Composite Light-Emitting Material Coating for Stability
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Solution Overview
Problem
Existing light-emitting materials, such as semiconductor nanocrystals, inorganic phosphors, and organic dyes, face efficiency and stability issues due to surface defects, environmental exposure, and energy excitation, leading to reduced luminous efficiency and short lifetimes when used individually or in simple combinations.
Innovation Solution
A composite light-emitting material is created by coating the surfaces of inorganic phosphors, semiconductor nanocrystals, and organic dyes with transparent metal oxides or polymers, forming a core-shell structure that stabilizes emission properties and enhances energy transfer, thereby improving luminous efficiency and extending the material's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If semiconductor nanocrystals are used as light-emitting materials, then quantum confinement effect can be achieved to change band gap energy, but surface defects increase due to large surface area which lowers luminous efficiency
Solution Approach 1:
The patent combines semiconductor nanocrystals with inorganic phosphors and organic dyes to create a composite light-emitting material. The inorganic phosphor particles serve as a stable matrix that supports the nanocrystals, reducing the impact of surface defects on overall luminous efficiency while maintaining the quantum confinement effect for color tuning.
Solution Approach 2:
The inorganic phosphor acts as an intermediary between the semiconductor nanocrystals and the environment. It provides a stable structural framework that protects the nanocrystals from surface degradation while allowing energy transfer to occur, thus mediating between the need for high surface area (for quantum effect) and surface stability.
2Reliability
If inorganic phosphors are used as light-emitting materials, then stable emission properties can be achieved, but emission properties change easily due to surface oxidation and electron accumulation
Solution Approach 1:
The semiconductor nanocrystals and organic dyes act as intermediaries that absorb excitation energy and transfer it to the inorganic phosphor for light emission. This reduces the need for direct electron accumulation on the phosphor surface, minimizing oxidation and charging effects that would otherwise degrade emission stability.
Solution Approach 2:
The patent replaces direct electrical excitation of inorganic phosphors with optical excitation through semiconductor nanocrystals and organic dyes. This substitution of the excitation mechanism reduces electron accumulation on phosphor surfaces, thereby reducing oxidation and maintaining emission stability.
3Use of energy by moving object
If organic dyes are used as light-emitting materials, then high luminous efficiency can be achieved, but material safety is lowered and luminous efficiency decreases significantly due to prolonged exposure to high energy excitation light
Solution Approach 1:
The patent merges organic dyes with inorganic phosphors and semiconductor nanocrystals in a composite structure. The inorganic phosphor provides long-term stability and resistance to photodegradation, while the organic dye contributes high initial luminous efficiency. The semiconductor nanocrystals enable wavelength conversion and protect the organic dye from direct exposure to high-energy excitation light.
4Use of energy by moving object
If two or more light-emitting materials are combined into a single structure through fusion, then luminous efficiency and lifetime can be improved, but the complexity of material structure increases
Solution Approach 1:
The composite light-emitting material is segmented into distinct functional components: semiconductor nanocrystals for wavelength conversion and initial energy absorption, inorganic phosphors for stable light emission and structural support, and organic dyes for enhancing luminous efficiency. Each component performs a specific function, making the complex structure manageable and manufacturable.
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 composite material exhibits superior luminous efficiency, prolonged lifetime, and stable emission properties by preventing surface defects and environmental degradation, while enabling efficient energy transfer and color conversion, outperforming simple mixtures of light-emitting materials.
Implementation Method 1
the semiconductor nanocrystal ('quantum dot') is prepared by pulverizing a semiconductor compound into a nano-sized crystal, which exhibits a quantum confinement effect in a smaller range than the bulk exciton Bohr radius of the semiconductor compound, thereby leading to a change in band gap energy
Implementation Method 2
a composite light-emitting material which is capable of simplifying the procedure for applying the light-emitting material to a light-emitting device and of efficiently regulating the characteristics of the light-emitting device by combining two or more light-emitting materials into a single structure through fusion
Data Source
AI summary
Disclosed herein are a composite light-emitting material, which includes two or more light-emitting materials selected from an inorganic phosphor, a semiconductor nanocrystal and an organic dye in which the surfaces of the two or more light-emitting materials are coated; and a light-emitting device comprising the same, so as to improve the luminous efficiency and lifetime.