A2LiGaI6 (A = Cs, Rb): New lead-free and direct bandgap halide double perovskites for IR application

Anwar Ul Haq; Tasawer Shahzad Ahmad; Afaq Ahmad; Badriah S Almutairi; Muhammad Amin; M I Khan; Nimra Ehsan; Ramesh Sharma

doi:10.1016/j.heliyon.2023.e21702

A₂LiGaI₆ (A = Cs, Rb): New lead-free and direct bandgap halide double perovskites for IR application

Heliyon. 2023 Oct 30;9(11):e21702. doi: 10.1016/j.heliyon.2023.e21702. eCollection 2023 Nov.

Authors

Anwar Ul Haq¹, Tasawer Shahzad Ahmad², Afaq Ahmad³, Badriah S Almutairi⁴, Muhammad Amin¹, M I Khan¹, Nimra Ehsan⁵, Ramesh Sharma⁶

Affiliations

¹ Department of Physics, The University of Lahore, 53700, Pakistan.
² Department of Physics, University of Okara, Pakistan.
³ Centre of Excellence in Solid State Physics, University of the Punjab, Lahore, Pakistan.
⁴ Department of Physics, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, Riyadh, 11671, Saudi Arabia.
⁵ Department of Chemistry, The University of Lahore, 53700, Pakistan.
⁶ Deptment of Applied Science, Feroze Gandhi Institute of Engineering and Technology, Raebareli, 229001, Uttarpradesh, India.

Abstract

Recently, all inorganic double perovskites have drawn a lot of interest as promising solar materials. The optical, structural, thermoelectric, electronic, and mechanical properties of double halide perovskites A₂LiGaI₆ (A = Cs, Rb) are explored via first-principles calculations with the WIEN2k code, using GGA PBEsol and TB-mBJ potentials. The majority of perovskite materials utilized in the highest-performing solar cells have bandgaps ranging between 1.48 and 1.62 eV. The compounds A₂LiGaI₆ (A = Cs, Rb) have a direct bandgap of 1.51 eV and 1.55 eV, respectively, and are expected to be useful in solar cells. The optical study shows that there are large absorption bands in the visible region, as determined by the dielectric constant, absorption, and other dependent factors. Their potential for use in solar cells is increased by their absorption in the visible part. The BoltzTraP code has been used to perform thermoelectric studies to assess the electrical, thermal conductivities, and Seebeck coefficient. They are important for construction of thermoelectric generators that harvest heat energy because of their high figure of merit and incredibly low thermal conductivity of lattice at ambient temperature. Furthermore, by examining the spectroscopic limit maximum efficiency, up to 30 % efficiency is predicted for both compositions, which paves the way for the applicability of them in solar energy conversion.

Keywords: Density functional theory; Double-perovskite; Lead-free; Optical properties; Photoelectric; Solar cell; TB-mBJ.