Investigation On Growth And Upconversion White-Light Property Of Tm³⁺/Er³+)/Yb³⁺:C12A7 Single Crystal

12CaO·7Al₂O₃?short for C12A7?have potential application value in optical material owing to the outstanding properties of light transmission,heat stability and insulativity.The main theme of this thesis contains the preparation C12A7 single crystal that given upconversion white-light property and analysis of upconversion white-light mechanism.After that,C12A7 was characterized by XRD,IR and Raman spectrum.Finaly,to achieve a better performance in temperature sensor,the temperature sensitivity coefficients have been measured between the temperature range of 323K-623 K.First of all,the process parameters of C12A7 single crystal growth via Czochralski method have been studied.After continuously modulation of technology parameters,the optimum parameters have been found out.Next,the factor that causes the crack on crystal surface has been studied via XRD,Raman spectra and IR-visible absorption spectra,which indicates that C12A7: OH-was formed on the crystal surface.The rare earth concentration with upconversion white-light is settled down via a series of C12A7 polycrystal with different rare earth concentration.For the dephlegmation in crystal growth process,the concentration of doped rare earth ion has to be adjusted via CIE analysis.Finally,the Er³⁺ ion have to be cut down to achieve upconversion white-light,and single crystal that achieves upconversion white-light has been synthesized.The dependence of upconversion emission intensities on pump powers,decay dynamics of upconversion emission and steady rate equations are used to analyze upconversion white-light mechanism.The result shows that three-photon processes are involved to generate the upconversion blue emission and two-photon processes are involved to generate the upconversion green and red emission.However,the slope of blue upconversion emission is 2.4 which is a little lower than 3,owing to the cross relaxation between Tm³⁺ and Er³⁺ ion.The effect that temperature have on upconversion emission has been studied.At the temperature range of 323K-623 K,the FIR fitting was used to temperature coupling states of Tm³⁺ and Er³⁺ ion,the temperature sensitivity coefficient of Tm³⁺ and Er³⁺ ion are 555.07/T²,436.70/T²,respectively.