Interphase strategy tames Zn and Sn migration, boosting CZTSSe cells past 15% efficiency

Safe, efficient, and economical light-absorbing (photovoltaic) technology is key to developing the next generation of solar cells. Cu2ZnSn(S,Se)4 (CZTSSe) photovoltaics—using the easily accessible elements copper, zinc, tin, and sulfur and/or selenium—hold great promise thanks to their abundant elemental reserves, low cost, high stability, and non-toxic properties. Therefore, improving the efficiency of CZTSSe photovoltaic cells is an important focus of research.