Oxide Phosphor Composition for Broad Red-Near-Infrared Emission
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Solution Overview
Problem
There is a need for an oxide phosphor with a light emission peak wavelength in the red to near-infrared range and a wide full width at half maximum, suitable for various applications including medical imaging, food quality analysis, and plant growth promotion, as existing phosphors do not offer the desired spectral characteristics.
Innovation Solution
The development of an oxide phosphor with a composition represented by Formula (Li1−uM1u)2M2vM3wOx:Cry,M4z, where M1 is Na, K, or Cs, M2 is Mg, Ca, Sr, or Zn, M3 is Si, Ge, Ti, Zr, or Hf, and M4 is Ni, Eu, Fe, Mn, Nd, Ho, Er, or Yb, with specific molar ratios, and a method involving heat-treatment of a raw material mixture in an oxygen atmosphere to achieve the desired emission properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional phosphor (e.g., CaYAlO4:Mn4+) is used, then the phosphor can emit light in the red to near-infrared range, but the emission spectrum has a narrow full width at half maximum and limited spectral coverage
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor by incorporating multiple metal elements (M1: Na/K/Rb/Cs, M2: Mg/Ca/Sr/Ba/Zn, M3: Si/Ge/Ti/Zr/Hf, M4: Ni/Eu/Fe/Mn/Nd/Tm/Ho/Er/Yb) in specific molar ratios defined by Formula (1). This compositional parameter optimization enables the phosphor to achieve a full width at half maximum of 80 nm or greater while maintaining peak emission between 680-1050 nm, thereby expanding spectral coverage for diverse applications including medical imaging and plant growth promotion
Solution Approach 2:
The patent creates a composite phosphor material with a complex multi-element structure represented by Formula (Li1−uM1u)2M2vM3wOx:Cry,M4z. This composite material combines multiple metal oxides and activators to achieve superior emission characteristics that cannot be obtained with conventional single-phase phosphors, resulting in both narrow and wide spectral components that enhance adaptability for various applications
2Illumination intensity
If the phosphor composition is optimized for wider emission spectrum, then the full width at half maximum increases to 80 nm or greater, but the manufacturing precision and compositional control become more difficult
Solution Approach 1:
The patent establishes specific parameter ranges for compositional control: 0≤u≤1.0, 0.8≤v≤3.0, 1.8≤w≤6, 5.4≤x≤16, 0.005≤y≤1.0, and 0≤z≤0.5. These precisely defined parameters guide the manufacturing process to achieve the desired emission spectrum width while maintaining reproducible compositional control, resolving the contradiction between spectral performance and manufacturing precision
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 oxide phosphor achieves a light emission peak wavelength from 680 nm to 1050 nm with a full width at half maximum of 80 nm or greater, enhancing light emission intensity and spectral coverage for diverse applications, including medical imaging and plant growth promotion.
Implementation Method 1
a light-emitting device provided with the oxide phosphor and a light-emitting element that has a light emission peak wavelength in a range from 365 nm to 650 nm and irradiates the oxide phosphor
Implementation Method 2
obtaining an oxide phosphor by heat-treating the raw material mixture in an atmosphere containing oxygen at a temperature in a range from 800° C. to 1200° C.
Data Source
AI summary
Provided is an oxide phosphor having a light emission peak in a wavelength range from red light to near-infrared light. An oxide phosphor having a composition represented by Formula (1): (Li1−uM1u)2M2vM3wOx:Cry,M4z (1). wherein M1 is at least one element selected from the group consisting of Na, K, Rb and Cs; M2 is at least one element selected from the group consisting of Mg, Ca, Sr, Ba and Zn; M3 is at least one element selected from the group consisting of Si, Ge, Ti, Zr, Sn, and Hf; M4 is at least one element selected from the group consisting of Ni, Eu, Fe, Mn, Nd, Tm, Ho, Er, and Yb; and u, v, w, x, y, and z satisfy 0≤u≤1.0, 0.8≤v≤3.0, 1.8≤w≤6, 5.4≤x≤16, 0.005≤y≤1.0, and 0≤z≤0.5, respectively.