Solid state reaction preparation and enhanced red luminescence of S-doped La2Mo2O9:Pr3+phosphors

Red-light-emitting phosphors of La2Mo2O9:Pr3+ and S-doped La2Mo2O9:Pr3+ were prepared by high temperature solid state reaction. Under the excitation of 450 nm blue light, all samples produced a red emission peak at 650 nm corresponding to the characteristic transition of Pr3+ (3P0→3F2). The dependence of Pr3+ doping content (x) on the luminescent intensity was analyzed, and the optimal doping content of Pr3+ was x=0.07. After a small quantity of sulfur was introduced into the system, the luminescence intensity of phosphors was obviously enhanced. The reasons for the enhancement of luminescence are due to improved crystallization after S doping and the relatively large electronegativity difference between S and Mo. Additionally, the coincidence of the excitation wavelength with the emission of GaN chips may recommend this phosphor system as a potential candidate for use in white light-emitting diodes.