Defect activity in metal halide perovskites with wide and narrow bandgap

Metal halide perovskites (MHPs) constitute a rich library of materials with huge potential for disruptive optoelectronic technologies. Their main strength comes from the possibility easily tuning their bandgap to integrate them in devices different functionalities — principle. In reality, this cannot be achieved yet. fact, whereas defect tolerance can claimed MHPs about 1.6 eV, model system that is object intense investigations, lower and higher bandgaps are far being defect-tolerant. These show various forms instabilities mainly driven by strong activity. Here we critically assess most recent advances elucidating physical chemical activity defects both high-bandgap low-bandgap MHPs, while correlating it performance stability losses, especially solar cells, driving application these materials. We also provide an overview strategies so implemented eventually overcome remaining materials-based device-based challenges.