Comprehensive stability assessment and photovoltaic applications of double halide perovskites K2TlAlX6 (X = Cl, Br): a DFT studySadaf Nayab, Naimat Ullah Khan, Arshad Khan, Roshan Ali, Aman Ullah, and Amjad A. Almunyif Department of Physics, University of Science and Technology Bannu, Bannu, Pakistan
E-mail: nukhan.ustb@gmail.com Received: 1 January 2025 Accepted: 4 June 2025 Abstract: This study explores the stability and potential of cost effective, lead-free double perovskites K2TlAlX6 (X = Cl, Br) for solar energy harvesting applications. Utilizing density functional theory simulations within the WIEN2k package, we found that both compounds crystallize in cubic phases (space group Fm-3 m). Calculations of formation energy, tolerance factor, and ab-initio molecular dynamics (AIMD) simulations confirm the thermodynamic, structural, and thermal stability of our predicted materials. We calculated the electronic band structure of the studied materials using TB-mBJ, HSE06, and SOC functionals, and found them to be indirect semiconductors, with band gap values of 1.22/1.98/1.28 eV and 1.06/1.622/1.11 eV, respectively for K2TlAlX6 (X = Cl, Br) compounds. Additionally, we calculated the electron–hole pair generation energy and exciton binding energy, both of which are comparable to those of silicon (Si) and methylammonium lead iodide (MAPbI3), suggesting promising optoelectronic performance. Elastic constant calculations confirm mechanical stability, anisotropy, and ductility. Furthermore, analysis of optical properties demonstrates high absorption coefficients (~ 104–105 cm−1) and absorption efficiency (~ 90%) across the entire visible range, emphasizing the potential of our simulated materials for photovoltaic applications. Keywords: DFT; Stable double pervoskites; Solar energy; Optical properties; Mechanical properties Full paper is available at www.springerlink.com. DOI: 10.1007/s11696-025-04183-5
Chemical Papers 79 (9) 6195–6213 (2025) |
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