Multifunctional Properties of SrAgZ 3 (Z = Cl, Br, I): A First‐Principles Investigation

Lead‐free inorganic halide perovskites are attracting increasing interest as multifunctional materials for energy and optoelectronic applications. Here, we systematically investigate the structural, electronic, optical, thermoelectric, and photocatalytic properties of cubic SrAgZ 3 (Z = Cl, Br, I) using first‐principles calculations. Structural properties were evaluated using GGA‐PBE, while the TB‐mBJ approach was employed for improved band‐gap prediction. The calculated band gaps are 2.91, 2.17, and 0.97 eV for SrAgCl 3 , SrAgBr 3 , and SrAgI 3 , respectively, indicating tunable electronic properties with halide substitution. Strong optical absorption, exceeding 10 5 cm − 1 , and low UV reflectivity suggest favorable light‐interaction characteristics. BoltzTraP calculations within the constant relaxation‐time approximation reveal promising thermoelectric performance, with a maximum ZT of 0.71 for SrAgCl 3 at 1200 K. Band‐edge analysis indicates that direct overall water splitting is not feasible because the CBM positions are insufficiently negative for H 2 evolution. Thus, the photocatalytic potential is discussed in terms of selected redox processes rather than overall hydrogen production. Overall, the calculated multifunctional properties suggest that SrAgZ 3 compounds warrant further investigation for optoelectronic, energy‐conversion, and selected photocatalytic applications.