Multifunctional properties of CaAlCl3 and CaAlI3 halide perovskites: first-principles insights into halogen substitutionL. Boughlima, S. Dahri, A. Jabar, L. Bahmad, L. B. Drissi, and R. Ahl Laamara Science Faculty, LPHE-MS, Mohammed V University in Rabat, Rabat, Morocco
E-mail: ja.abderrahim@gmail.com Received: 29 November 2025 Accepted: 17 January 2026 Abstract: This theoretical study focused on the different attributes, such as structural, mechanical, electronic, thermodynamic, and optical aspects, based on first-principal DFT calculations for the halide perovskite compounds CaAlCl3 and CaAlI3. The Wien2k package was used to conduct calculations under the GGA and mBJ schemes for enhanced band gap estimations. Results demonstrate that the replacement of the smaller Cl− ion for the larger I− leads to increases in lattice constant and volume, and mechanical stiffness was reduced, with CaAlI3 exhibiting a reduction in bulk modulus which indicates weaker Al-I bonding relative to Al-Cl. Both compounds are semiconductors with CaAlCl3 exhibiting the larger band gap of 4.208 eV and CaAlI3 of 2.778 eV, primarily due to the delocalized I-5p orbitals. From the thermal aspect, CaAlI3 shows higher thermal expansion and thermal heat capacity of the compound. Furthermore, the compound shows strong visible light absorption located at ~ 2.8 eV, which further confirms its potential for photovoltaic usage. In contrast, CaAlCl3 can be used for optical insulation as it is UV transparent and does exhibit Cl visible light. These findings clearly show that different halogen substitutions can be used to tailor the multifunctional attributes of halide perovskites for targeted optoelectronic and energy device applications. Keywords: Halide perovskite CaAlX3; Structural; Electronic; Mechanical; Optical properties Full paper is available at www.springerlink.com. DOI: 10.1007/s11696-026-04682-z
Chemical Papers 80 (5) 5717–5730 (2026) |
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