Using Eu2O3 to dope, Eu2+-activated Ca2Si5N8 phosphors were synthesized and their luminescence properties were investigated. Dark yellow and orange day-light-colored phosphors were achieved with broad and high absorption in the ultra violet (UV)/ visible range of 300-550 nm. The photoluminescence characteristics with various Eu2+-doping concentrations were observed. The oxidation from Eu2O3 influenced not only emission but also the excitation spectra of the phosphors. Broad band emissions were achieved and the strongest peak positions were shifted from 588 to 613 nm with an increase of the dopant, Eu2O3 concentration. A large emission tunability and a high solubility of activators-h absorption in the UV range and broad red emission make phosphors in this study excellent candidates for UV-light emitting diode (LED) conversion phosphors.

Keywords: Eu2+, Ca2Si5N8, Phosphor, Oxidation, UV-LED.