Abstract
Optoelectronic properties and high power conversion efficiency make lead halide perovskites an ideal material for solar cell applications. However, the toxic nature of lead and the instability of organic cations limit their use and commercialization. Suggesting an alternative, we present our DFT-based first principles calculations of A(2)PdBr(6) (A = K, Rb, and Cs) using the highly acclaimed modified Becke Johnson (mBJ) and hybrid functional (HSE) approximations. We report on a strong optical absorption in the visible region with small effective mass and indirect band gap of 1.84, 1.53, and 1.54 eV for K2PdBr6, Rb2PdBr6, and Cs2PdBr6, respectively. Our results suggest that Rb2PdBr6 and Cs2PdBr6 are suitable compounds for applications as light absorption layers in perovskite solar cells. Also, the calculated thermoelectric figure of merit indicates their possible use in thermoelectric energy devices.