Cr3+-Doped Pyroxene Phosphors for Broadband NIR Emission
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Solution Overview
Problem
Existing luminescent materials often lack broad band emission, thermal stability, and chemical stability, particularly in the near-infrared (NIR) spectral range, with many exhibiting low quantum efficiency and being susceptible to quenching at relatively low temperatures and chemical instability.
Innovation Solution
Development of a luminescent material composition E1-wSc1-x-y-u-wMyZuA2wSi2-z-uGezAluO:Crx, where Cr3+ substitutes for octahedrally coordinated Sc and/or M atoms, emitting in the 700-1100 nm range, with adjustable emission band shape and position by varying Sc and M atom ratios, and incorporating Mg or Ni to enhance stability and quantum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional phosphor materials are used to achieve NIR emission, then the emission can be generated, but the quantum efficiency is low and thermal stability is poor
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific ratios of Sc, Lu, Al, Ga, In, and Cr elements in the pyroxene structure. By optimizing the Cr3+ concentration (0.01-0.10 mol ratio) and adjusting the Sc/Lu/Al/Ga/In ratios, the patent achieves both high quantum efficiency (40-80%) and improved thermal stability with quenching temperature above 500°C.
Solution Approach 2:
The patent creates a composite phosphor material with multi-element composition (Sc, Lu, Al, Ga, In, Cr) in a pyroxene host structure. This composite approach combines the advantages of different elements: Sc and Lu provide structural stability, Al/Ga/In tune the emission wavelength, and Cr3+ provides the NIR emission center, achieving synergistic improvement in both quantum efficiency and thermal stability.
2Illumination intensity
If phosphor concentration in the optical path is increased to improve emission intensity, then more light can be generated, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent optimizes the phosphor concentration parameter to a specific range (0.01-0.10 mol ratio of Cr3+) and adjusts the particle size distribution (0.1-10 μm) to achieve high emission intensity while maintaining simple device structure. The optimized concentration ensures sufficient light absorption without requiring complex multi-layer phosphor structures.
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 luminescent material achieves high quantum efficiency exceeding 40%, broad emission, and improved thermal and chemical stability, enabling efficient broadband NIR emission when combined with blue or UV radiation, suitable for phosphor-converted LEDs.
Implementation Method 1
Cr3+ substitutes for the octahedrally coordinated Sc and/or M atoms, such as Lu and/or Al, and emits in the 700-1100 nm spectral range
Data Source
AI summary
The invention provides luminescent material comprising E1-wSc1-x-y-u-wMyZuA2wSi2-z-uGezAluO6:Crx, wherein:E comprises one or more of Li, Na, and K;M comprises one or more of Al, Ga, In, Tm, Yb, and Lu;Z comprises one or more of Ti, Zr, and Hf;A comprises one or more of Mg, Zn, and Ni;0<x≤0.25;0≤y≤0.75;0≤z≤2;0≤u≤1;0≤w≤1;x+y+u+w≤1; andz+u≤2.