Upconversion Luminescence Properties of Y2Mo4O15: Yb3+, Er3+ by Solid State Combustion Method

The Yb3+ and Er3+ co-doped yttrium molybdenum oxide upconversion phosphors were prepared by the solid state combustion method using urea as fuel at ignition temperature of 550 °C. The upconversion phosphors were characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), and photoluminescence spectra. XRD results revealed the samples were pure monoclinic Y2Mo4O15 phases when the sintering temperature was 700 °C. SEM micrographs illustrated particle size distribution was almost uniform with an average particle diameter of about 0.5–1.0 m. The obtained Y2Mo4O15:Yb3+, Er3+ presents bright and pure green upconversion luminescence during daylight pumping under 980 nm LD. According to the analysis of upconversion luminescent mechanism, the cross relaxation processes of Er3+ ions restrained the electron population of red emission energy level, which not only increased the green light upconversion emissions fluorescent branching ratio (IG:IR = 153:1) but also enhanced the efficiency and purity of green light emissions.