Blue and green emission from Ce3+ and Tb3+ co-doped Y2O3 nanoparticles

Tb3+ doped Y2O3 nanoparticles of 4-10 nm size were synthesized from nitrate precursors by the urea hydrolysis method in ethylene glycol medium at a low temperature of 140 °C. Characteristic green emission of Tb3+ corresponding to 5D4→7FJ is observed to be very strong, which is further enhanced with heat treatment temperature. Characteristic blue color emission of Ce3+ ion originating from 5d→2F7/2 (424 nm) and 2F5/2 (486 nm) transitions are found to be very strong in as-synthesized Ce0.02Tb0.06Y1.92O3 nanoparticles. However, its luminescence intensity decreases with increase in heating temperature or increase in the particle size/crystallinity, whereas a weak emission peak of Tb3+ ion at 545 nm is witnessed. The polycrystalline nature of the as-prepared sample changed to highly crystalline state when heated at an elevated temperature (1200 °C).