Preparation of Eu³⁺ ions activated Ca₂La₈(SiO₄)₆O₂ oxyapatite nanophosphors through two-step surfactant-free method and their optical and electrical properties

Eu³⁺ ions activated Ca₂La₈(SiO₄)₆O₂ (CLSO):Eu³⁺ nanophosphor samples were synthesized by a mixed solvothermal and hydrothermal method. The samples were carefully studied using various characterization techniques. The XRD patterns of CLSO:Eu³⁺ and CLSO confirmed that the samples were crystallized in hexagonal phase with a space group of P6₃/m (176). The morphology of the nanoparticles was studied by varying the reaction parameters such as growth, temperature and time. The photoluminescence (PL) excitation and PL emission spectra exhibited the typical Eu³⁺ bands in the wavelength range of 200–550 nm and 400–750 nm, respectively. The intensity of the ${}^5{D}_0\to {}^7{F}_2$ electric dipole (ED) transition peak was strong in the PL emission spectrum which imparts the red color when observed under ultraviolet light. The ED transition peak intensity increased when the sample was calcined at an elevated temperature of 700 °C, indicating improved asymmetry ratio and good chromaticity coordinates. The electrical properties of the prepared materials were studied by spin-coating the powder dispersed solutions on the silica substrate. The output current values were also measured for the CLSO nanoparticles prepared under different growth conditions. These results showed the advantages of CLSO nanoparticles for their application in optics and feasibility in nanoelectronic and energy harvesting devices. (paper)