Optoelectronic and thermoelectric properties of double halide perovskite Cs2AgBiI6 for renewable energy devices

Density function theory-based calculations investigate the structural, electronic, optical, and thermoelectric properties of bismuth-based double halide perovskite Cs2AgBiI6 for renewable energy devices. Our calculations show that these perovskite materials have good structural stability with a tolerance factor of ������ = 0.846 and formation energy of ������������ = -0.88 eV. The electronic properties are approximated using GGA-PBE and TB-mBJ while adding spin-orbit coupling. The compound exhibits indirect band gap semiconductor behavior with good absorption in the visible (60 x 104 cm-1 at 4 eV) and ultraviolet regions (160 x 104 cm-1 at 11.5 eV). Therefore, the compound is a good candidate for solar cells. In addition, the thermoelectric properties in the temperature range of [100-800 K] were studied using the BoltzTraP code. The studied thermoelectric properties of Cs2AgBiI6 double halide perovskite prove that it is an excellent candidate for thermoelectric applications.