Blue-light and near ultraviolet excitation type hydrothermal one-dimensional red nanometer fluorescent powder preparation method

Abstract

The invention discloses a hydrothermal nanometer fluorescent powder preparation method, belongs to the technical field of fluorescent powder preparation, and aims to provide a one-dimensional red nanometer fluorescent powder preparation method. The hydrothermal preparation method includes the steps of determining a molar ratio of components according to a general chemical formula Ca(1-z)RwOu:zEu3+ or MyCa(1-x-y)RwOu:xEu3+, and preparing various raw materials proportionally; dripping the raw materials into a certain concentration of ammonium bicarbonate solution at a certain speed, stirring with aging for 24 hours, and performing water washing for filtering for 4 times continuously to obtain a precursor; placing the obtained precursor into a mixed solvent of absolute ethyl alcohol and water to obtain a mixture, pouring the mixture into a stainless steel autoclave with a silver liner, and heating to 350 DEG C at the speed of 1.5 DEG C/min; keeping the temperature at 350 DEG C for 4 hours, powering off, cooling to a room temperature naturally, taking an obtained product out, and subjecting the product to water washing, suction filtering and drying to obtain the nanometer fluorescent powder. The blue-light and near ultraviolet excitation type hydrothermal one-dimensional red nanometer fluorescent powder preparation method has the advantages of low cost and safety in operation, and the prepared one-dimensional red nanometer fluorescent powder is regular in shape and small in granularity.

Description

technical field [0001] The invention belongs to the technical field of fluorescent powder preparation, and relates to a hydrothermal preparation method of blue light and near ultraviolet excitation type one-dimensional red nano fluorescent powder. Background technique [0002] Solid-state lighting is a technology that uses semiconductor light-emitting diodes (LEDs) to manufacture lighting sources. It has significant advantages such as green environmental protection, good weather resistance, high theoretical light efficiency, energy saving, long life, rich colors, fast response, easy miniaturization and maintenance-free. , so it is known as a new generation of light sources after incandescent lamps, fluorescent lamps and energy-saving lamps. It is expected to replace traditional lighting sources and has very broad application prospects. Based on the current development of LED technology and production costs, the way to obtain white LEDs is mainly to use near-ultraviolet or bl...

AI Technical Summary

Problems solved by technology

Compared with blue and green phosphors, Y2O2S:Eu3+ has the following outstanding disadvantages: expensive; can not effectively absorb excitation light around 400nm; emits sulfide gas under ultraviolet light irradiation, pollutes the environment, resulting in unstable chemical properties and shortened service life ; while the phosphors of the aluminate system have disadvantages such as poor moisture resistance, single luminous color, etc., and the cost is high, and the synthesis conditions are relatively harsh; the phosphors of the molybdate system have weak luminous intensity, which limits its application to a large extent. scope

A large number of defects in nanomaterials can form energy transfer with active center ions, so that energy transfer between nanomatrix and active center ions can make it contribute to the luminescence of phosphors. Therefore, by integrating nanomatrixes, especially one-dimensional nanomatrixes and The excellent optical properties of both rare earth ions can further improve the luminescent properties of phosphors, which cannot be achieved in micron-scale matrix phosphors prepared by traditional methods (such as high-temperature solid-phase method)

At present, the research on nano-matrix phosphors is mainly focused on nanoparticles. The research has observed that the luminous efficiency is improved, the fluorescence is enhanced, and the quenching concentration of rare earth ions in nanocrystals is higher than that of bulk materials, but it is also found that there is no radiation. The transition is significantly improved, resulting in a decrease in quantum efficiency

The main reason is that nanoparticles are a three-dimensional restricted system, and it is difficult to effectively control a large number of surface defects on the surface. These surface defects, while becoming radiation centers, also serve as channels for non-radiative transitions, improving nano Nonradiative transition rates of particles, reducing electronic transition rates and quantum efficiencies of rare earth ions in zero-dimensional nanoparticles

[0005] Traditional red phosphors generally use high-temperature solid-phase method, which has low doping concentration, poor doping uniformity and particle size uniformity, high sintering temperature, high energy consumption, many processes, high cost, and difficulty in forming nanoscale matrix, etc. defect

The preparation of micro / nano-particle three-color phosphors generally adopts the sol-gel method, although the sol-gel method has: (a) low operating temperature; (b) easy to accurately control the doping amount; (c) can avoid the experimental The introduction of impurities maintains the purity of the sample; (d) the precursor solution is mixed at low temperature and can achieve a high degree of uniformity at the molecular level, but there are also the following disadvantages: (a) the entire sol-gel process requires It takes a long time and often takes several days or weeks; (b) the final product still needs a calcination process to obtain, which increases the production cycle and cost; (c) there are a large number of micropores in the gel, and the calcined Many gases and harmful gases such as organic matter will escape, and shrinkage and agglomeration will occur. After calcination, the particles will grow up and the sintering performance will be poor.

The hydrothermal method is a new method developed in recent years for the preparation of one-dimensional nanomaterials. It has: (a) easy operation; (b) sufficient conversion of raw materials; (c) can form a special high temperature and high pressure environment, making it difficult to The characteristics of soluble or insoluble substances are dissolved and recrystallized. By controlling the molar ratio of raw materials, reaction temperature, reaction time and filling degree, it is very convenient to synthesize large-scale one-dimensional nanomaterials with uniform diameter distribution. However, hydrothermal There are relatively few studies on the preparation of phosphors by the hydrothermal method, mainly because the temperature of the hydrothermal method is relatively high, the requirements for equipment are relatively high, the technology is difficult, and the safety performance is poor.