Near-ultraviolet-excited white-light LED (light-emitting diode) fluorescent powder and preparation method thereof

Abstract

The invention discloses near-ultraviolet-excited white-light LED (light-emitting diode) fluorescent powder and a preparation method thereof, and relates to the field of rear-earth-doped light-emitting materials and solid illumination. The fluorescent powder material takes molybdate/tungstate as a substrate, and has a chemical formula of AR2(WO4)4-x(MoO4)x:Eu<2+>, Mn<2+>, wherein A is one or a combination of more of Mg, Ca, Sr, Ba, Cu and Zn; R is one or a combination of more of Al, Sc, La, Gd, Y, Bi and the like; x ranges from 0 to 4. The fluorescent powder disclosed by the invention is stable in physical and chemical properties while being excited by near ultraviolet, and excellent in luminescence property at a high temperature, and the substrate of the material can absorb near-ultraviolet photons which are transmitted to Eu<2+> and Mn<2+> ions through energy, so that fluorescent emission excitement of the Eu<2+> and Mn<2+> ions within a range of 420 nm to 650 nm can be realized. The fluorescent powder material has the advantages of high absorption efficiency, stable performance, high light-emitting efficiency, adjustable color and the like in a near-ultraviolet region, and the preparation process is simple.

Description

technical field [0001] The invention relates to the technical field of LED lighting, in particular to a white LED fluorescent powder and a preparation method thereof. Background technique [0002] White LED is a new type of green solid-state lighting source with unlimited application potential. Compared with other energy-saving lamps and incandescent lamps, white LED has the advantages of low operating voltage, low power consumption, high reliability, long life, no pollution and high efficiency. The series of good characteristics are also the research focus of solid-state lighting sources. Phosphor powder is one of the main components in white LED solid-state lighting sources. The performance of phosphor powder determines key technical indicators such as LED luminous efficiency, color rendering index, color temperature and service life. Therefore, phosphors play an important role in white LED solid-state lighting, and are the research focus of the majority of researchers to...

AI Technical Summary

Problems solved by technology

[0004] The first is to realize white light emission through the combination of red, green and blue primary color LED chips. However, to realize LED white light output through this method needs to consider the driving characteristics of three different LED chips, which leads to complex circuit design of the light source.

The second is the integrated single-chip method, also known as the multi-quantum well method, which uses multiple active layers on a single chip to make the LED chip emit white light directly. The main defect of this method is the single-chip growth of multiple active layers. Complex technology and difficult control

The third method is the phosphor conversion method. There are two ways to achieve this method. One is to coat the blue LED chip with yellow phosphor to realize the white LED, wherein the blue light emitted by the InGaN chip is used to excite YAG: The method of Ce3+ yellow light phosphor to realize white light LED has developed rapidly and has been commercialized, but the main disadvantages of this scheme are also obvious, mainly because white light is formed by combining blue light and yellow light, and its composition lacks red light, making The white light emitted has a low color rendering index; another solution is to use ultraviolet or near-ultraviolet LEDs to excite red, green and blue three primary color phosphors to achieve white light emission. This solution also has many defects, mainly reflected in: the aging of the three phosphors There is a significant difference in the degree of white light, resulting in a shift in the color coordinates of white light; at the same time, the phosphors of the three primary colors will absorb each other, especially the absorption of red light by blue-green phosphors, which will lead to a significant decrease in luminous efficiency; finally, phosphors in ultraviolet light Poor stability under excitation, resulting in low lumen efficiency of white LEDs

In these borates and phosphates, although good white LED output with color temperature and display index can be obtained, the main defect of these materials is: the absorption of the material in the near ultraviolet is not high, resulting in poor luminous efficiency; at the same time, manganese Ions can have a strong emission through the sensitization of europium, but the overlap between the excitation spectrum and emission spectrum of these two ions is not high, which will also limit the luminous efficiency of the material; finally, due to the low absorption of the material in the near ultraviolet, it will This leads to a large amount of residual ultraviolet light under near-ultraviolet excitation, which is a great obstacle to the application of materials in the field of lighting