Pressure-driven modification of optoelectronic features of ACaCl 3 (A = Cs, Tl) for device applications.

Intending to advance the use of halide-perovskites in technological applications, in this research, we investigate the structural, electronic, optical, and mechanical behavior of metal-halide perovskites ACaCl ₃ (A = Cs, Tl) through first-principle analysis and assess their potential applications. Due to the applied hydrostatic pressure, the interaction between constituent atoms increases, thereby causing the lattice parameter to decrease. The band structure reveals that band gap nature transits from indirect to direct at elevated pressure. Moreover, at high pressure, the electronic band structure shows a notable band gap contraction from the insulator (>5.0 eV) to the semiconductor region, which makes them promising for electronic applications. The charge density map explores the ionic and covalent characteristics of Cs/Tl-Cl and Ca-Cl under pressured and unpressurized environments. Induced pressure enhances the optical conductivity as well as the optical absorption that moves toward the low-energy region (red shift), making ACaCl ₃ (A = Cs, Tl) advantageous for optoelectronic applications. Additionally, this study reveals that the mechanical properties of ductility and anisotropy were found to be improved at higher pressures than in ambient conditions. Overall, this study will shed light on the technological applications of lead-free halide perovskites in extreme pressure conditions.
Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(© 2024 The Authors.)