Improving the photovoltaic effect by resistive switching

Abstract

The mismatch between band structures of a light-absorptive layer and hole or electron transport layers will significantly deteriorate the performance of photovoltaic devices, which is generally alleviated by inserting a mitigating layer. In this report, we propose an alternative strategy to improve the efficiency by using resistive switching, which may decrease defect density in bulk and the lower barrier height at the interface due to the migration of defects to the interface under a certain electric field. By using a BiFeO3 film as a model light harvesting layer, a TiO2 mesoporous layer as an electron transport layer, and NiOx as a hole transport layer, bipolar resistive switching behavior has been observed. By setting the device in the low resistance state under certain applied voltages, performance has been significantly improved. Compared with the virgin device, the highest short-circuit current Jsc increases 2.3 times from 2.38 to 5.66 μA cm−2 and open-circuit voltage Voc increases 1.35 times from 0.39 to 0.525 V.