Construction And Properties Of Rare Earth Doped Bi-MOF And Tungstate Tungsten Based Fluorescence Sensing Systems

Rare earth doped luminescent materials have been used in sensing,biomedical,catalysis,military and other fields due to the unique electronic layer structure of rare earth elements and excellent physical properties such as photoelectromagnetism.In recent years,rare earth doped metal organic frameworks and upconversion materials have been used as optical sensors,which can be conveniently and quickly used as optical probes for cations,anions,small organic molecules,pH,temperature,etc.The design of this thesis is mainly based on the construction and sensing performance of rare earth doped metal organic framework and upconversion material fluorescence system.(1)A series of Eu3+/Tb3+single-doped or co-doped rare earth functionalized Bi-MOF materials were prepared by in-situ solvothermal conditions using BiOBr nanosheets as Bi source of Bi-MOF materials.By modulating the different doping amounts of rare earths,white light emission based on red-green-blue primary color modulation can be finely realized.In addition.Eu3+/Tb3+ single-doped Bi-MOF materials can also be used as multifunctional fluorescent probes for Fe3+,Cr2O72-ion and acetone molecules in aqueous solution,and the possible sensing mechanism of the materials is analyzed.These lanthanide ion-functionalized Bi-MOF materials have great potential for exploring white light-emitting devices and building ultra-sensitive materials.(2)A novel up-conversion(UC)fluorescent sensing material with g-C3N4 doped BaWO4:Yb3+,Er3+ was prepared by solvent-free thermal and crystalline cutting methods.Compared with BaWO4:Yb3+,Er3+,g-C3N4/BaWO4:Yb3+,Er3+composites exhibit enhanced UC emission under near-infrared(NIR)light at 980 nm,which is attributed to the energy-level assistance of g-C3N4,which can be attributed to Effectively capture the energy of non-radiative transitions from the higher excitation energy level[2F7/2,1B(1T2)]to the lower excitation energy level[2F7/2,1E(1T2)]in the[Yb3+-WO42-]system.This composite with enhanced UC luminescence can be used in the field of self-calibrating and highly sensitive optical thermometers.The results show that g-C3N4 doped BaWO4:Yb3+,Er3+ composites can be used as optical thermometers.