Optoelectronic and thermoelectric characteristics of lead-free halide based double perovskites Rb <sub>2</sub> GaInX <sub>6</sub> (X = Cl, Br, I) for solar cell applications
Ayesha Ejaz, Ghulam Mustafa, Muhammad Nasir Amin, N.A. Noor, Hamid Ullah, R. Neffati
Abstract
Abstract For the fabrication of thermoelectric and optoelectronic devices, metal halide perovskite materials are perfect applicants. In this work, first-principles computation is carried out to explore the structural, optical, electronic, and transport features of Rb 2 InGaX 6 (X = Cl, Br, I).In structural calculations, the obtained value of Paugh’s ratio(B/G) reveals the material’s brittleness. The acquired negative value of enthalpy of formation (∆H f ) exposes the studied materials are stable. The exploitation of band structure exhibits that the Rb 2 InGaX 6 (X = Cl, Br) compound possesses an indirect bandgap value of 2.20eV for Cl, which significantly decreases to 0.90 eV by substituting anion from Cl up to I. The materials under observation possess a remarkable absorption coefficient α ( ω ) in ultraviolet and visible region (2–8eV) of light spectra, which makes it practical for photocell and optical device fabrication. Furthermore, the transport features are estimated by utilizing the BoltzTrap code within the temperature range of 200–500 K. The calculated value of the figure of merit (ZT) indicates that Rb 2 GaInX 6 (X = Cl, Br, I) compounds are a potential candidate for thermoelectric device applications.