier with additional recombination at the interface between CdS and CZTS, the shape of the current loss curve was examined. We showed that using the derivative dJR/dV of the measured curves allows us to simplify our analysis. The maximum position of this curve is proportional to the effective barrier height, and the intensity and the full width at half maximum give information about the width. At lower temperatures, the effective barrier height increases according to our theoretical model. We demonstrated that the properties of CZTS solar cells may be significantly enhanced by eliminating current loss at higher bias voltages.