Luminescent Particles Double Encapsulation Stability
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Solution Overview
Problem
Current luminescent inorganic nanoparticles used in display and lighting devices lack long-term stability due to inadequate protection against environmental deteriorating species, leading to decreased photoluminescence quantum yield and photobleaching, especially when deposited on LEDs.
Innovation Solution
The development of luminescent particles with a double encapsulation method, where nanoparticles are dispersed in a second inorganic material within a first material, providing enhanced protection and stability, and allowing for better light scattering and compliance with ROHS requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nanoparticles are coated with a protective shell to prevent reactions with deteriorating species, then protection against environmental factors is improved, but the protection is ineffective because the shell is porous allowing access to the nanoparticle surface
Solution Approach 1:
The patent applies nested encapsulation by placing nanoparticles inside a first inorganic material matrix, which is itself embedded within a second inorganic material matrix. This multi-layer nested structure provides progressive barriers that prevent deteriorating species from reaching the nanoparticle surface, resolving the inadequacy of single-layer porous coatings.
Solution Approach 2:
The patent uses composite materials by combining two different inorganic materials with bandgaps ≥3 eV to create a dual-matrix encapsulation system. The first inorganic material forms an inner matrix directly surrounding the nanoparticle, while the second inorganic material forms an outer matrix, creating a composite protective structure that blocks environmental deteriorating species more effectively than single materials.
2Reliability
If multiple inorganic materials with bandgap ≥3 eV are used for double encapsulation, then stability and protection are improved, but the device complexity increases
Solution Approach 1:
Both the first and second inorganic materials serve multiple functions: they provide structural support, act as protective barriers against deteriorating species, enable light scattering, and maintain optical transparency in the UV-blue range due to their bandgaps ≥3 eV. This multi-functionality justifies the added structural complexity by eliminating the need for separate protective layers.
Solution Approach 2:
The patent specifies that both inorganic materials must have bandgaps ≥3 eV, which is a critical parameter change that ensures optical transparency for UV and blue light transmission. This parameter constraint allows the complex dual-matrix structure to function as an integrated protective-optical component rather than requiring additional optical elements.
3Reliability
If nanoparticles are dispersed in inorganic material particles, then protection and stability are improved, but the photoluminescence quantum yield may decrease due to aggregation
Solution Approach 1:
The patent ensures that within the first inorganic material matrix, nanoparticles are dispersed with sufficient spacing to prevent aggregation and maintain high photoluminescence quantum yield. The local environment around each nanoparticle is optimized for optical performance while the overall composite structure provides the required stability and protection.
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 enhances the stability and photoluminescence quantum yield of luminescent particles, preventing degradation from environmental factors and ensuring long-term performance in display and lighting applications while maintaining ROHS compliance.
Implementation Method 1
particles encapsulating nanoparticles in an insulating protective material can act as scatterers in the sub-pixels. This results in the scattering of the light emitted by the light source in all parts of the sub-pixels and then the scattering of the light emitted by sub-pixels so that said light can be emitted in all directions
Implementation Method 2
Semiconductor nanoparticles have a narrow fluorescence spectrum, approximately 30 nm full width at half maximum, and offer the possibility to emit in the entire visible spectrum as well as in the infrared with a single excitation source in the ultraviolet
Implementation Method 3
Luminescent inorganic nanoparticles, especially semiconductor nanoparticles, are known as emissive material... offer the possibility to emit in the entire visible spectrum as well as in the infrared with a single excitation source in the ultraviolet
Data Source
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AI summary
The present invention relates to a luminescent particle (1) comprising a first material (11), wherein the luminescent particle (1) comprises at least one particle (2) comprising a second material (21) and at least one nanoparticle (3) dispersed in said second material (21); wherein the first material (11) and the second material (21) have a bandgap superior or equal to 3 eV; and wherein the luminescent particle (1) is a colloidal particle. The invention also relates to a light emitting material, a support and an optoelectronic device.