Triclinic MSi2N2O2 Phosphor for Thermal Stability
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Solution Overview
Problem
Conventional phosphors used with LEDs have weak emission intensity in the visible light region, particularly in the blue wavelength, and suffer from thermal quenching, where luminance decreases with temperature increases, and do not efficiently emit light in the desired wavelength when excited by ultraviolet rays or blue light.
Innovation Solution
A phosphor with a triclinic system crystal structure and chemical formula MSi2N2O2, where M=CaxSryEuz (x+y+z=1), is developed, which emits light with a peak wavelength between the green and yellow bands when excited by ultraviolet rays or blue light, maintaining high luminance and efficiency across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional phosphors are used, then they can be easily manufactured, but they exhibit weak emission intensity in the visible light region and suffer from thermal quenching
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating Sr and Eu elements in specific ratios (x+y+z=1) to achieve optimal emission intensity and thermal stability. The compositional parameters are optimized to balance brightness and temperature resistance
Solution Approach 2:
The patent uses a composite phosphor material combining multiple elements (Ca, Sr, Eu, Si, N, O) in a specific chemical formula MSi2N2O2. This composite structure integrates the advantages of different elements to achieve both high emission intensity and thermal stability
2Illumination intensity
If conventional phosphors are used, then they have simple crystal structures, but they do not efficiently emit light at desired wavelengths when excited by ultraviolet rays or blue light
Solution Approach 1:
The patent optimizes the crystal structure parameters (lattice constants a, b, c and angles α, β, γ) to achieve efficient light emission at desired wavelengths. The triclinic system with specific parameter relationships provides optimal optical properties for UV and blue light excitation
3Illumination intensity
If conventional phosphors are used, then they maintain simple chemical compositions, but their luminance is reduced with temperature increase
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating Sr and Eu elements in specific ratios (x+y+z=1) to achieve optimal emission intensity and thermal stability. The compositional parameters are optimized to balance brightness and temperature resistance
Solution Approach 2:
The patent uses a composite phosphor material combining multiple elements (Ca, Sr, Eu, Si, N, O) in a specific chemical formula MSi2N2O2. This composite structure integrates the advantages of different elements to achieve both high emission intensity and thermal 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 phosphor exhibits improved light emission intensity and luminance, with a peak wavelength close to the yellow band, and is less affected by temperature changes, enhancing quantum efficiency and light emitting properties compared to conventional phosphors.
Implementation Method 1
A phosphor is excited by light with a particular wavelength and emits light with a wavelength different from the particular wavelength
Data Source
AI summary
A phosphor and a light emitting device including the phosphor may be provided that emits light having a peak wavelength between a green wavelength band and a yellow wavelength band and has a triclinic system crystal structure of which the chemical formula is MSi2N2O2, M=CaxSryEuz(x+y+z=1), wherein, when three sides of a unit crystal lattice of the crystal structure are a, b and c and corner angles are α, β and γ, the crystal structure has relationships of a≠b≠c and α≠β≠γ, and wherein, in a, b and c, any one of them is more than twice as much as one of the other two, and the values of the other two are so similar that they do not exceed the double of each.