First principles investigation of halide based Rb2NaGaZ6 (Z = Br, I) double perovskites for energy harvesting applications

Huda A Alburaih; Ghulam M Mustafa; Pakeeza Aymen Nawaz; Sadaf Saba; N A Noor; Asif Mahmood; Ramesh Sharma

doi:10.1039/d3ra05060b

First principles investigation of halide based Rb₂NaGaZ₆ (Z = Br, I) double perovskites for energy harvesting applications

RSC Adv. 2023 Dec 8;13(51):35799-35809. doi: 10.1039/d3ra05060b.

Authors

Huda A Alburaih¹, Ghulam M Mustafa², Pakeeza Aymen Nawaz³, Sadaf Saba⁴, N A Noor⁵, Asif Mahmood⁶, Ramesh Sharma⁷

Affiliations

¹ Department of Physics, College of Science, Princess Nourah Bint Abdulrahman University P.O. Box 84428 Riyadh 11671 Saudi Arabia.
² Department of Physics, Division of Science and Technology, University of Education Lahore Punjab 54770 Pakistan dr.ghulam.muhammad@ue.edu.pk.
³ Department of Physics, University of Lahore Lahore Pakistan.
⁴ Center of Excellence in Solid State Physics, University of the Punjab Lahore Pakistan.
⁵ Department of Physics, RIPHAH International University, Campus Lahore Pakistan.
⁶ Chemical Engineering Department, College of Engineering, King Saud University Riyadh Saudi Arabia.
⁷ Dept. of Applied Science, Feroze Gandhi Institute of Engineering and Technology Raebareli 229001 Uttarpradesh India.

Abstract

Extensive investigations have been conducted on the thermoelectric and optoelectronic characteristics of double perovskite compounds using the full potential linearized augmented plane wave (FP-LAPW) approach. Here we investigated Rb₂NaGaZ₆ (Z = Br, I) to explore its band structure, and electronic, optical and transport properties. Born's stability criteria have confirmed the mechanical stability of these compounds. Analysis of the elastic properties reveals their ductile nature, as indicated by a Poisson coefficient (υ) greater than 0.26 and a Pugh ratio exceeding 1.75 for Rb₂NaGaZ₆ (Z = Br, I). Computation of the bandgap values shows that both compositions possess a direct bandgap nature, with respective values of 2.90 eV and 1.25 eV. This suggests that substituting Br with I brings the band edges closer together, resulting in a decrease in the bandgap value. The optical properties are assessed based on the absorption coefficient, reflectivity, and dielectric constants. The thermoelectric properties, including thermal and electrical conductivities, power factor (PF), and figure of merit (ZT), are determined using the BoltzTrap code. The ZT values indicate that both compositions exhibit promising potential for various transportation applications.