First‐principles quantum analysis of promising double perovskites Z2SiF6 (Z = K, Li, Na, Rb) as prospective light harvesting materials: Optoelectronic, structural and thermodynamic properties

Abstract

AbstractFor 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 Z2SiF6 (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 Z2SiF6 (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 Z2SiF6 (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 is between 1.0 and 2.0. Based on investigated optical parameters, we can say that Z2SiF6 (Z = K, Li, Na, Rb) are potential candidates for optoelectronic device applications like white LEDs (w‐LEDs). Thermodynamic parameters of Z2SiF6 (Z = K, Li, Na, Rb) are provided to establish the thermodynamic stability of these compounds.