First-Principles Exploration of the Mechanical Flexibility and Multifunctional Properties of Aluminum- and Zinc-Based...

The present study employs density functional theory to examine structural, optoelectronic, mechanical, and transport characteristics of ternary chalcopyrites semiconductors Al₂ZnCh₄ (X = Se, Te) to investigate their multifunctional potential. Structural optimization supports the materials' thermodynamic stability in the tetragonal phase. The mechanical properties, determined through elastic constants and moduli, exhibit mechanical stability and ductility, with softness rising from S to Te, rendering them suited to flexible device applications. Optical features reveal high absorption in the visible to ultraviolet range, with peak absorption shifting towards lower energies as chalcogens change from Se to Te. This feature demonstrates its potential for solar energy accumulation and UV protection applications. Thermoelectric study displays strong Seebeck coefficients (> 300 μV/K), moderate electrical conductivity, and low electronic thermal conductivity. Al₂ZnTe₄ exhibits the greatest power factor. The dimensionless figure of merit of Al₂ZnSe₄ and Al₂ZnTe₄ improves with temperature, attaining maximum values, demonstrating their potential for high-temperature thermoelectric applications.