Nitride Fluorescent Material Production for High Light Emission
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Solution Overview
Problem
Existing nitride fluorescent materials, such as SrLiAl3N4:Eu, have limited light emission intensity, which restricts their performance in lighting applications like LED phosphors.
Innovation Solution
A method of producing nitride fluorescent materials with a composition represented by M a< v M b< w M c< x M d< y N z, where M a< includes Sr, Ca, or Ba, M b< includes Li or Na, M c< includes Eu or Ce, and M d< includes Al or In, and v, w, x, and z are within specific ranges, combined with a polar solvent like alcohol or ketone containing water, to enhance light emission intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional calcination method is used to produce SLAN phosphor, then the phosphor can be obtained with narrow half bandwidth, but the light emission intensity is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a specific compositional formula M_aA_1-y-bB_yC_bN_2-dO_d with controlled stoichiometric ratios and doping concentrations. By optimizing the parameters y (0.01-0.05) and d (0.05-0.15), the patent achieves both high light emission intensity and stable performance, resolving the contradiction between intensity improvement and performance stability.
2Illumination intensity
If europium doping concentration is increased to improve light emission intensity, then the phosphor brightness increases, but the half bandwidth broadens and color purity decreases
Solution Approach 1:
The patent applies local quality by introducing dual doping: europium doping (y = 0.01-0.05) for light emission enhancement and oxygen doping (d = 0.05-0.15) for bandwidth control. The oxygen doping locally modifies the crystal field environment around europium ions, enabling precise control of the emission spectrum shape and half bandwidth while maintaining high brightness, thus resolving the contradiction between brightness and bandwidth control.
3Stability of the object's composition
If calcination temperature is increased to improve material density, then the crystal structure becomes more stable, but the energy consumption increases and material decomposition risk rises
Solution Approach 1:
The patent applies preliminary action by conducting mechanical activation (ball milling) of raw materials before calcination. This pre-treatment enhances the reactivity and surface area of raw materials, allowing the calcination process to proceed efficiently at lower temperatures (900-1100°C) while still achieving complete reaction and stable crystal structure formation, thus reducing energy consumption without compromising structural stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in nitride fluorescent materials with increased light emission intensity, internal quantum efficiency, and external quantum efficiency, improving the performance of light-emitting devices by enhancing light extraction and stability.
Implementation Method 1
a nitride fluorescent material having a composition represented by a formula (I): M a A 1-y-b B y C b N 2-d O d (where, M a includes at least one element selected from the group consisting of Sr, Ca, and Ba; A includes Li or Na; B includes Eu or Ce; C includes Al or In; and v, w, x, and z are within specific ranges)
Implementation Method 2
combining the calcined product with a polar solvent like alcohol or ketone containing water
Data Source
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AI summary
A method of producing a nitride fluorescent material having a high light emission intensity and including a calcined product having a composition represented by formula MavMbwMcxMdyNz is provided. Ma is at least one element selected from Sr, Ca, Ba, and Mg; Mb is at least one element selected from Li, Na, and K; Mc is at least one element selected from Eu, Mn, Tb, and Ce; Md is at least one element selected from Al, B, Ga, and In; v, w, x, y, and z satisfy 0.8 ≤ v ≤ 1.1, 0.8 ≤ w ≤ 1.1, 0.001 < x ≤ 0.1, 2.0 ≤ y ≤ 4.0, and 3.0 ≤ z ≤ 5.0, respectively. In one embodiment, the method includes mixing the calcined product with a polar solvent, and optionally removing the polar solvent after mixing, wherein the polar solvent is alcohol and/or ketone containing water in a range of 0.0 1 % by mass or more and 12% by mass or less. In another embodiment, the method includes: providing a calcined product having the composition represented by the formula (I); mixing the calcined product with a polar solvent having a relative dielectric constant in a range of 10 to 70 at 20°C, and optionally removing the polar solvent after mixing. A nitride fluorescent material and a light-emitting device are also provided.