Red luminescence of Lu2O2S:Ce and Y2O2S:Ce at room temperature

Lu2O2S:Ce (8.90 g/cm3) and Y2O2S:Ce (4.92 g/cm3) powder crystals have been prepared by oxalate co-precipitation first and then solid state reaction at 1150 °C in reducing atmosphere. X-ray diffraction (XRD) patterns show that they are of hexagonal structures. Photoluminescence (PL) of them is red and can be observed at room temperature. The emission spectrum of Lu2O2S:Ce has one broad band peaking at 650 nm; Y2O2S:Ce has two peaking at 346 and 600 nm. Gaussian components of these peaks suggest that they originate from the 5d–4f transition of Ce3+. Photoluminescence, photoluminescence excitation (PLE) and diffuse reflectance spectra of Lu2O2S:Ce and Y2O2S:Ce as well as their luminescent mechanism have been studied.