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A eu3+/dy3+ doped nayf4 single crystal for white light led and its preparation method

A single crystal and LED chip technology, applied in the field of white light LEDs, can solve the problems of easy distortion of white light, low color rendering index, high color temperature of white light, etc., and achieve good ultraviolet transmission performance of the matrix, good physical and chemical stability, and high optical transmission. Effect

Inactive Publication Date: 2016-06-08
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, most LED lighting devices are made of blue-emitting LED chips (mainly InGaN) and yellow phosphors (Ce 3+ :YAG) packaged together, the blue light emitted by the chip and the yellow light generated by the phosphor excited by the blue light are mixed into white light emission, but there are the following defects: (1) the color temperature of white light is high, and the color rendering index is low; (2) White light is easy to distort and drift, resulting in slightly blue or yellowish white light; (3) the coated phosphor has an adverse effect on white light due to the uneven particle size; (4) the organic epoxy resin used for encapsulation is in the light It is easy to age under irradiation; (5) the cost is higher, etc.
However, luminescent glass has major disadvantages such as physicochemical, thermal, anti-light radiation, and poor luminescent properties of rare earth ions, which have become the biggest bottleneck restricting its large-scale practical application.

Method used

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  • A eu3+/dy3+ doped nayf4 single crystal for white light led and its preparation method
  • A eu3+/dy3+ doped nayf4 single crystal for white light led and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Weigh 55.50mol% of NaF raw materials with a purity greater than 99.99%, YF 3 Raw material 43.40mol%, EuF 3 Raw material 0.30mol%, DyF 3 The raw material is 0.80 mol%, and after mixing, it is placed in a mill, and it is milled and mixed for 5.5 hours to obtain a mixture of uniform powder. Put the mixture in a boat-shaped platinum crucible loosely, and then install the boat-shaped platinum crucible in the platinum pipeline of the tubular resistance furnace, and then use high-purity N 2 Gas removes the air in the platinum pipe, and conducts leak detection on the platinum pipe; then gradually raises the temperature of the furnace body of the tubular resistance furnace to 810°C, passes HF gas, and reacts for 2 hours to remove possible H 2 O and oxyfluoride, during the reaction process, use NaOH solution to absorb HF gas in the tail gas. After the reaction, stop passing HF gas, close the tube resistance furnace, and finally use high-purity N 2 The gas removes the residual ...

Embodiment 2

[0021] It is basically the same as Example 1, the difference is only NaF raw material 55.50mol%, YF 3 Raw material 43.31mol%, EuF 3 Raw material 0.30mol%, DyF 3 The raw material is 0.89mol%, the reaction time in the platinum tube is 5 hours, the temperature gradient of the solid-liquid interface is 65°C / cm, the crystal growth rate is 0.2mm / h, and the furnace temperature drop temperature is 80°C / h. The rare earth Eu in the single crystal 3+ Concentration is 0.218mol%, Dy 3+ It is 0.828 mol%, m+n=0.01052, x:y=1:3.80. The X-ray diffraction pattern of the sample is similar to Example 1. For chromaticity coordinates see figure 2 , the color coordinates (x, y) are 0.317 and 0.326, and the color temperature is 6286K.

Embodiment 3

[0023] It is basically the same as Example 1, the difference is only NaF raw material 55.50mol%, YF 3 Raw material 43.45mol%, EuF 3 Raw material 0.30mol%, DyF 3 The raw material is 0.750mol%, the reaction time in the platinum tube is 4.5 hours, the temperature gradient of the solid-liquid interface is 70°C / cm, the crystal growth rate is 1.2mm / h, and the furnace temperature drop temperature is 65°C / h. The rare earth Eu in the single crystal 3+ Concentration is 0.218mol%, Dy 3+ It is 0.741 mol%, m+n=0.00959, x:y=1:3.40. The X-ray diffraction pattern of the sample is similar to Example 1. For chromaticity coordinates see figure 2 , the color coordinates (x, y) are 0.296 and 0.304, and the color temperature is 7929K.

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Abstract

The invention discloses a Eu<3+> / Dy<3+>-doped NaYF4 monocrystal for white light LEDs (light-emitting diodes) and a preparation method thereof. The NaYF4 crystal simultaneously contains the two rare earth ions Eu<3+> and Dy<3+> to generate a monocrystal of which the chemical formula is NaY(1-m-n)EumDynF4. The sodium yttrium fluoride monocrystal has the advantages of high solubility for rare earth and favorable thermal, mechanical and chemical stability. The rare earth ions doped in the monocrystal have high luminescence efficiency; and by adopting a water-free oxygen-free sealed crucible descending process and carrying out high-temperature fluoridation treatment on the raw material, the preparation method can be used for preparing the high-quality crystal which is almost free of hydroxide ions and oxides. The blue-green light and yellow light emitted by Dy<3+> can be mixed with the yellow light and red light emitted by Eu<3+> to emit white light. When the Dy<3+> / Eu<3+> atomic concentration ratio in the crystal reaches 3.4-3.8, under the excitation of 385nm light, the color coordinates emitted by white light are optimal, and the color coordinates x and y are approximate to the ideal value 3.0.

Description

technical field [0001] The present invention relates to white light LED, in particular to a kind of Eu for white light LED 3+ / Dy 3+ Doped with NaYF 4 Single crystal and its preparation method. Background technique [0002] LED (Light-emitting diode) is a new semiconductor solid light source that converts electrical energy into light energy. Due to its characteristics of energy saving, environmental protection, long life, low voltage safety, miniaturization and low loss, it has become the fourth generation of new lighting source, realizing real energy saving and green lighting. At present, most LED lighting devices are made of blue-emitting LED chips (mainly InGaN) and yellow phosphors (Ce 3+ :YAG) packaged together, the blue light emitted by the chip and the yellow light generated by the phosphor excited by the blue light are mixed into white light emission, but there are the following defects: (1) the color temperature of white light is high, and the color rendering i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B29/12C30B11/00
Inventor 夏海平符立董艳明李珊珊唐磊汪沛渊彭江涛张约品
Owner NINGBO UNIV