Characterization and Photophysical Properties of Tricalcium Phosphates Prepared by Using the Solid-State Reaction Process

Abstract

Rare-earth-doped phosphors for near ultraviolet excitation are under an extensive research for applications to white-light-emitting diodes. In this study, we prepare red-orange emitting samarium-doped rhombohedral tricalcium phosphate particles by using the solid-state reaction method. The synthesis procedures are reported, the formation of prepared particles is confirmed using X-ray diffraction patterns, and the morphology and the elemental composition are measured using a scanning electron microscope. We also investigate the photophysical properties of trivalent samarium-doped tricalcium phosphate phosphors by taking absorption, excitation, and emission spectra at room temperature. We show that the trivalent samarium-doped tricalcium phosphate phosphors are red-emitting phosphors and have higher efficiency with near ultraviolet excitation. The emission intensity increases very sharply up to a samarium concentration of 2.5 mol% and then decreases as the concentration increases. Therefore, the samarium doping concentration in the tricalcium phosphate phosphor needs to be optimized.