Quantum chemical investigation of A2LiBiI6 perovskites with Na, K, and Rb for photocatalytic water-splitting application

Perovskite materials have received a lot of attention due to their distinctive structural, electronic, and optical characteristics, particularly in photocatalytic water splitting applications. This work aims to explore structural, electronic, optical, elastic, and mechanical properties of cubic-phase A2LiBiI6 (A = Na, K, Rb) double perovskites using DFT within the GGA-PBE framework. All compounds exhibit negative formation energies (−1.45, −1.14, and −1.07 eV) along with the tolerance factors ranging from 0.820 to 0.896, which fall within the perovskite stability domain. In the phonon dispersion analysis of all compounds, no imaginary frequencies appeared, confirming their dynamic stability. The materials…