Preparation and luminescence properties of Y 2 O 3 :Er 3+ /TiO 2 with high specific surface area

The three composites Y 2 O 3 :Er 3+ , Y 2 O 3 :Er 3+ /Yb 3+ and Y 2 O 3 :Er 3+ /TiO 2 were prepared using coprecipitation and sol-gel techniques. Their morphology, specific surface area, porosity, UV-vis. absorption spectra and fluorescence spectra were measured using SEM, TEM, surface analysis, UV-vis. absorption and photoluminescence spectrophotometry. SEM and TEM showed that samples prepared using coprecipitation were dispersed, while Y 2 O 3 :Er 3+ /TiO 2 particles possessed a mesoporous surface and average diameter of about 10 nm. The specific surface area and porosity of Y 2 O 3 :Er 3+ /TiO 2 did not result from the combination of the individual properties of Y 2 O 3 :Er 3+ and TiO 2 . The specific surface area of Y 2 O 3 :Er 3+ /TiO 2 was 135.991 m 2 /g and was 4.8 times that of Y 2 O 3 :Er 3+ and 2.5 times that of Degussa P25 TiO 2 . A high specific surface area is conducive for application to TiO 2 photocatalysis. The fluorescence spectra of the three composites exhibited three upconversion emission peaks with maxima at 237, 395 and 467 nm following excitation at 388, 500 and 570 nm, respectively.