Molded Nanoparticle Phosphor Oxygen Barrier
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Solution Overview
Problem
Semiconductor nanoparticles in light-emitting devices are prone to photo-oxidation due to oxygen migration through the encapsulant, leading to a drop in quantum yield and performance issues, especially when scaled for commercial production.
Innovation Solution
A molded nanoparticle phosphor is created by suspending nanoparticles in a matrix material precursor, which is then molded and coated with a gas barrier material to prevent oxygen and moisture ingress, while allowing for breathability in the LED packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If semiconductor nanoparticles are embedded in an optically clear LED encapsulation medium, then the nanoparticles can be excited by primary light to emit secondary light with characteristic color, but oxygen can migrate through the encapsulant to the nanoparticle surfaces causing photo-oxidation and drop in quantum yield
Solution Approach 1:
The patent applies nested doll by embedding semiconductor nanoparticles within an inner encapsulation medium that is specifically designed to prevent oxygen permeation, which is then nested within the outer optically clear LED encapsulation medium. This multi-layer nested structure allows the nanoparticles to be protected from oxygen while maintaining optical clarity and light-emitting functionality.
Solution Approach 2:
The patent uses composite materials by combining an oxygen-barrier inner encapsulation medium with an optically clear outer encapsulation medium. This composite structure integrates the oxygen-blocking properties of the inner medium with the optical transparency of the outer medium, solving both the photo-oxidation problem and the light transmission requirement simultaneously.
2Ease of manufacture
If conventional phosphors are used in LEDs, then the structure is simple and easy to manufacture, but the emission wavelength cannot be tuned and performance is limited
Solution Approach 1:
The patent applies parameter changes by utilizing semiconductor nanoparticles whose emission wavelength can be precisely tuned by controlling particle size and composition parameters. This allows the LED emission color to be adjusted across a broad spectrum while maintaining a manufacturing process similar to conventional phosphor integration.
3Adaptability or versatility
If nanoparticles are incorporated into LED encapsulant, then emission wavelength tuning is enabled, but oxygen migration through the encapsulant causes photo-oxidation and performance degradation
Solution Approach 1:
The patent protects nanoparticles from oxygen migration by nesting them within an inner encapsulation medium that is specifically designed with low oxygen permeability. This inner protective layer is then nested within the outer optically clear encapsulation medium, creating a nested structure that blocks oxygen while maintaining optical functionality.
Solution Approach 2:
The patent creates an inert environment by selecting an inner encapsulation medium material that inherently resists oxygen permeation, effectively creating an oxygen-free or inert atmosphere around the semiconductor nanoparticles. This protects the nanoparticles from photo-oxidation while allowing the outer medium to provide optical clarity.
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 solution enhances the stability and brightness of light-emitting devices by reducing photo-oxidation and maintaining performance, even on a commercial scale, with improved luminescence intensity and stability of the nanoparticles.
Implementation Method 1
coated with a gas barrier material to prevent oxygen and moisture ingress
Implementation Method 2
The nanoparticles, excited by the primary light of the solid-state LED, emit secondary light, the color of which is characteristic of the particular type and size of the nanoparticles
Implementation Method 3
the nanoparticles will absorb a portion of the blue light and emit red light
Data Source
AI summary
A molded nanoparticle phosphor for light emitting applications is fabricated by converting a suspension of nanoparticles in a matrix material precursor into a molded nanoparticle phosphor. The matrix material can be any material in which the nanoparticles are dispersible and which is moldable. The molded nanoparticle phosphor can be formed from the matrix material precursor/nanoparticle suspension using any molding technique, such as polymerization molding, contact molding, extrusion molding, injection molding, for example. Once molded, the molded nanoparticle phosphor can be coated with a gas barrier material, for example, a polymer, metal oxide, metal nitride or a glass. The barrier-coated molded nanoparticle phosphor can be utilized in a light-emitting device, such as an LED. For example, the phosphor can be incorporated into the packaging of a standard solid state LED and used to down-convert a portion of the emission of the solid state LED emitter.