Study On Upconversion Luminescence Modulation And Luminescence Properties Of Indium Oxide And Scandate Nanocrystals

In recent years,upconversion luminescent(UCL)materials have attracted the widespread attention of researchers for their unique luminescent properties,and have been widely used in display lighting,medical imaging and solar cells.The disadvantages of low upconversion efficiency and weak luminescent intensity are often overcame by selecting excellent host materials,because of the host materials of UCL have a great influence on the overall luminescent properties.At present,more and more oxides with low phonon energy have been developed,and oxides have been widely used.In this paper,In₂O₃ and Ca_xSr_1-xSc₂O₄ are used as matrix materials,the upconversion luminescence properties and mechanism of Yb³⁺/Er³⁺,Yb³⁺/Ho³⁺and Yb³⁺/Tm³⁺in In2O3materials are systematically studied,and the peculiar spectral changes in Ca_xSr_1-xSc₂O₄:Yb,Er are found.The specific research contents and results are as follows:(1)Monodisperse In₂O₃:Yb,Ln(Ln=Er,Ho,Tm)nanocrystals with an average particle size of 31 nm were be successfully synthesized by solvothermal method in a three-neck flask.Compared with literature reports,the red light intensity and green light intensity of the nanocrystals are increased by 1.85 times and 1.55 times,respectively.Fourier transform infrared spectroscopy(FTIR)shows that the enhancement of UCL intensity can be attributed to the increase of surface groups.Simultaneously,the possible energy transfer process of In₂O₃:Yb,Ln(Ln=Er,Ho,Tm)NPs have also been investigated by the spectra distribution and power dependence.Since indium oxide is easy to deliquescence in air,this experiment also coated it with SiO₂ shell.It can be seen from the emission spectrum after 60 days that the coated SiO₂ can effectively alleviate the deliquescence of In₂O₃.(2)A series of Ca_xSr_1-xSc₂O₄:Yb,Er(x=1,0.8,0.6,0.4,0.2,0)nanocrystals were successfully prepared by hydrothermal method and characterized by X-ray diffraction(XRD),fluorescence and Raman spectra.From the excitation spectrum,it can be seen that with the increasing of Sr³⁺concentration,the red part of the material changes obviously.This phenomenon is attributed to the change of the crystal field.Simultaneously,the possible energy transfer process of Ca_xSr_1-xSc₂O₄:Yb,Er nanocrystals have also been investigated.