Quantum Dot Capping Molecules for Polymer Dispersion
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Solution Overview
Problem
The challenge lies in embedding luminescent nano particles, such as quantum dots, into silicone-based polymers without aggregation, which typically results in phase separation and reduced quantum yields and light transparency due to the low photochemical stability of conventional capping molecules and their incompatibility with high Tg polymers like PDMS and Silres.
Innovation Solution
Development of new capping molecules with a first functional group that binds to the quantum dots and a second functional group that is miscible or reactive with the polymer precursor, allowing for uniform dispersion of luminescent nano particles within silicone polymers, forming stable and transparent thin films with high thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capping molecules are used to coat quantum dots, then the quantum dots can be initially stabilized, but the capping molecules aggregate in high Tg polymers like PDMS and Silres, leading to phase separation and reduced quantum yields
Solution Approach 1:
The patent modifies the chemical parameters of the capping molecules by introducing polymer-compatible functional groups (such as silane groups that can react with PDMS or Silres). This parameter change allows the capping molecules to remain stable and compatible with high Tg polymers, preventing aggregation and phase separation while maintaining high quantum yields.
Solution Approach 2:
The patent creates a composite capping molecule structure that combines the quantum dot-binding functional group with polymer-compatible functional groups. This composite structure enables simultaneous compatibility with both quantum dots and high Tg polymers like PDMS and Silres, resolving the aggregation issue while preserving optical properties.
2Temperature
If quantum dots are embedded in high Tg polymers like PDMS and Silres, then thermal stability and light transparency are improved, but the quantum dots aggregate due to incompatibility with conventional capping molecules
Solution Approach 1:
The patent changes the chemical composition parameters of the capping molecules to include functional groups that are compatible with high Tg polymers. This allows the quantum dots to be uniformly dispersed in thermally stable polymers like PDMS and Silres without aggregation, maintaining both thermal stability and compositional homogeneity.
Solution Approach 2:
The modified capping molecules act as intermediaries between the quantum dots and the high Tg polymer matrix. These intermediary molecules provide chemical compatibility between the inorganic quantum dots and organic polymers, enabling uniform dispersion while preserving the thermal stability benefits of the polymer matrix.
3Ease of manufacture
If conventional capping molecules are used, then quantum dots can be synthesized, but the capping molecules show low photochemical stability and sensitivity in air
Solution Approach 1:
The patent modifies the chemical structure of the capping molecules by incorporating photochemically stable functional groups that are also compatible with high Tg polymers. This parameter change maintains synthesis feasibility while dramatically improving photochemical stability and air resistance, allowing the quantum dot-polymer composites to maintain high quantum yields under operational conditions.
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 process enables the formation of highly transparent and thermally stable luminescent polymer composites with improved quantum yields, overcoming the limitations of aggregation and phase separation in previous nano particle-polymer systems, and can be used in lighting applications for efficient light conversion.
Implementation Method 1
capping molecules comprising a first functional group and a second functional group, wherein the first functional group is configured to bind to the outer surface of the quantum dot
Implementation Method 2
a plurality of first quantum dots for generating wavelength-converted light by converting wavelength of light from the light emitting source
Data Source
AI summary
The invention provides a process for the production of a solid polymer with embedded luminescent nano particles, comprising (1) mixing luminescent nano particles with an outer surface coated with capping molecules comprising a first functional group and a second functional group and a precursor of a solid polymer, and (2) allowing the solid polymer to be formed; wherein the first functional group is configured to bind to the outer surface of the quantum dot and the second functional group is miscible with the precursor of the solid polymer and/or is able to react with the precursor of the solid polymer. The invention also provides a luminescent polymeric article comprising a solid polymer with in the polymer article embedded luminescent nano particles with an outer surface coated with capping molecules comprising a first functional group and a second functional group.