Strain-induced changes in the electronic, optical and mechanical properties of the inorganic cubic halide perovskite Sr3PBr3 with FP-DFT

In recent years, inorganic perovskite materials have garnered significant attention in solar technology due to their outstanding structural, optical, mechanical, and electronic properties. A comprehensive investigation, employing first-principles density-functional theory, was conducted to assess the impact of compressive and tensile strain on the optical and electrical properties of cubic perovskite Sr3PBr3. The unstrained Sr3PBr3 exhibits a direct bandgap of 1.528 eV/2.32 eV with PBE/HSE functions at the Gamma point. Under compressive strain, the bandgap decreases (1.23 eV at -4% strain), leading to a redshift in the absorption coefficient spikes, while tensile strain results in a slight bandgap increase (1.723 eV at +4 % strain) and a blueshift in absorption coefficient spikes. Total density of states was computed as 18.75 and 1.60 electrons/eV at VB and CB without strain. The value of static dielectric constant was measured as 5.24. The initial critical point of dielectric constant, large absorption peak, and maximum loss function were calculated at 1.47, 7.28, and 9.15 eV without strain. The material demonstrates excellent light absorption in the range of visible light, aligning with its electronic properties. The Sr3PBr3 perovskite is therefore thought to be perfect for usage in solar cells for the generation of power and light control.