Drift-diffusion modeling of perovskite solar cells: A systematic approach

Perovskites are one of the most promising materials for the next generation of solar cells. They have high absorption coefficients, tunable bandgaps, and are versatile. However, there are still challenges regarding performance and resolving issues such as stability and degradation. To solve these challenges, a deep understanding of the inner workings of these devices is essential. Using numerical drift-diffusion simulations in combination with experimental data is an excellent approach to tackle this. However, doing this in an effective and careful way requires a rigid and thorough approach. Here, we define and demonstrate a systematic and elaborate approach for drift-diffusion modeling of perovskite solar cells (PSCs), taking into account the accuracy and repeatability of the experimental data. The approach goes beyond obtaining just a good fit with a single set of parameters but rather a unique scenario that addresses the reliability and interpretability of the obtained results. We demonstrate the effectiveness of a systematic approach by applying it to a state-of-the-art PSC, where, upon adding various amounts of chloride during the perovskite evaporation, a large change in open-circuit voltage was observed. We show that using drift-diffusion simulations, this can be explained by an increased energy step between the conduction bands of the perovskite and the electron transport layer upon increased chloride addition. When following this systematic approach, drift-diffusion modeling becomes a very powerful tool to push the limits of efficiency for PSCs.