Potentiostatic Photoluminescence Imaging of Charge Extraction in Perovskite Solar Cells

We propose a novel approach for microscopically resolved photocurrent imaging. The method is based on the notion that electrical bias-dependent photoluminescence images reveal fundamental information on charge extraction of photovoltaic devices. The approach is derived from basic physical principles and verified by means of a near-to-ideal III-V solar cell. It is demonstrated that the approach is of special relevance for liquid-processed perovskite solar cells. We outline the potential to investigate the local charge extraction efficiency, which can be related to fundamental charge extraction properties associated with the quality of interfaces and morphological defects from device processing. The method demonstrates that photoluminescence imaging can be a powerful tool for device optimization as well as fundamental studies when carried out at different bias voltages.