A kind of yb for white light led 2+ Excited nitrogen oxide green fluorescent material and preparation method thereof

Abstract

The invention relates to the technical field of rare-earth light emitting materials and in particular discloses a Yb<2+> excited nitric oxide green fluorescent material for a white light LED (light emitting diode) and a preparation method of the fluorescent material. The fluorescent material has a chemical expression formula of Ca2-xSi3O2N4: xYb<2+>, and in the formula, x is greater than or equalto 0.01 and less than or equal to 0.06. The preparation method comprises the following steps: accurately weighing CaCO3, NH4H2PO4 and Yb2O3 according to a chemical mole ratio; obtaining a precursor Ca3-x(PO4)2: xYb<3+> through mixing, grinding, and high-temperature sintering; mixing and grinding the precursor with Si3N4, carrying out high-temperature sintering, and introducing an N2 / H2 mixed gas,thereby obtaining the fluorescent material. The fluorescent material provided by the invention has excellent light emission properties, has effective broadband absorption from an ultraviolet region toa blue light region, is matched with a chip of a commercial LED, and has an emission wave peak at 545nm. The fluorescent material is short in preparation cycle, simple in process procedure, low in equipment requirement, green and environmentally-friendly in synthesis process and beneficial to large-scale production.

Description

technical field [0001] The invention belongs to the technical field of rare earth luminescent materials, in particular to Yb for white light LEDs 2+ Excited nitrogen oxide green fluorescent material and preparation method thereof. Background technique [0002] White light LED is a new generation of green lighting source, and its white light is mainly emitted by phosphor conversion method. Traditional oxide, sulfide, and halide system phosphors have poor stability and unstable chemical properties, while borate, silicate, and aluminate system phosphors have stable chemical properties, but have a single structure and single spectral properties, making it difficult to Match with specific LED chips. Therefore, nitrogen oxide fluorescent materials with stable physical and chemical properties, rich spectral properties and environmental friendliness have received extensive attention since their inception. [0003] At present, the preparation of nitrogen oxide fluorescent material...

AI Technical Summary

Problems solved by technology

[0003] At present, the preparation of nitrogen oxide fluorescent materials usually requires the use of alkaline earth metal nitrides or high-purity metal powders as matrix materials, and many of them also use rare earth nitrides as doping materials. 2 It is extremely sensitive to moisture and moisture, so it must be operated in a vacuum glove box or a pure nitrogen glove box, otherwise it is easy to be oxidized and has the possibility of explosion, so it is not suitable for mass production in the market

However, cheap alkaline earth metal carbonates are not suitable for the stable production of nitrogen oxides because of their oxygen content, which can cause unpredictable damage to the nitriding process.

[0004] As an essential raw material for the preparation of silicon-based oxynitride, Si 3 N 4 The powder has a strong covalent bond, resulting in low diffusion coefficient and poor reactivity. Therefore, a high synthesis temperature is required in the preparation process of silicon-based oxynitride, and high-pressure nitrogen gas needs to be introduced to inhibit its decomposition, which leads to A substantial increase in production costs seriously affected the process of its commercialization

In the past, the activator used to obtain green light was mainly Eu 2+ and Tb 3+ , both of which have small absorption cross section and high price

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