Theoretical prediction of optoelectronic and thermoelectric properties of RbXO2 (X = Al, Ga, In) for renewable energy applications.

Calculated Debye temperature (θ D), average sound velocity (υ m), melting temperature (Tm) for RbXO 2 (X = Al, Ga, In) oxides. • The optoelectronic and thermoelectric properties of RbXO 2 (X = Al, Ga, In) oxides have been investigated. • The structural stability of RbXO 2 oxides has been confirmed from Goldschmidt's tolerance factor. • The direct bandgap nature of the RbXO 2 oxides is observed. • The thermal efficiency increases from Al to In, because bandgap decreases that increases the electrical conductivity. The optoelectronic and thermoelectric properties of RbXO 2 (X = Al, Ga, In) oxides have been investigated by using the density functional theory (DFT). The stability of RbXO 2 has been confirmed from the negative value of enthalpy of formation, Goldschmidt's tolerance factor (0.91, 0.95 and 1.02) and Born mechanical stability criteria. The bandgap of the studied RbXO 2 lies in the range from 3.3 eV to 1.25 eV, which shifts the optical region from near ultraviolet to near infrared region of spectrum. The comparative analysis of optical and thermoelectric properties shows RbXO 2 are more suitable for optoelectronic applications than thermoelectric applications. [ABSTRACT FROM AUTHOR]