Preparation Of Fluorescent Nanoparticles And Their Application In Luminescent Fibers

Rare-earth elements have a special 4f electron configuration,imparting uncommon photonic properties.Studies on rare-earth-doped polymer-based light-emitting materials are of great interest,because they have played a pivotal role in the fields of medical diagnostics,displays,and detection systems.A novel anhydrous preparation of silica?SiO₂?-encapsulated terbium(Tb³⁺)complex nanoparticles has been investigated.In this paper,rare earth organic-inorganic complexes/polymer composites with good dispersibility and fluorescence properties were prepared by electrospinning and Hack rheometer.The relationship between the structure of the composites and the fluorescence properties of the composites was studied.The main work is listed as follow:The organic ligands Hacac and Phen with high ultraviolet absorption were introduced into terbium complexes,Tb?acac?₃phen complexes with high fluorescence properties and long lifetime were synthesized.The structure and fluorescence properties of rare earth complexes were characterized by TEM,FTIR and steady/transient fluorescence spectrometer.The effect of pH on the fluorescence of Tb³⁺complexes was discussed.The fluorescence intensity and fluorescence lifetime of rare earth complexes changed regularly with the change of pH.The strongest fluorescence and longest fluorescence lifetime were obtained when pH equals 9.A novel anhydrous preparation of silica?SiO₂?nanoparticles was prepared,and the SiO₂-Tb³⁺nanoparticles were synthesized by step method.Then we characterized the nanoparticles by TEM,HRTEM,FTIR,XRD,Steady/Transient state fluorescence spectrometer.The morphological and structural feature of the resulting samples were examined by TEM,from this,it is clear that SiO2 nanoparticles are uniform and nonagglomerated with monodisperse spheres.HRTEM Mapping showed that Tb?acac?₃phen was successfully introduced into SiO₂ nanosphers.XRD and FTIR were used to characterize the coordination modes and crystalline forms of rare earth complexes and SiO₂ nanospheres.The fluorescence spectra show that the fluorescence of Tb?acac?3phen is enhanced after it is encapsulated by SiO₂.The SiO₂-Tb³⁺nanoparticles are incorporated in electrospun polyvinylpyrrolidone hybrid nanofibers.Transmission electron microscopy?TEM?confirmed that Tb³⁺complexes were uniformly and stably encapsulated or carried by nano-silica.There is an increase in the fluorescence lifetime of SiO₂–Tb³⁺/polyvinylpyrrolidone?PVP?hybrid nanofibers compared with the pure Tb³⁺complexes.The SiO₂-Tb³⁺nanoparticles were successfully added into PMMA fibers by HAAKE torque rheometer.The fluorescent properties of PMMA fibers at different doping concentration were tested.The hot melting of composite fibers was measured by differential scanning calorimetry.The heating and cooling curves were obtained.After doping SiO₂-Tb³⁺nanoparticles,the glass transition temperature of PMMA increased,and the high temperature resistance of PMMA was improved.