First-Principles Investigation of the Optoelectronic Properties, Photocatalytic Activity and Solar Cell Efficiency of Rb 3 Cr 2 X 9 (X= Cl, Br and I) Halide Perovskites

Chromium-based halide perovskites semiconductors Rb 3 Cr 2 X 9 (X = Cl, Br and I) are explored within the frame work of density functional theory (DFT). The optimized structural parameters show consistency with the experimental work and the lattice parameters are systematically increases as with the size of X anion. The magnetic optimization calculations reveal the antiferromagnetic nature for all these perovskites. The electronic properties through GGA + mBJ confirm semiconducting nature for these compounds with bandgaps 1.79, 1.65 and 1.36 eV respectively. The optical results show their suitability for optoelectronic device technology within the wide spectral region. The calculated elastic parameters show the mechanical stability and incompressibility of these compounds. Rb 3 Cr 2 Cl 9 has ductile nature while Rb 3 Cr 2 Br 9 and Rb 3 Cr 2 I 9 are brittle. The solar cell (SC) efficiency simulations of the WS 2 /Rb 3 Cr 2 X 9 spiro-MeOTAD/Cu device through SCAPS-1D package have been performed. The estimated PCE (%) of these perovskites are 26.60, 28.27 and 30.13 respectively and show that Rb 3 Cr 2 I 9 is more efficient. Theoretical analysis predicted that Rb 3 Cr 2 Br 9 is a suitable compound for photocatalysis applications.