Probing direct bandgap of double perovskites Rb2LiTlX6 (X = Cl, Br) and optoelectronic characteristics for Solar cell applications: DFT calculations

Abstract

A fascinating novelclass of double perovskites materials with interesting optoelectronic and transport features have been discovered. In the current study, optoelectronics and the transport properties of Rb2LiTlX6 (X = Cl, Br) were comprehensively examined. Structure stability was confirmed by calculating tolerance factor value and Born stability criteria. At the Γ-symmetry point, direct band gaps of 2.90 eV and 1.66 eV are observed, ensuring spectral response throughout ultra-violet to visible areas and used as potential candidates for solar cell applications. These are excellent compounds for optoelectronic applications because of their low scattering of light, refractive index range approximately from 1.5 to 2, and wide absorption band in visible areas. Furthermore, thermal properties with the name electrical conductivity, thermal conductivity, Seebeck coefficient, power factor, and figure of merits of double perovskites were studied. The figure of merits (ZT) values of both compounds are 0.43, and 0.51 at room temperature, which confirms that these materials are suitable for use in thermal devices.

Keywords

• Halide double perovskites
• DFT investigations
• Direct band gap
• Optical properties
• Transport properties