Stimulating band gap reduction of AZnF3 (A = Ga, In) perovskites under external pressure for improving optoelectronic performance

This study extensively examines the influence of pressure on several physical characteristics of cubic halide perovskites AZnF₃ (A = Ga, In) in extreme conditions (up to 60 GPa hydrostatic pressure) via the use of the first principles approach. The reduction of the band gap of the chosen compounds under increasing pressure is comprehensively discussed through the band structure and density of states calculations. The strong hybridization between Ga-4p(In-5p) and F-2p states under pressure is responsible for lowering the electronic band gap. The ionic and covalent nature of Ga/In–F and Zn–F bonds, respectively, are confirmed by charge density mapping. The optical absorption shifts towards lower energy regions under pressure are advantageous for using AZnF₃ (A = Ga, In) in photovoltaic applications. Furthermore, the comprehensive optical study demonstrates that the compound synthesized under pressure exhibits greater suitability for use in optoelectronic devices compared to systems formed under zero-pressure conditions. Interestingly, the brittleness of GaZnF₃ is converted to ductile under the application of pressure.