Study On The Preparation And Optical And Catalytic Properties Of Composite Structure Of Er³⁺-Yb³⁺:NaYF₄ And Metal Oxide

Upconversion luminescent materials have a wide range of applications in the fields of biomedicine,infrared anti-counterfeiting.As a matrix,NaYF₄ has been widely studied in the field of upconversion luminescence because of its low phonon energy,good chemical stability and excellent optical properties.The semiconductor metal oxide also has important research significance in the field of upconversion luminescence,some semiconductor metal oxides play an important role in the field of photocatalysis.Combined semiconductor metal oxide with NaYF₄:Yb₃₊,Er³⁺ nanocrystals and studied their luminescent properties and catalytic properties,it will provide a new idea for the application of photocatalytic and optoelectronic devices.The main research contents are as follows.?1?NaYF₄:Yb₃₊,Er³⁺ nanocrystals were synthesized by solvothermal heat or high temperature pyrolysis.It is two phase structures of cubic and hexagonal have been synthesized by using XRD to characterize.Discussed the luminescence mechanism of NaYF₄:Yb₃₊,Er³⁺ nanocrystals from spectral analysis,it suggested that the luminescence centers of NaYF₄:Yb₃₊,Er³⁺ nanocrystals are located in 520 nm,540 nm and 654 nm respectively and a two-photon process was involved in upconversion luminescence.?2?Synthesized NaYF₄:Yb₃₊,Er³⁺/ZnO composite nanofibers by calcining composite at different temperature.which used the method of electrostatic spinning combined NaYF₄:Yb₃₊,Er³⁺ nanocrystals with Zn?CH₃COOH?₂ · 2H₂O.With the increasing of calcining temperature,the upconversion luminescence intensity of NaYF₄:Yb₃₊,Er³⁺/ZnO composite nanofibers are also increased.Temperature sensing test for NaYF₄:Yb₃₊,Er³⁺/ZnO composite nanofibers suggest that NaYF₄:Yb₃₊,Er³⁺/ZnO composite nanofibers are more sensitive to temperature and more adaptable to the temperature range.?3?W₁₈O₄₉ nanowires were prepared by solvothermal method,it has strong absorption in the visible near infrared because of a large number of oxygen vacancies on its surface.NaYF₄:Yb₃₊,Er³⁺/W₁₈O₄₉/FTO composite nanofilm was prepared by combining the NaYF₄:Yb₃₊,Er³⁺ nanocrystals and W₁₈O₄₉ nanofilm.Excitation composite nanofilms by a laser with a wavelength of 980 nm,we found the green upconversion luminescence strength of the composite nanofilm is significantly higher than that of NaYF₄:Yb₃₊,Er³⁺ crystal.?4?Design and synthesis of catalyst NaYF₄:Yb₃₊,Er³⁺@W₁₈O₄₉ heterostructure driven by near infrared light,use a laser with a wavelength of 980 nm as a excitation light source,at the same time,NaYF₄:Yb₃₊,Er³⁺@W₁₈O₄₉ heterostructure,has a stronger ability than W₁₈O₄₉ nanowires on catalyzing decomposition of ammonia borane for hydrogen production.It suggests that NaYF₄:Yb₃₊,Er³⁺@W₁₈O₄₉heterostructure is a good Photocatalyst.