Effect of Y3+ on the photoluminescence of MgAl2O4:Cr3+ nanopowders

The Pechini-type hydrothermal process was used to prepare Y3+ doped MgAl2O4: Cr3+ nanopowders. The effect of Y3+ on the structure, crystal field, and photoluminescence of MgAl2O4: Cr3+ was considered. The single phase of MgAl2O4 was obtained at the calcination temperature of 900–1200 °C. As the calcination temperature reached 1300 °C, the impurity phases Y3Al5O12 appeared, along with a trace of MgO. When Y3+ content was more than 3 mol%, Y3Al5O12 and MgO phase also existed. The Y3+ ions doped MgAl2O4: Cr3+ enhanced the photoluminescence of samples, and the emission of sample Y3 was 80% higher than that of Y0. Meanwhile, the Y3+ ions affected the position of absorption and excitation spectra and caused the change of crystal field surrounding Cr3+. The strongest absorption and excited bands shifted to longer wavelengths, and the 4A2-4A1 absorption of Cr3+ was enhanced. The Dq/B value of sample Y0 was 3.33, and it increased slightly as Y3+ doped. The Dq/B value of sample Y3 was 3.46. As an excellent sintering aid for the sintering process of MgAl2O4 transparent ceramics, Y2O3 is also helpful to enhance the photoluminescence of MgAl2O4: Cr3+.