Up-conversion Luminescence Of Rare-earth Doped TiO₂ Nanocrystallite Excited By 980nm

China rareearth industry plays an important role in the world because of its abundant inrareearthdeposits. Recently, with the development of separation and purification technique,It has been made great progress on the research and application of rareearthfunctionalmaterial, especially rareearthupconversionmaterial. The upconversionis a special propertyof rare earth ion. The selection of suitable matrix in order to obtaining high luminescenceefficiency is a hot spot in this field.It is the aim to find a suitable oxide as a doped matrix for rareearthions to get a highupconversionefficiency. The upconversionluminescence propties of rareearthions werediscussed under a 980nm LD excitation under different concentrations, annealed temperaturesand measured temperatures in TiO₂ nanocrystals matrix. The upconversionmechanisms ofthe Er³⁺ /Yb³⁺ and Tm³⁺/Yb³⁺ codopedTiO₂ were investigated. The results as bellow:1. Green and red emission at 525nm,550nm and 660nm were obtained in Er³⁺/Yb³⁺ codopedTiO₂ Nanocrystallite. Blue and red emission at 476nm and 650nm were obtained inTm³⁺/Yb³⁺ codopedTiO₂ Nanocrystallite. The phase and size of TiO₂ nanocrystals werechanged after doping rareearth.2. Because of the special energy level of Yb³⁺, it can sensitize Er³⁺ and Tm³⁺. Theluminescence intensity in Er³⁺/Yb³⁺and Tm³⁺/Yb³⁺ codopedTiO₂ sample are much strongerthan that without Yb³⁺ ions.3. The luminescence intensities increase with the increasing annealed temperatures.4. The luminescence intensities increase with the increasing of rare earth ions concentration.When the concentration of Er³⁺ or Yb³⁺ ions reaches to 15mol%, the luminescence intensitiesdecrease as the increasing of another ion concentration. The same result is obtained when theconcentration of Tm³⁺ is 0.2mol% while of Yb³⁺ ion is 2mol%.5. Increasing excited power can augment the upconversion luminescence obviously but theshape of emission spectra not change.6. Under different excited temperatures, the upconversion luminescence emission spectra ofthe rare earth codopedTiO₂ sample are resembled. The luminescence intensities decreasewith the increasing temperature.7. According to the relation between the upconversion intensities and the power pump, theupconversion luminescences mechanism both of Er³⁺/Yb³⁺ and Tm³⁺/Yb³⁺ in TiO₂nanocrystals are attributed to twophotonabsorption upconversionprocess.