We used density functional theory (DFT) to explore the structural relaxation, optoelectronic characteristics, and thermodynamic stability of the lead-free quasi-zero-dimensional halide perovskites (0D-HPs) Cs 2 MX 5 (M = Sb/Bi; X = Cl/Br/I). The ground state/optimized structure parameters were used to calculate the physical properties of these HPs through modified Becke-Johnson (mBJ) exchange potential. The crystal structure of these compounds is made up of separate MX 6 octahedra that are held together by halide ions. The studied quasi-0D HPs possess direct band gaps ranging from 1.55 to 3.91 eV. The edge of the valence band (VB) is mostly made up of X-p orbitals, with a small involvement of Cs-s and M-p orbitals, making up the lower conduction band (CB). Optical coefficients show that these quasi-0D HPs have good dielectric characteristics, making them suitable for use in optoelectronic devices. Thermodynamic studies also show that these materials have better heat conductivity, structural stability, and increased mechanical hardness.
Wakil et al. (Fri,) studied this question.