Spectroscopic analysis for the identification of loss mechanisms in back‐contact perovskite solar cells

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.