First-principles quantum analysis of promising double perovskites Z(2)SiF(6) (Z = K, Li, Na, Rb) as prospective light harvesting materials: Optoelectronic, structural and thermodynamic properties

Abstract

For energy-efficient and high-power illumination systems, phosphor materials have attracted huge research attention over the recent decades. Herein, applying the first-principles method, we investigate and predict the optoelectronic and structural properties of light-harvesting phosphors Z(2)SiF(6) (Z = K, Li, Na, Rb) as promising candidates for weight-light-emitting diodes w-LEDs. The calculated direct energy band gaps are of order 1.56, 1.461, 1.479, and 1.585 eV for Z(2)SiF(6) (Z = K, Li, Na, Rb), respectively, thus rendering the compound's semiconducting nature suitable for optoelectronic applications. Calculated structural properties show that Rb2SiF6 is the most stable compound among Z(2)SiF(6) (Z = K, Li, Na, Rb). The optical properties in the energy range of 0-14 eV have been investigated using the well-known (GGA) formulism available in the literature. Studied compounds are active optical materials as the value of their refractive index n(?) is between 1.0 and 2.0. Based on investigated optical parameters, we can say that Z(2)SiF(6) (Z = K, Li, Na, Rb) are potential candidates for optoelectronic device applications like white LEDs (w-LEDs). Thermodynamic parameters of Z(2)SiF(6) (Z = K, Li, Na, Rb) are provided to establish the thermodynamic stability of these compounds.