Blue, green, red upconversion luminescence and optical characteristics of rare earth doped rare earth oxide and oxysulfide

The cold isostatic press pretreatment process was adopted to prepare fine rare earth oxysulfide upconversion phosphors with spherical shape, narrow size distribution and high luminescence efficiency. The upconversion optical characteristics and brightness of the blue (Y2O2S:Yb,Tm), green (Y2O2S: Yb,Er), red (Y2O3: Yb,Er) emitter were also investigated, and a novel method was successfully developed for the brightness measurement of upconversion luminescence (UPL). It is shown that a white color can be obtained by the appropriate mixture of these primary blue, green and red emissions components. The Er3+ ions exhibit different upconversion mechanism in Y2O2S and Y2O3 host materials. The rare earth oxysulfide is an efficient upconversion matrix. The UPL brightness of Y2O2S:Yb,Er is 6.5 times higher than that of Y2O3: Yb,Er, and Y2O2S: Yb,Er shows UPL brightness of 1100 cd/m(2) under 5.56 W/cm(2) power density using a 980 nm laser diode.