Pressure Effects on Lead-Free Metal Halide Perovskites: a Route to Design Optimized Materials for Photovoltaics

Metal halide perovskites have drawn significant attention for their promising physical properties and their possible application in solar cells and light-emitting diodes. Research and technology have made extraordinary progress in this field, but some issues are still to be tackled. In fact, most of the used materials contain lead, which is highly toxic. For this reason, many efforts have been made on substituting lead with other elements to design more environmentally friendly solar cells. However, devices based on lead-free materials still show relatively low efficiencies. Physical properties tuning of such materials, to improve their performance, can be achieved in different ways, and among them pressure can be thought of as a green method for this aim as well as a powerful technique to systematically explore structure–property relationships. The possibility of unveiling and discovering novel and appealing optical and electronic features, resulting from the application of an external pressure, can open an effective route to design more performing materials.