Intense white light emission in Tm3+/Er3+/Yb3+ co-doped Y2O3-ZnO nano-composite

The Tm3+/Er3+/Yb3+ co-doped Y2O3-ZnO nano-composite is synthesized using the solution combustion technique. The structural morphology is monitored using x-ray diffraction, transmission electron microscopy and scanning electron microscopy. The Yb3+/Tm3+ co-doped nano-phosphor emits intense blue as well as weak red emissions, while Yb3+/Er3+ co-doped nano-phosphor emits strong green along with red emissions on excitation with 976 nm laser. Joining these together (i.e. Tm3+/Er3+/Yb3+ co-doped phosphor) give very strong white light, which is further verified by CIE coordinates (0.32, 0.36). The addition of ZnO with Y2O3 phosphor gives further enhancement in the intensity of white light. The possible reason for this enhancement is the removal of optical quenching sites.