Upconversion properties of Y 2O 3:Er films prepared by sol-gel method

Abstract

Y 2O 3:Er 3+ films were prepared by a simple sol-gel process. The structural properties of Y 2O 3:Er 3+ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The results indicated that the Y 2O 3:Er 3+ films might have high upconversion efficiency because of their low vibrational energy. Under 785 and 980 nm laser excitation, the samples showed green ( 2H 11/2→ 4I 15/2, 4S 3/2→ 4I 15/2) and red ( 4F 9/2→ 4I 15/2) upconversion emissions. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The cross relaxation process in Er 3+ was also investigated.