Photoluminescence Characteristics Of Rare Earth(Tm³⁺,Er³⁺,Yb³⁺) Codoped

The materials doped rare earth play an important role for the application on lighting, environment, health care, energy source, military, aerospace, and so on, and it becomes the attentive focus.The crystal strcture and the photoluminescence characteristics of the samples that TiO2is taken as matrix and the trivalent elements of rare earth Tm、Er and Yb are only doped or codoped are discssued at the thesis. The main works are as follows:1. The samples of the TiO2powdere doped Tm3+only, Tm3+/Yb3+codoped and Er3+/Yb3+copoed, respectively, have been were preparaed using the water-borne sol-gel technique. The effect on crystal structure of the sintering temperature and dopant concentration is analysed with the aid of the X-ray diffraction spectra. The XRD spectra of Tm3+/Yb3+doped TiO2powders sinteringed at the same temperature show that it is no evidence impact on the crystle strucure of the TiO2when rare earth ions are implanted into the matrix. The TiO2phase structure is mixed phase of y-TiO2and a-TiO2mainly.2. The excitation spectra and emission spectra of the Tm3+doped and Tm3+/Yb3+codoped TiO2powders are measured, respectively. The optimal excitation wavelength is550nm while the character emission at665nm of Tm3+ions is monitored. At the same time, the excitation spectra at222nm of TiO2oneself is also observed. The emission spectra of Tm3+ions at478nm (blue),650and693nm (red),800and830nm (infrared) are obtained by the excitation at365and488nm, respectively. The influence of different Tm3+and Yb3+dopant concentrations on the excitation intensities and emission intensities is discussed. The results show that Yb3+ions are ideal sensitizer for Tm3+ions to enhance its photoluminescence intensity.3. The up-conversion mechanisms of Tm3+/Yb3+codoped and Er3+/Yb3+codoped TiO2powder samples are investigatied. The up-conversion emissions of the Er3+/Yb3+codoped TiO2powders at516,538,648,663and830nm are measured. The up-conversion intensities are clearly enhanced because of Yb3+doping, and optimal concentration of Er3+and Yb3+are0.3and10mol%, respectively. The optimal concentration of Tm3+and Yb3+are0.1and10mol%. The Yb3+ion also plays sensitive function for Tm3+ions4. The up-conversion photoluminescence spectra of the Tm3+/Er3+/Yb3+codoped titanium dioxide powders are analyzed. The action of Tm3+ion on the photoluminescence intensity of Er+/Yb3+is discussed emphatically. And, the relationship between the photoluminescence intensity and pump power investigated. It is approved that red emission of Tm3+/Er3+/Yb3+codoped TiO2is two-phonon process.