Vacancy defects on structural and optoelectronic properties of double perovskite Cs2AgInCl6: A density functional theory investigation

Abstract This study systematically investigates the effects of Cs, Ag, In, and Cl vacancy defects on the structure, electronic, and optical properties of double perovskite Cs 2 AgInCl 6 through density functional theory calculations. The research demonstrates that different vacancy structures lead to a reduction in the stability of the structure, with Cs 2 AgInCl 6 : V Cl showing relatively lower impact and Cs 2 AgInCl 6 : V cs exhibiting the a more pronounced effect. The vacancies alter the conductivity of Cs 2 AgInCl 6 , where Cs 2 AgInCl 6 : V In and Cs 2 AgInCl 6 : V Cl exhibit p-type and n-type conductivity, respectively. Cs 2 AgInCl 6 : V Cs and Cs 2 AgInCl 6 : V Ag remain direct bandgap semiconductors with band gaps of 2.672 eV and 3.859 eV, respectively. Additionally, the study investigates the real and imaginary parts of the dielectric constants as well as the optical absorption coefficient to explore the material’s optical properties. Regarding optical properties, different vacancy defect systems exhibit distinct absorption capabilities in the visible and ultraviolet light ranges, with the material demonstrating optimal optical performance as the incident photon energy increases. These research findings provide essential references for a deeper understanding of perovskite materials’ properties and optimizing the performance of optoelectronic devices. Future research can further explore the influence of other defect types and external conditions on material properties to expand its potential applications in solar cells, optical communications, metamaterials, and other fields.