Bandgap Assessment of Compositional Variation for Uncovering High‐Efficiency Improved Stable All‐Inorganic Lead‐Free Perovskite Solar Cells
R. Thandaiah Prabu, S. Malathi, Atul Kumar, Bandar Ali Al‐Asbahi, A. Laref
Abstract
Bandgap evolution with composition variation of ABX 3 perovskites is explored, where A = MA, FA, Cs, Rb; B = Pb, Sn, Ge; and X = I, Br, Cl. To identify alternative lead‐free and stable perovskite‐absorbing compositions, all possible combinations of compositions are screened under constraints of structural stability and optimal bandgap values. The comparative analysis reveals Cs‐, Rb‐, and Ge‐based perovskite as an alternative to MAPbI 3 's toxicity and stability issues. The Cs‐, Rb‐, and Ge‐based perovskites are lead free and structurally stable, with the requisite optical cum electrical properties. The numerical simulation of the proposed Cs 1− y Rb y Ge(Br x I 1− x ) 3 ‐based device shows efficiency above the 22% mark. All aspects of the proposed device are identical to MAPbI 3 , except that the MAPbI 3 absorber is replaced with a Cs 1− y Rb y Ge(Br x I 1− x ) 3 ‐based absorber.