Procedure Based on External Quantum Efficiency for Reliable Characterization of Perovskite Solar Cells

Perovskite solar cells (PSCs) have the potential for widespread application, but challenges remain for a reliable characterization of their performance. Standardized protocols for measuring and reporting are still debated. Focusing on the short circuit current density ( J SC ), current–voltage characteristics ( J–V ) and external quantum efficiency (EQE) are collected to estimate the parameter. Still, they often provide a mismatch above 1 mA cm −2 , resulting in a possible 5% or higher error. Combining experimental data and optical simulations, it is demonstrated that the EQE can provide a reliable estimate of the J SC that could otherwise easily be overestimated by J–V . With access to the internally transmitted light through simulations, an upper limit for EQE is defined depending on the front layers. Details on the origin of the spectral shape and contributions to the optical losses are obtained with further optical simulations, providing hints for cell optimization to achieve a photocurrent gain. The authors use solution‐processed n‐i‐p PSCs with triple‐cation mixed‐halide absorbers as demonstrators and ultimately come to the proposal of an upgrade of the present best practices in PSC efficiency measurements. Still, the approach and conclusions are general and apply to cells with all designs and chemical formulations.