Ultra‐Thin Perovskite Solar Cells Analytical Model Involving Radiative and Nonradiative Carrier Recombination Mechanisms

Abstract

Understanding the reasons for the high efficiencies and open‐circuit voltages of perovskite solar cells is fundamental for achieving performance improvements in the future. Therefore, herein, a perovskite cell model is developed in which both radiative and nonradiative recombination currents are included by two diode equations with ideality factors of 1 and 2, respectively, and then the conversion efficiency dependence on carrier lifetime, perovskite material bandgap, and device thickness is studied, considering these two recombination mechanisms. The capability of the model for the evaluation and prediction of performances of perovskite solar cells is also shown, agreeing very well with current experimental efficiencies for these cells. It avoids complicated numerical solutions for the transport equations and makes use of well‐known analytical expressions for developing a real novel model. This model allows the estimation of the optimum perovskite thickness, and it also helps in determining what should be the required device carrier lifetimes for having increased efficiencies, above the current 23.7% record. It is predicted that (nonradiative) lifetimes larger than 10 μs in the perovskite cell material will not cause any efficiency improvement above the expected limit of 29%. The model agrees well with reported experimental results.