Structural, electronic, optical, elastic, thermodynamic and thermal transport properties of Cs2AgInCl6 and Cs2AgSbCl6 double perovskite semiconductors using a first-principles study

Abstract

In this study, we employ the framework of first-principles density functional theory (DFT) computations to investigate the physical, electrical, bandgap and thermal conductivity of Cs₂AgInCl₆-CAIC (type I) and Cs₂AgSbCl₆-CASC (type II) using the GGA-PBE method. CAIC possesses a direct band gap energy of 1.812 eV, while CASC demonstrates an indirect band gap energy of 0.926 eV. The CAIC and CASC exhibit intriguingly reduced thermal conductivity, which can be attributed to the notable reduction in their respective Debye temperatures, measuring 182 K and 135 K, respectively. The Raman active modes computed under ambient conditions have been compared with real-world data, showing excellent agreement. The thermal conductivity values of CAIC and CASC compounds exhibit quantum mechanical characteristics, with values of 0.075 and 0.25 W m⁻¹ K⁻¹, respectively, at 300 K. It is foreseen that these outcomes will generate investigations concerning phosphors and diodes that rely on single emitters, with the aim of advancing lighting and display technologies in the forthcoming generations.