Orange red fluorescent powder for LED and preparation method thereof

Abstract

The invention discloses orange red fluorescent powder for an LED (Light Emitting Diode), which is germanate fluorescent powder activated by trivalent samarium. The chemical expression of the fluorescent powder is (Ma-xSmx) GebOc, wherein the M is at least one of Li, Na, K, Mg, Ca, Sr, Ba and Zn; the a is more than 0 and less than or equal to 6; the b is more than or equal to 1 and less than or equal to 11; the c is more than or equal to 3 and less than or equal to 25; and the x is more than 0 and less than 0.3. The preparation method comprises the following steps of: uniformly grinding and mixing simple substances and compounds of M, Ge and Sm or the corresponding salts, then roasting at high temperature, and preparing the fluorescent powder after crushing, cleaning to eliminate impurities and baking. The fluorescent powder has the characteristics of wide excitation wavelength range, high efficiency, stability and the like, and has the advantages of simple preparation method, no pollution and low cost. The fluorescent powder can be used for a purple light or ultraviolet light LED chip to manufacture a white light LED.

Description

technical field [0001] The invention relates to a germanate orange-red fluorescent powder and a preparation method thereof, in particular to an orange-red fluorescent powder suitable for LEDs and a preparation method thereof, and belongs to the technical field of rare earth luminescent materials. Background technique [0002] In the 1990s, with the technological breakthrough of high-brightness GaN blue LEDs, in 1996, blue LEDs and YAG phosphors ((Y, Gd) appeared. 3 Al 5 o 12 : Ce 3+ ) combined white light LED, which is considered to be another leap in the history of human lighting after incandescent lamps and fluorescent lamps, and is one of the most promising high-tech fields in the 21st century. There are three ways to produce white light with phosphor: blue LED chip with yellow phosphor; blue LED chip with red and green phosphor; UV-LED chip with red, green and blue phosphors. At present, the commercial products are mainly single-chip high-brightness white LEDs compos...

AI Technical Summary

Problems solved by technology

At present, the commercial products are mainly single-chip high-brightness white LEDs composed of blue LED chips and yellow light of YAG phosphor powder. As a result, the color rendering is not good, and red phosphor can be added to obtain a high color rendering index

However, in the prior art, some phosphors used for white LEDs lack red light components, or the red phosphors have low luminous efficiency or are unstable, such as several sulfide red phosphors reported in US Patent 6252254

The white LEDs packaged in the prior art have low color rendering index or low efficiency or unstable performance

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