Exploration of New Double Peroviskites Cs₂YInX₆ (X = Cl, Br, I) for Opto-Electronic and Sustainable Energy Applications

Abstract

We used theoretical and computational methods to explore the double perovskites Cs 2 YInX 6 (X = Cl, Br, I) by having the scope and goal of finding their physical aspects and characteristic. To properly explain different phenomenological features of density functional theory (DFT), the ab-initio computational model based on the approximation of full-potential augmented plane wave plus local orbitals (FP-LAPW + lo) technique was implemented. The calculated ground state properties with GGA-PBEsol agree well with the available other theoretical data. Mechanical properties, another very important aspect of these double perovskites, are found by using shear modulus, Young's modulus, and Poisson's ratio. Further, we obtained bandgaps by investigating electronic properties with and without spin-orbit coupling (SOC). In order to calculate and compare the bandgaps with experimental results, we used SOC in connection with mBJ potential to investigate the direct bandgaps of Cs 2 YInCl 6 (E g = 0.45 eV), Cs 2 YInBr 6 (E g = 0.65 eV) and Cs 2 YInI 6 (E g = 0.82 eV) respectively. Furthermore, optical properties are investigated in terms of calculations like complex dielectric constants (ε(ω)), refractive index (n(ω)), reflectivity (R(ω)) and absorption co-efficient (α(ω)) to find their possible applications in optoelectronic devices. In view of this background, BoltzTraP code will also be used to explore these double perovskites in respect of their thermoelectric applications.

Probing the opto-electronic, phonon spectrum, and thermoelectric properties of lead-free fluoride perovskites A2GeSnF6 (A = K, Rb, Cs) for energy harvesting devices

“…zT, generally referred to as the figure of merit, gauges a thermoelectric material’s aptitude for conversion 58 , 59 . The compound achieves the greatest efficiency when zT is equal to or larger than unity.…”

Study of lead free double perovskites Na2XAgCl6 (X = Ga, In Tl) for solar cells and transport applications

“…Here is my case, it depends upon Ga/In/Tl and Ag cations and Cl anion interaction as it can be seen at valence and conduction band edges in the DOS (figure 3). For example, in the literature, Cs 2 YInCl 6 has band gap 0.65 eV [46] and Rb 2 AgSbCl 6 has band gaps 2.19 eV [47]. The valence band top edge and conduction band bottom edge are located at Γ direction which ensure the direct band gap in studied DPs.…”