Lead-free semiconductors with high absorption: insight into the optical properties of K2GeSnBr6 and K2GeSnI6 halide double perovskites
M. Houari+, B. Bouadjemi+, A. Abbad+, T. Lantri+, S. Haid+, W. Benstaali+, M. Matougui+, S. Bentata+*
+Laboratory of Technology and of Solids Properties, Abdel Hamid IbnBadis University, 27000 Mostaganem, Algeria
*Laboratory of Quantum Physics of Matter and Mathematical Modeling (LPQ3M), Mustapha Stambouli University of Mascara,
29000 Mascara, Algeria
Structural, electronic and optical properties for halidedouble perovskites compounds K2GeSnBr6 and K2GeSnI6 are studied in this work.
Based on the (FP-LAPW) method, the previous properties are treated
within the (GGA-PBE) and the (mBJ-GGA) approximations. The results show that these compounds
are stable in the non-magnetic phase (NM). Electronic properties indicate that these compounds have a
semiconductor behavior with a direct band gap. The calculated formation energy and cohesive energy
indicate that these alloys have good chemical stability. High absorption coefficient and high
reflectivity prove that these materials are appropriates for optoelectronic applications, including
solar and photovoltaic cells.