High-efficiency single-band up-conversion red light nanocrystalline material

Abstract

The invention belongs to the field of inorganic luminescent materials, and relates to a high-efficiency single-band up-conversion red light nanocrystalline material NaErF4:Gd / Tm@NaYF4:Gd@IR-806. The preparation method of the high-efficiency single-band up-conversion red light nanocrystalline material sequentially comprises the following steps: adding gadolinium acetate, erbium acetate, thulium acetate, oleic acid and octadecene into a three-necked bottle to obtain an anhydrous transparent solution A; after the solution A is naturally cooled to 50 DEG C, adding a methanol solution of ammonium fluoride and sodium hydroxide into the solution A in a dropwise manner; after the methanol solution is completely volatilized, raising the temperature, keeping the temperature, and naturally cooling toroom temperature; washing the solution with a mixed solution of ethanol and cyclohexane to obtain core nanocrystals, and then preparing core-shell nanocrystals through a layer-by-layer epitaxial growth method; removing the oleic acid ligand on the surface of the core-shell nanocrystal through acid treatment to convert the core-shell nanocrystal into a hydrophilic nanocrystal; and preparing an IR-806 organic dye by adopting a standard Schlenk technology, and compounding to obtain the core-shell nanocrystal coated with the organic dye. The method has the advantages that the preparation cost islow, the yield is high, and the product has the characteristic of high-efficiency single-band red light emission under the 800 nm excitation condition.

Description

technical field [0001] The invention belongs to the field of inorganic light-emitting materials, in particular to single-band up-conversion red light nanocrystal materials. Background technique [0002] Up-conversion luminescence refers to the transformation of low-energy photons in the long-wave region into high-energy photons in the short-wave region by absorbing two or more photons, which is a nonlinear optical process. The excitation source of upconversion luminescent nanomaterials is usually near-infrared laser. In the process of cell imaging, it has the characteristics of deep penetration depth, no spontaneous background fluorescence, and excellent signal-to-noise ratio, which can improve the sensitivity and spatial resolution of biological imaging. At present, the main research system is to produce rare earth ion-doped fluoride nanocrystals with multi-band emission under the excitation of 980nm laser. They should have many shortcomings in the field of biological imagi...

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Problems solved by technology

At present, the main research system is to produce rare earth ion-doped fluoride nanocrystals with multi-band emission under the excitation of 980nm laser. They should have many shortcomings in the field of biological imaging. For example, first, although the excitation light source is located in the near-infrared region, It can achieve a large penetration depth, and the commonly used up-conversion luminescent rare earth ions (Er 3+ , Ho 3+ , Tm 3+ ) is dominated by green light (~550nm) or blue light (~475nm), and the red light and near-infrared light in the 600-1000nm band are relatively weak, so it is difficult for the emitted light to penetrate deeper biological tissues, and the laser Changes in power and depth of biological tissue will have different effects on different emission bands, which will lead to chromatic aberration and ultimately affect the biological imaging effect; second, water molecules in biological tissue have strong absorption near 980nm, resulting in 980nm The penetration depth of the laser is greatly reduced, and the water molecules in the biological tissue absorb a large amount of photon energy with a wavelength of 980nm to generate local heat energy, resulting in damage to the biological tissue; third, because the photon absorption process of the trivalent rare earth ion is a forbidden transition, The transition probability is very low, and the corresponding absorption band is very narrow, resulting in very low upconversion luminous efficiency, usually less than 1%

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