Enhanced white light emission in Er/Tm/Yb/Li codoped Y2O3 nanocrystals

Er/Tm/Yb codoped Y2O3 nanocrystals and Er/Tm/Yb/Li codoped Y2O3 nanocrystals have been synthesized by sol-gel method, bright white light emission has been observed at 976 nm excitation. The blue, green, and red emissions, respectively, arise from the transitions (1)G(4) -> H-3(6) of Tm3+, H-2(11/2)/S-4(3/2) -> I-4(15/2), and F-4(9/2) -> I-4(15/2) of Er3+ ion. Moreover, after doping Li+ ions into Er/Tm/Yb codoped Y2O3 nanocrystals, the white light emission increase greatly. CIE coordinate of Er/Tm/Yb/Li codoped Y2O3 nanocrystals is X = 0.32 and Y = 0.36 at 10 W/cm(2) excitation, which is very close to the standard equal energy white light illuminate (X = 0.33, Y = 0.33). (C) 2009 Elsevier B.V. All rights reserved.