Tunable PL characteristics and energy transfer in Gd2O3:Eu3+, Bi3+ nanophosphors

Red emitting nano phosphors with the compositions of Gd2O3:Eu3+ (4 mol%), Bi3+ (Bi3+ = 0, 1, 3, 7, 9, 11 mol%) were synthesized by low-temperature solution combustion method in a short time (less than 5 minutes). The powders were calcined at 800°C were characterized by PXRD confirm the calcined product was monoclinic phase. The particle size was estimated using Scherrer's and W-H Plots and found to be in the range 40-60 nm. It is observed that a significant quenching of Eu3+ emission was observed under 230 nm excitation when Bi3+ (0, 1, 3, 7, 9, 11 mol %) was co-doped. The introduction of Bi3+ ions broadened the excitation band of Eu3+ emission of which a new strong band occurred ranging from 320-380 nm due to the 6s2 → 6s6p transition of Bi3+ ions, implying a very efficient energy transfer from Bi3+ ions to Eu3+ ions. These results show that the Bi3+ co-doped Gd2O3:Eu3+ phosphors have promising applications in solid state lighting in the future. (author)