Interface Design for Metal Halide Perovskite Solar Cells

With the rise of thin-film photovoltaics, the research community brought the interfaces within the device into the spotlight for performance enhancements. This Perspective lays out why this notion is especially applicable for solar cells based on metal halide perovskite (MHP) absorber materials, for which we reach a significant improvement of device functionality and stability through the means of engineering the energetics and electronic properties at the interface. After examining recent key developments in chemical and electronic structure characterization of MHPs that led to this avenue, we will iterate the next steps toward interlayer tailoring and analysis. The future goal is to derive a comprehensive model for interface energetics in perovskite solar cells and to set up respective design rules for stable high-efficiency cells. This approach also pertains to the broader scope of MHP-based optoelectronic devices for which charge carrier transport across the interfaces and surface recombination play a major role.