Spectroscopic Analysis for the Identification of Loss Mechanisms in Back‐Contact Perovskite Solar Cells

Abstract Back‐contact perovskite solar cells offer a significant potential to reach high efficiency due to reduced parasitic absorption from the top surface. However, the currently reported efficiencies are considerably lower (<10%) than planar perovskite solar cells (>20%). Herein, back‐contact perovskite solar cells are fabricated to study loss mechanisms that cause low device efficiency. This work spatially resolves the short‐circuit current, open‐circuit voltage, photoluminescence quantum yield, carrier lifetime, and external quantum efficiency of the devices. The results indicate that the front surface recombination, increased nonradiative recombination at hole contact layer/perovskite interface, and the extraction barriers are three main mechanisms limiting devices from achieving high efficiencies.