Synthesis And Properties Of The Tetraphenylethylene Derivatives Based Luminescent Lanthanide Nanomaterials

Rare earth elements are widely used in various new luminescent materials due to their unique fluorescent properties and excellent chelating ability.Using the energy transfer between organic molecules and rare earth elements to improve the luminescent properties of these elements has always been the focus of research in the field of optical materials.Tetraphenylethylene(TPE)and its derivatives are a class of typical organic fluorescent molecules with aggregation induced emission(AIE)properties,which can be combined with rare earth nanomaterials.On the one hand.TPE derivatives can be used as sensitizers to regulate the luminescence of rare earth elements;On the other hand,rigid inorganic rare earth nanomaterials can also control their AIE properties by limiting the intramolecular movement of TPE derivatives.This kind of TPE derivative/rare earth nano particle composite has important research significance and broad application prospect.In this paper,we designed and synthesized two kinds of TPE derivative modified rare earth nanocomposites.The intramolecular movement of TPE derivative was adjusted by surface loading,and then the fluorescence properties of the nanocomposites were regulated by the energy transfer process between TPE derivative and rare earth.The details are as follows:In the second chapter,we explored a method to regulate the intramolecular movement of TPE derivative by chelating it on the surface of inorganic rare earth nanomaterials.Carboxyl modified TPE derivatives and organic phosphonic acids with multiple coordination groups were immobilized on the surface of gadolinium phosphate nanorods.On the surface of the composites,organic phosphonic acid diethylene triamine pentamethylene phosphonic acid(DTPMP)successfully limits the intramolecular movement of TPE derivatives due to its large steric hindrance,which makes the radiation channel of TPE derivatives open successfully and presents significant fluorescence emission.Furthermore,in the presence of different ions,we used the difference of binding ability between organic phosphonic acid and different ions to study the fluorescence properties,in which Cu2+ ions can combine with the loaded DTPMP to remove the restriction of intramolecular movement of TPE derivatives on the surface of the material,resulting in fluorescence quenching,so as to realize the recognition of Cu2+.In the third chapter,the TPE derivative modified polyvinyl alcohol(PVA)was loaded on the surface of rare earth nanoparticles by coordination,and the TPE derivative/rare earth nanoparticles composite(TPEBA-Ln,Ln=Gd3+/Tb3+/Eu3+)was synthesized.The luminescent properties of the complexes were studied,which proved that there is an energy transfer process between TPE derivatives and rare earth elements in the system.The ternary fluorescence system of "TPE derivative/terbium/europium"was constructed by co-doping terbium/europium in the matrix of rare earth particles.The white light emission was successfully adjusted by controlling the ratio of Tb3+/Eu3+co-doping and the amount of ligand.Further studies on the optical properties show that these materials have different fluorescence responses in the presence of PVA with different molecular weights.