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Structural, electronic, optical, and mechanical properties of cubic SnZrO3 and SnHfO3 have been studied under different hydrostatic pressures within the framework of density functional theory. A strong atomic interaction resulting from a considerable drop in the lattice parameter and bond length was observed. The Sn–O and Hf/Zr–O showed strong ionic and weak covalent characteristics, respectively, and the bond strengths are found to enhance under the applied pressure. Poisson's ratio of these compounds also supports the bonding nature. The external pressure remarkably changed the optical absorption and conductivity of the materials to a higher value in the UV region of the solar spectrum and the direct bandgap of Sn(Zr/Hf)O3 significantly reduced, thereby enhancing the conductivity. Likewise, in other optical parameters, the elastic properties exhibited some noticeable changes: the stiffness, ductility, anisotropy, hardness, and machinability of these materials were significantly increased due to external pressure. All the findings indicate the high potentiality of these compounds to be used in optoelectronics and photovoltaic applications in the UV spectrum under hydrostatic pressure. [ABSTRACT FROM AUTHOR]

Metal halide perovskites have shown the most promising results as the light-harvesting section of photovoltaics and opto-electronic devices. Among the non-toxic halide perovskites, CsGeBr3 was found to be the best candidate for opto-electronic applications; however, it is understood that the efficiency of CsGeBr3 can be further increased with the insertion of transition metals as dopants. In this article, the first-principles density functional theory calculations are used to predict the mechanical, structural, electronic, and optical properties of pristine, Ni-doped, Mn-doped, and Fe-doped CsGeBr3 with 12.5% of doping concentration. All the doped materials are found to be ferromagnetic and mechanically stable. They have finite magnetization values. The optical absorption edge in all the doped materials shows that they have additional peaks within the large emission range of solar radiation, which makes them more suitable than the pristine material for photovoltaics and opto-electronic applications. Among the doped materials, Mn-doped and Fe-doped CsGeBr3 have comparably higher absorption peaks and are almost identical in shape. The electronic bandgap is smaller than the pristine structure in the case of Fe-doped CsGeBr3 and larger for Ni and Mn-doped CsGeBr3. These combinational analyses lead to the decision that, among the non-toxic, inorganic perovskite materials, Fe-doped CsGeBr3 is better suited for the use in opto-electronic applications. [ABSTRACT FROM AUTHOR]