Fabrication And Properties Of NaYF₄-based Upconversion Nanomaterials

Upconversion nanomaterials are a new type of fluorescent materials compared with thetraditional organic dyes and quantum dots, which have the merits of low toxicity, highchemical stability, excellent light stability, narrow band emission and long luminescence life.In addition, the near infrared laser as the excitation light source has many advantages, forinstance, lower background fluorescence, almost no damage to the biological tissue, deeplight penetration depth and so on.Yb³⁺, Er³⁺doped sodium yttrium fluoride （NaYF₄） was selected as an up-conversionfluorescent material, on which polyacrylic acid （PAA） was coated. Taking advantages of theup-conversion fluorescence capacity of Yb³⁺, Er³⁺doped NaYF₄and the drug loadingcapacity of PAA, the obtained nanomaterials possess both up-conversion fluorescence andhigh drug loading capacity. In addition, the properties were studied. In this thesis, wedesigned and fabricated up-conversion fluorescent nanomaterial in the water phase with waterusing ethanol as solvent, dodecanedioic acid as surface active agent, rare earth elementserbium as luminescent centers, rare earth element ytterbium as sensitization center and NaYF₄as matrix material. Furthermore, the effect of the reaction time and the amount of surfactanton the synthesis of nanoparticles were investigated. Doping is a common method in materialscience, which makes the elements, atoms, or ions enter into the host lattice, and then thenanomaterials with good performance were obtained. Based on the simple metal ion dopingmethod, when cadmium and cobalt were added to the reaction system, the morphology ofnanoparticles was changed. Most importantly, cobalt and cadmium doped up-conversionfluorescent nanomaterials are rarely reported.