Near-infrared light emitting lanthanum oxysulfide fluorescent powder and method for preparing same

Abstract

The invention discloses near-infrared light emitting lanthanum oxysulfide fluorescent powder and a method for preparing the same. A chemical formula of the near-infrared light emitting lanthanum oxysulfide fluorescent powder is (La<x>Yb<y>Tm<z>)<2>O<2>S. The sum of the x, the y and the z is equal to 1, the x is larger than or equal to 0.7 and is smaller than or equal to 0.98, the y is larger thanor equal to 0.01 and is smaller than or equal to 0.2, and the z is larger than or equal to 0.01 and is smaller than or equal to 0.1. The method includes adding distilled water into lanthanum oxide powder, ytterbium oxide powder and thulium oxide powder; stirring and heating the lanthanum oxide powder, the ytterbium oxide powder and the thulium oxide powder to obtain liquid, and dropwise dropping concentrated nitric acid until the liquid is clear; preparing lanthanum nitrate solution, ytterbium nitrate solution and thulium nitrate solution with corresponding concentration; mixing the lanthanumnitrate solution, the ytterbium nitrate solution and the thulium nitrate solution with one another according to proportions to obtain mixed solution; adding ammonium sulfate particles into the mixed solution and stirring the ammonium sulfate particles and the mixed solution until the mixed solution is clear; adding ammonia water into the mixed solution, regulating the pH (potential of hydrogen), and stirring the mixed solution to obtain uniform suspension; carrying out reaction at the temperatures for the time under the control; separating and drying products and calcining the products in hydrogen to obtain the near-infrared light emitting lanthanum oxysulfide fluorescent powder. The near-infrared light emitting lanthanum oxysulfide fluorescent powder and the method have the advantages that nearly pure near-infrared light (with the lengths of 802nm) can be emitted by the near-infrared light emitting lanthanum oxysulfide fluorescent powder prepared by the aid of the method, stray lightpositioned in visible light regions nearly can be completely quenched, and accordingly the color purity and the mark signal strength can be advantageously improved.

Description

Technical field: [0001] The invention belongs to the technical field of material science, and in particular relates to a lanthanum oxysulfide fluorescent powder emitting near-infrared light and a preparation method thereof. Background technique: [0002] Up-conversion luminescent materials have been widely used in many fields because of their unique ability to convert low-energy long-wavelength light into high-energy short-wavelength light, such as infrared detection, long-lasting luminescent warning signs, fire exit signs or indoor wall coatings. Up-conversion materials can also be used as biomarkers, biomonitoring, drug therapy, computed tomography (Computed Tomography, CT), magnetic resonance imaging (Magnetic Resonance Imaging, MRI), marking, etc. Materials that can emit near-infrared light with a wavelength of 750-1000nm are suitable for biomarkers, because hemoglobin and oxyhemoglobin in mammals mainly absorb visible light, and water mainly absorbs infrared rays, so th...

AI Technical Summary

Problems solved by technology

Although fluorescent materials that emit near-infrared light are currently available, pure near-infrared light is often difficult to obtain. When near-infrared light is obtained, there are often other colors (such as blue light and red light) in the visible light region, resulting in insufficient color purity. , which affects the marker signal

In addition, NaYF, a commonly used up-conversion material with higher efficiency, 4 :Tm / Yb has certain toxicity due to fluorine content, which is harmful to human body and has poor stability

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