Study On The Performence Of Rare Earth Doped Fluoride Upconversion Thin Film

Rare-earth(Re) doped upconversion(UC) materials have very wide applications, including lasers, storage, solar-cell, and so on. Due to their excellent optical properties, Re doped fluoride UC materials have become a hot research point. Re doped fluoride UC thin films could overcome the shortcomings of bulk and power materials, thus greatly improving the availability of the Re doped fluoride UC materials. The main contents in this thesis are as follows:(1) Synthesizing Yb3+ and Tm3+ ions codoped NaYF4 bulk materials as the coating material by high temperature solid state reaction, and the as-synthesized coating material can emit bright blue UC fluorescence under 980 nm excitation.(2) Yb3+ and Tm3+ ions codoped NaYF4 thin film, about 1μm thick, has been deposited on an Al2O3 plate by traditional vacuum thermal evaporation deposition technology through the way of resistance heating. The as-prepared thin film can emit bright blue UC fluorescence under 980nm excitation. Recorded the film's UC spectra by a fluorescence spectrophotometer, characterized its structure and morphology through X-ray diffraction and scanning electron microscopy, respectively.(3) Compared two different Yb3+ and Tm3+ ions codoped NaYF4 thin films'UC spectra under same power 980 nm excitation. The films were prepared with the synthesized coating material and the unsintered powder mixture with the same ratio, respectively.(4) Studied annealing process's effect on the UC performance, structure and morphology of the Yb3+ and Tm3+ ions codoped NaYF4 thin films.(5) Synthesized different NaYF4:Yb3+, Tm3+ and TiO2 composite films, discussed the effect on NaYF4:Yb3+, Tm3+ thin film's UC performance, structure and morphology from TiO2 film, which has both NIR reflectance and UV absorption properties.(6) Synthesized NaYF4:Yb3+, Er3+ thin film with the process compared to NaYF4:Yb3+ Tm3+ thin film, characterized its structure, morphology and UC spectra, and studied the effect of annealing process on the film's structure and UC performance.