Unveiling phase dependent physical properties of cubic and hexagonal CsCdBr3: a DFT approach

Abstract

The distinctive structural, optoelectronic, photocatalytic, and elastic properties of CsCdBr₃ make it appropriate for cutting-edge technological applications. Important ground-state properties of the cubic and hexagonal phases of CsCdBr₃ are investigated in this work using density functional theory (DFT). Both phases are energetically and mechanically stable. Electronic band structure analysis revealed that both CsCdBr₃ polymorphs exhibit semiconducting character. The cubic phase shows an indirect bandgap (2.74 eV) while the hexagonal phase possesses a direct bandgap (4.26 eV). The density of states (DOS), Mulliken bond, and charge density distribution provide orbital contributions to the band structure and bonding nature of the polymorphs. The calculated redox potential suggested that both compounds are capable of water splitting as well as breaking down biological contaminants under UV-vis radiation. By analyzing the different elastic parameters, it can be concluded that both polymorphs are soft and ductile in nature. The cubic phase exhibits better transport properties, while the hexagonal phase showcases a degree of anisotropy in thermal properties. The optical characteristics correspond well with the electronic band structure. The high absorptivity in the UV region, lower reflectivity, and optical anisotropy of the hexagonal polymorph suggested that these could be a potential candidate for applications in the photovoltaic solar industry as well as to design waveguides, dielectric condensers, light emitting diodes (LEDs), and thermoelectric and sensing devices.