First-principles simulation study on the impact of monovalent Cu ion doping on the crystal structure and electrical properties of lead-free perovskite Cs2AgBiBr6

Abstract

BackgroundLead-free double perovskite Cs2AgBiBr6 has garnered significant attention in the field of nuclear radiation detection as an environmentally friendly material. Experimental observations have revealed that doping Cs2AgBiBr6 with Cu+ significantly enhances the material's stability and photoelectric conversion efficiency.PurposeThis study aims to investigate the impact of Cu+ doping on the crystal structure and electrical properties of Cs2AgBiBr6.MethodsBased on density functional theory, first-principles calculations were applied to exploring the effects of Cu+ doping on the structure and electrical properties of Cs2AgBiBr6. Structural properties, such as the stability, doping formation energy, lattice parameters, elastic constants, of Cu+ doping on the lead-free double perovskite Cs2AgBiBr6 were investigated by simulation whilst the band analysis and density of states analysis were employed to study the impact of electrical performance.ResultsThe results indicate that Cu+ doping enhances the stability of Cs2AgBiBr6. The Cs2Ag1-xCuxBiBr6 compounds formed by doping, as well as the original Cs2AgBiBr6 material, exhibit indirect bandgap semiconductor behavior. The bandgap significantly narrows with an increase in the Cu+ doping ratio. Based on an analysis of the density of states (DOS), the bandgap narrowing can be attributed to the downward shift of the conduction band minimum dominated by Bi6p orbitals due to Cu+ doping.ConclusionsCs2Ag1-xCuxBiBr6 exhibits greater stability and superior electrical properties compared to Cs2AgBiBr6, making it a promising candidate material for semiconductor radiation detectors.

Keywords

• first-principles calculations
• cs2ag1-xcuxbibr6
• nuclear radiation detection
• electronic structure
• cu+ doping