Understanding the stability concerns and electronic structure of CsYbX3 (X=Cl,Br) halidoperovskites for optoelectronic applications

Highlights: • Cubic phase stability from the phonon dynamics and machinability of these structures is established. • HSE approximated relaxed structural parameters are in accord with the previous experiments. • The semiconducting band structures are calculated with energy gap of 3.99 eV and 3.68 eV for CsYbCl₃ and CsYbBr₃ alloys, respectively. • Debye temperatures evaluated are 181 K for Cl and 141 K for Br- based alloys. • The dielectric constant optical conductivity, electron loss function, refractive index provide a fundamental basis of the feasible optical characteristics suitable for optoelectronic devices and application. -- Abstract: Here we discuss the electronic structure and optical properties of Yb based halide perovskites with keen interest on phonon and mechanical stability using the HSE06 approximated density functional theory calculations. The experimental structural parameters are exploited to calculate the semiconducting band structures with energy gap of 4.32 eV and 3.68 eV for CsYbCl₃ and CsYbXBr₃ alloys, respectively. Cubic phase stability is guaranteed by the phonon dynamics and machinability of these structures. The observed relaxed structural parameters are in accord with the previous experiments. We found that the present halide perovskite compounds are semiconductors with tuneable band gaps and the f-states of Yb element play a significant role in defining the electronic structure. In addition to this, the sound velocities accompanied by the Debye temperatures (181 K for Cl and 141 K for Br) are evaluated. Furthermore, the dielectric constant optical conductivity, electron loss function, refractive index provide a fundamental basis of the feasible optical characteristics suitable for optoelectronic devices and applications.