Structural and excitation dependent emission properties of octahedral CeO2:Er3+ nanocrystal

Abstract Octahedral CeO 2 :Er 3+ nanocrystals were successfully prepared using a simple hydrothermal method, and the structural and excitation dependent emission properties were investigated in detail. Green ( 2 H 11/2 , 4 S 3/2  →  4 I 15/2 ), red ( 4 F 9/2  →  4 I 15/2 ) and NIR ( 4 I 11/2  →  4 I 15/2 and 4 I 13/2  →  4 I 15/2 ) emission were observed under 980 nm laser diode excitation. The optimal Er 3+ doping concentration was 3 mol%, and the effect of Li + co-dopants with concentration up to 10 mol% on microstructure and emission was investigated. However, for the samples excited under 352 nm down-conversion excitation, the Vis-NIR spectral distribution induced distinct changes related to the excitation mode. Remarkably high enhancement of 1532 nm NIR emission about 12 times was achieved by codoping with Li + ions, which make CeO 2 :Er 3+ ,Li + nanocrystal a promising candidate for optical amplifier using broadband UV pumping. The possible mechanism of above up-and down-conversion emission and energy transfer process has also been discussed.