Hydrothermal Synthesis And Optical Property Optimization Of Y?Lu?₆O₅F₈ Nanomaterials

In recent years,upconversion micro/nano materials have attracted more and more attention due to their potential applications in color display backlights,bio-imaging and photodynamic therapy,etc.The up-conversion material is a kind of material that can convert near-infrared light into ultraviolet or visible light.Lanthanide ions can be used as ideal dopant ions due to their abundant energy levels and narrow emission lines from internal 4f-4f conversion.Combined with the low phonon energy of fluoride and the high mechanical properties and good chemical stability of oxides,the oxyfluoride system is a fluorescent doping system worthy of study.Under the excitation of near-infrared light,the Er³⁺ions in the host lattice can emit blue light(²H_9/2?⁴I_15/2),green light(²H_11/2,⁴S_3/2?⁴I_15/2),and red light(⁴F_9/2?⁴I_15/2).As a sensitizer ion,Yb³⁺can absorb near-infrared light of 980 nm and transfer it to Er³⁺through energy conversion to enhance luminescence.In this thesis,the two kinds of oxyfluoride materials are system prepared and their optical properties are mainly studied.The main contents are as follows:Yb³⁺,Er³⁺,Fe³⁺co-doped Y₆O₅F₈ and Yb³⁺,Er³⁺,Mo⁶⁺?V⁵⁺co-doped Lu₆O₅F₈matrix upconversion phosphors were prepared by hydrothermal method.The products were characterized by XRD,XPS,SEM,TEM,UCL etc.analytical methods.In the experiment,the value of pH,doping ions and their concentrations were controlled during the reaction.The products showed different morphologies,different luminescent intensity and color display.Combined with the reaction conditions,we performed the spectral performance test and thermal quenching performance test on typical samples,furthermore,we made a sufficient theoretical analysis and reasonable explanation for these results.The introduction of Fe³⁺resulted in a significant increase in the emission intensity of typical sample at 671nm.The temperature-dependent emission spectrum exhibits a significant thermal coupling between the ²H_11/2 and ⁴S_3/2 levels of Er³⁺.Based on this excellent temperature response,we explored the application of this material in temperature-sensitive sensors.For the excellent luminescence properties and magnetic properties of the samples,the application of our materials in anti-counterfeiting and targeted therapy was initially explored.The introduction of Mo⁶⁺and V⁵⁺can significantly affect the luminescence of Er³⁺.Spectral tests at different excitation light source power for the best V⁵⁺concentrated samples show that the spectral red and green components have different changes with the increase of excitation power.Based on this phenomenon,we have made a reasonable explanation for its luminescence mechanism.