Surface Modification Of NaY_0.8F₄:Yb³⁺_0.17,Er³⁺_0.03 And Synthesis Of It's Expoxy Nanocomposites

Upconversion nanoparticles (NPs) have been investigated extensively because of their potential applications in various fields, such as solid-state lasers, light emitting devices,biological labeling, and flatpanel displays. Upconversion NPs can absorb near-infrared light and they can convert near-infrared (NIR) photons to visible light by absorbing low-energy photons and then emitting high-energy photons. Upconverting fluorescence is compact,power-rich, the optical train is so simple that simultaneous detection of multiple analytes can be realized. NaY0.8F4: Yb3+0.17, Er3+0.03 were the most efficient near-infrared or infrared upconverting nanoparticles, but prone to quenching and poor biocompatibility. The structure of core/shell is an important strategy for avoiding quench the luminescence. Epoxy resin is one of the most widely used thermosetting resins. It's main communication window is in the visible region (570 nm, 650 nm and NIR region 780 um, respectively), which coincidence with the widely used optical communication window. So far, there were few reports about the research on NaY0.8F4:Yb3+0.17, Er3+0.03 expoxy polymer composites.SiO2 or TiO2 shells are generally grown on the surfaces of nanoparticales by cohydrolysis and polycondensation with tetraethyl orthosilicate (TEOS) or tetrabutyl titanate(TEOT), respectively. In order to obtain good dispersibility and luminous performance of composite materials. 3-aminopropyltriethoxysilane(KH-550) and Octoxinol(Triton X-100)were chosen as surfactant, the former have the amine group can react with expoxy resin, and the latter can enhance rare earth doped nanoparticles luminescent intensity.In this dissertation, Firstly, NaY0.8F4: Yb3+0.17, Er3+0.03 were synthesised in high temperature, non-aqueous solvents and oleate system. Secondly, the amount of TEOS or TEOT and the reaction time on the influence of the core-shell structure were studied. The result were showed as the following: 1) the NaY0.8F4: Yb3+0.17,Er3+0.03/SiO2 nanoparticles which with rounded shape and best luminous performance were prepared when added 300 ?L TEOS and reacted for 30 min; 2) when added 510 ?L TEOT and reacted for 45 min, the NaY0.8F4: Yb3+0.17, Er3+0.03/TiO2 nanoparticles were obtained which have rounded shape and best luminous performance; Thirdly,the core/shell NaY0.8F4: Yb3+0.17,Er3+0.03/SiO2(TiO2)produced which prepared under the best technology parameters, were modified by KH-550 or Triton X-100, the linkage groups of surfactant pointing outwards and adhered to the surfaces of the SiO2 or TiO2 shells. We got the product of different morphology and luminescent properties. The results were showed as the following: 1) the core/shell structure of NaY0.8F4:Yb3+0. 17, Er3+0.03/SiO2/KH-550 was regular, rounded shape and the luminous intensity were a certain enhanced compared with NaY0.8F4: Yb3+0.17,Er3+0.03 nanoparticles. 2) NaY0.8F4:Yb3+0.17, Er3+0.03/SiO2/Triton X-100 has ideal core/shell structure, but the luminous intensity were decreased in a certain extent; 3) the core/shell structure of NaY0.8F4: Yb3+ 0.17,Er3+0.03/TiO2/KH-550 were observed and the luminous intensity were increased greatly; 4) the structure of the obtained NaY0.8F4: Yb3+0.17,Er3+0.03/SiO2/Triton X-100 nanoparticles were irregular morphology, as well the luminous intensity were increased, and purple glow center appeared at 489 nm.At last, the product resulting from the modified of NaY0.8F4: Yb3+0.17, Er3+0.03/SiO2(TiO2)by KH-550 or Triton X-100 were used to prepare epoxy matrix composites, five kinds of epoxy resin nanocomposite with different morphology and luminescence properties were obtained. NaY0.8F4: Yb3+0.17, Er3+0.03/TiO2/KH-550/expoxy composites with good luminous performance and dispersibility.