Garnet Phosphor Reducing Temperature Quenching
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Solution Overview
Problem
The Lu2CaMg2(SiO4):Ce3+ phosphor experiences significant temperature quenching when excited by a laser beam, leading to inefficient light emission, particularly for wavelengths beyond 585 nm, which is a non-negligible issue in light emitting devices.
Innovation Solution
A phosphor with a garnet structure, where a part of calcium in Lu2CaMg2(SiO4)3 is replaced by magnesium, maintaining the garnet structure and reducing temperature quenching without shifting the light emission peak wavelength significantly, represented by the formula Lu2(Ca1-xMgx)Mg2(SiO4)3, where x ranges from 0.03 to 0.3, ensuring effective emission properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If Lu2CaMg2(SiO4)3:Ce3+ phosphor is used for orange light emission, then the light emission peak wavelength is suitable, but temperature quenching is significant leading to low efficiency
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the phosphor material. Specifically, it replaces part of the calcium (Ca) in Lu2CaMg2(SiO4)3 with magnesium (Mg) to create Lu2(Ca1-xMgx)Mg2(SiO4)3, where x ranges from 0.03 to 0.3. This compositional parameter adjustment reduces temperature quenching while maintaining the orange light emission peak wavelength, thereby resolving the contradiction between suitable emission wavelength and temperature stability.
Solution Approach 2:
The patent creates a composite phosphor material by combining multiple elements (Lu, Ca, Mg, Si, O, Ce) in a specific garnet structure. The composite material Lu2(Ca1-xMgx)Mg2(SiO4)3 integrates the beneficial properties of different elements: Lu provides the base structure, Ca and Mg together optimize the emission characteristics and reduce temperature quenching, and Ce3+ serves as the emission center. This composite approach resolves the contradiction by achieving both suitable wavelength and reduced temperature sensitivity.
2Illumination intensity
If the light emission wavelength is increased beyond 585 nm, then orange light emission is achieved, but light emission efficiency does not reach practical level
Solution Approach 1:
The patent changes the compositional parameters by introducing magnesium substitution for calcium in the garnet structure. This parameter modification shifts the emission wavelength to the orange region (beyond 585 nm) while simultaneously improving the light emission efficiency to practical levels by reducing temperature quenching effects, thus resolving the contradiction between wavelength and efficiency.
3Temperature
If temperature of the phosphor rises, then operational conditions are met, but light emission efficiency decreases due to temperature quenching
Solution Approach 1:
The patent modifies the material composition parameters by replacing part of calcium with magnesium in the Lu2CaMg2(SiO4)3 structure. This compositional change alters the thermal properties of the phosphor, reducing temperature quenching and maintaining high light emission efficiency even at elevated operational temperatures, thereby resolving the contradiction between temperature tolerance and efficiency maintenance.
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 significantly reduces temperature quenching while maintaining the light emission peak wavelength within a desired range, enhancing the internal quantum efficiency and stability of the phosphor, particularly in orange light emission, thus improving the performance of light emitting devices.
Implementation Method 1
the phosphor is a compound that radiates fluorescence by being given a stimulation such as an ultraviolet ray
Implementation Method 2
temperature quenching of the (Y,Gd)3Al2(AlO4)3:Ce3+ phosphor is increased as the wavelength of the light color to be radiated thereby is increased
Data Source
AI summary
A phosphor is a phosphor composed by containing Ce3+ as an emission center in a matrix garnet compound having a garnet structure. Then, in the matrix garnet compound, a part of Ca that composes a crystal of Lu2CaMg2(SiO4)3 is replaced by Mg. Moreover, a light emitting device includes the above-mentioned phosphor. In this way, it is possible to provide a garnet phosphor in which temperature quenching is reduced without largely shifting the light emission peak wavelength from that of a Lu2CaMg2(SiO4)3:Ce3+ phosphor, and to provide a light emitting device using the garnet phosphor.