First-principles study of structural, electronic, optical and thermoelectric properties of rare earth based perovskites XAlO3 (X = Sm, Eu, Gd)

[Display omitted] •The results of this paper reveal the fact that the crystal XAlO3 (X = Sm, Eu, Gd) is promising for energy-devices applications.•The hundred percent polarization due to their half metallic natures make candidate materials for spintronic devices.•These materials show best response to the ultraviolet-region which is clear for their dielectric functions, refractive index, absorption coefficient, extinction coefficient, optical conductivity, reflectivity, and energy loss function.•They also show outstanding thermoelectric properties. First-principles method based on density functional theory calculations are employed for investigating the electronic, optical and thermoelectric properties of XAlO3 (X = Sm, Eu, Gd) for energy-devices applications. The spin-polarized electronic spectra of XAlO3 depicts their half metallic nature since mere the spin up channel crosses the fermi level. Further, the optical features for instance; the dielectric functions, refractive index, absorption coefficient, extinction coefficient, optical conductivity, reflectivity, and energy loss function are studied which predict that these compounds are supposed to be better materials for the ultraviolet-region based optoelectronic and energy devices. Thermoelectric properties in terms of electrical and thermal conductivity, and figure of merit show higher values of thermoelectric characters which is extremely significant for optoelectronic devices. Interestingly, the positive value of Seebeck coefficient indirectly depict that XAlO3 is a p-type materials.