SCASN Phosphor Grain Boundary Control for Quantum Efficiency
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Solution Overview
Problem
The luminescent properties of SCASN phosphors are insufficient due to the presence of amorphous components at crystal grain boundary triple points, which inhibit light emission and reduce internal quantum efficiency.
Innovation Solution
By controlling the ratio of crystal grain boundary triple points to phosphor particles to 1.0 or less, and optimizing the chemical composition within specific ranges, the phosphor particles are three-dimensionally coupled, enhancing luminescent properties and internal quantum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If SCASN phosphor is used with high Sr content to improve red emission intensity, then the emission intensity is enhanced, but amorphous components form at crystal grain boundary triple points which inhibit light emission and reduce internal quantum efficiency
Solution Approach 1:
The invention changes the chemical composition parameters by strictly controlling the Sr content to 0.95 or less and optimizing the ratios of Ca, Al, Si, and N elements. This parameter optimization prevents the formation of amorphous components at crystal grain boundaries while maintaining high emission intensity, thereby resolving the contradiction between emission intensity and internal quantum efficiency
Solution Approach 2:
The invention addresses the local quality issue at crystal grain boundary triple points by controlling the composition to prevent amorphous phase formation in these critical regions. By ensuring uniform crystalline structure throughout the phosphor particles, the light emission is no longer inhibited at grain boundaries, thus improving internal quantum efficiency while preserving overall emission intensity
2Stability of the object's composition
If sulfur or phosphorous is controlled to specific composition regions, then the composition is stabilized, but luminescent properties remain insufficient due to crystal grain boundary triple points
Solution Approach 1:
The invention optimizes the composition parameters including controlled amounts of sulfur and phosphorous along with Sr (0.95 or less), Cu, Al, Si, and N. This comprehensive parameter optimization ensures the composition falls within a specific stable region that promotes complete crystallization, eliminating amorphous components at grain boundaries while maintaining composition stability and achieving sufficient luminescent properties
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
This approach results in a phosphor with improved luminescent properties and high internal quantum efficiency, leading to high-quality light-emitting devices, image display devices, and illumination devices.
Implementation Method 1
a white light-emitting LED in which a phosphor is disposed on an LED chip that emits light of a wavelength of blue or near ultraviolet
Data Source
AI summary
The present invention relates to a phosphor represented by the Formula [1]: MaSrbCacAldSieNf, wherein the phosphor includes phosphor particles in which single crystallites are three-dimensionally coupled to each other, the phosphor particles include a crystal grain boundary triple point, and [a total number of the crystal grain boundary triple points (A)]/[the number of the phosphor particles (B)] is 1.0 or less.