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Upconversion luminescence material is an important class of luminescent materials, and by a multi-photon mechanism infrared optical conversion into visible light, which is characterized by the absorption of the photon energy is lower than the photon energy of the emitted light, also known as anti-Stokes materials, such The light emitting called anti-Stokes luminescence. Upconversion luminescence material in small solid-state lasers, infrared quantum counting detector, have important applications in the field of temperature sensors, solar cells, three-dimensional presentation, anti-counterfeiting technology, and Immunology. In recent years, the nanoscale rare earth conversion luminescent materials (upconversion nanoparticles, UCNPs) as a new type of fluorescent markers in biological macromolecules testing, medical imaging, and other aspects of application are increasingly subject to the attention of researchers, increasing number of reports. With traditional fluorescent markers, as compared to the organic dye, quantum dots, etc., the upconversion luminescence nanomaterials having excitation light energy is low, the narrow emission spectrum Stokes displacement, good chemical stability, high luminous intensity and stability, the emission wavelength can be be adjusted by controlling the composition and low toxicity. Further, the rare earth upconversion excitation light source of the light emitting nano-materials is usually near infrared continuous laser (typically is 980 nm), the biological sample can be avoided in this excitation conditions interference of fluorescence and scattered light phenomenon, no damage to the biological tissue, light deeper penetration depth, thereby reducing the detection background and improve the signal to noise ratio. Therefore, the upconversion luminescence nanomaterials as fluorescent markers in biological macromolecules and medical field of clinical testing have a very good prospect. Top upper conversion nano matrix material such as oxide, sulfide, fluoride, and phosphate, in which the hexagonal phase NaYF 4 for the matrix of the upconversion luminescence maximum efficiency. According to reports, the current can be used for biological detection on conversion fluorescent markers Yb / Er and Yb / Tm codoped NaYF 4 nanoparticles. Have reported recently many the organic phase NaYF 4 : Yb, Er / Tm Synthesis, excellent in its morphology and the light emitting performance, these nano-particles of poor water-soluble, however, limit their use in biological systems Application The NaYF synthesis of high-performance, hydrophilic 4 : Yb, Er / Tm upconversion emitting nanomaterials expand its premise in the biological and medical applications, is of great significance. As we all know, gold nanoparticles absorb in the UV-visible region. 15 nm gold nanoparticles has an absorption maximum at 520 nm, and the absorption coefficient, and the NaYF 4 : Yb, Er fluorescence peak position matching, fluorescence resonance energy transfer between the two can be constructed (FRET) system. FRET because of its sensitivity to distance, widely used in the study of biological macromolecular structure, the nature of the reaction mechanism as well as quantitative analysis. In this paper, nanomaterials, nano overview of the development of fluorescent probes, rare earth conversion luminescent nanomaterials preparation progress, optical properties and potential applications. On this basis, the following aspects of the work were carried out: 1 Solvothermal oleic acid in stable the NaYF 4 : Yb, Er UCNPs and successful use of β-ring The organic phase synthesis dextrin Zhi.A the NaYF 4 : Yb, Er UCNPs transferred to the aqueous phase. 2, the synthesis of ethylenediamine-β-cyclodextrin (CDEN), and applied to the phase transfer process, the surface with an amino group of the water-soluble NaYF 4 : Yb, Er UCNPs . 3, the FRET-based principle, the gold particles and the β-cyclodextrin coated NaYF 4 : Yb, Er UCNPs use of boric acid ester bond linking the D-fructose with phenylboronic acid has a strong complexation, addition of D-fructose, the gold particles and the NaYF 4 : Yb, Er UCNPs distance between the increases, thereby preventing the fluorescence resonance energy transfer, the NaYF 4 : Yb, Er UCNPs fluorescence recovery, to achieve the purpose of determination of fructose. 4 Hydrothermal Synthesis of the NaYF 4 : Yb of Er upconversion nanorods, and explore the nanorod surface first and then coated porous silica ligand exchange conditions.
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