Design And Synthesis Of Fluorescent MOFs And Their Application In White Light

As a promising lighting source,solid-state white light-emitting diodes(WLEDs)have attracted much attention because of their environmental friendliness,performance savings,long life,and high efficiency.Therefore,due to the wide application in display devices,obtaining white light emission from ultraviolet excitation is an important area of light emission research.Among many materials for preparing white light emission,light-emitting metal-organic framework materials(MOFs)are widely used in fluorescent probe sensing due to their adjustable structure,rich light-emitting sites,and rich energy transfer in the structure.,Biological imaging,lighting display and other fields.In this paper,based on the design and synthesis of luminescent MOFs,we explored the method of replacing metal ion nodes in lanthanide MOFs to prepare lanthanide mixed metal single-phase white light materials,MOFs composite inorganic white light materials,and MOFs porous materials absorb fluorescent dyes to modulate white light Launch,and the application of the synthesized MOFs composite materials in metal identification.This article is mainly divided into the following three contents:A series of new lanthanide complex materials Ln-dbpt(dbpt=3-(3,5-dicarboxyphenyl)-5-(pyrazinyl)-1H-1,2,4-tris were synthesized by hydrothermal method Azole,Ln=Eu,Tb,La).The synthesis method and crystal structure were discussed in detail,and the XRD,thermogravimetric and infrared tests confirmed that the material had good stability.Based on the systematic exploration of Ln-dbpt's own luminous performance,the key point is to explore the method of preparing single-phase complex materials with different luminous effects by replacing the nodes in the metal center to obtain the three-metal white light material La_0.928Eu_0.045Tb_0.027-dbpt,double Metal white light materials La_0.896Eu_0.104-dbpt and Eu_0.026Tb_0.974-dbpt.The quantum yields of the three materials reached 8.7%,8.18%and 8.84%.During the research,it was found that due to the weak blue light emission of La-dbpt,the amount of white light materials used was huge.In order to reduce the cost and improve the luminous performance of the composite material,the g-C₃N₄material with simple preparation and better luminous performance is used to replace the weak blue light emitting material La-dbpt to prepare a mixed white light material(g-C₃N₄)_0.783/Eu_0.133/Tb_0.083-dbpt,its quantum yield is11.7%,relative to the lanthanide complex white light material cost reduction and performance has been improved to a certain extent.Three structurally similar tetraacid ligands 2,5-bis(3',5'-dicarboxyphenyl)pyridine(H₄L¹),2,5-bis(3,5-dicarboxyphenyl)isonicotinic acid(H₄L²),5,5'-(anthracene-9,10-diyl)diisophthalic acid(H₄L³)as an organic linker,indium ions as a metal center,and three cases of three-dimensional porous structures with similar structures were synthesized by hydrothermal The materials In-L¹,In-L²,In-L³ have a porosity of 65%to67%.Therefore,we selected cationic Rh6G and BPEA dyes for dimming experiments to prepare two white light materials Rh6G/BPEA@In-Lⁿ(n=1,2).Because the pore size of the complexes limited the dye adsorption effect,we also selected AF and Rh6G dyes to prepare three white-light materials Rh6G/AF@In-Lⁿ(n=1,2,3).In addition,we also prepared three kinds of white light materials In-Lⁿ-Rh6G&BPEA(n=1,2,3)by in-situ loading.For the 8 kinds of white light materials prepared,it can be found that the performance of the In-L1 series white light materials is relatively superior.The material with the best effect,Rh6G/AF@In-L¹,has a quantum yield of24.8%and a color rendering index of 81.6,the correlated color temperature is6961 K,which shows better luminous performance.At the same time,in order to solve the problem of the poor luminous effect of the composite material due to the luminous performance of the complex material itself and the energy loss between the host and the guest.We use the method of preparing yellow light phosphors and blue light chips to prepare white light devices.Among them,the best yellow-light phosphor In-L²-Rh6G&BPEA has a quantum yield of 35.3%and a light efficiency of 66.68 lm/W.It exhibits high luminous performance and is more suitable for systems that are equipped with blue light chips to form white light devices.We choose the three homogeneous complex materials In-L¹,In-L²,and In-L³ in Chapter 3 and five single-phase white light materials Rh6G/AF@In-Lⁿ(n=1,2,3),Rh6G/BPEA@In-Lⁿ(n=1,2)for metal ion recognition performance.In-L¹ material has better fluorescence enhancement effect on Al³⁺,In-L² shows better single metal recognition effect on Fe³⁺;and In-L³ shows excellent recognition effect on selected trivalent metal ions.The three homologous complexes showed completely different three recognition properties.Compared with pure complex materials,the fluorescence of white light composite materials exhibits multiple peaks,so the intensity of different wavelengths can be used to more accurately identify metal ions.And the recognition performance of In-L¹ series white light materials for metal ions is improved compared to the complex materials,and the recognition performance of white light materials prepared by adsorbing different dyes has certain differences;in the In-L² series,three materials Both of them show good recognition effect on Fe³⁺,and the composite white light material Rh6G/AF@In-L² can accurately detect Cu²⁺through the ratio of double peaks.For the In-L³ series of known complex materials,which have a good recognition effect on trivalent metal ions,the composite white light material In-L³@Rh6G/AF prepared by the introduction of guest molecules can achieve a single recognition effect on Fe³⁺.