Semiconductor Nanocrystal-Polymer Composite Ligand Stabilization

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Solution Overview

Problem

Semiconductor nanocrystals used in display devices face aggregation issues due to insufficient compatibility with silicone polymers, leading to loss of organic ligands and decreased device efficiency, necessitating a method to prevent aggregation and stabilize the ligands.

Innovation Solution

A semiconductor nanocrystal-polymer composite is developed, incorporating a polymer with carboxylate anion groups and a metal cation that binds to the nanocrystal surface, stabilizing both the nanocrystal and the polymer, thereby preventing aggregation and enhancing thermal stability and device efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If silicone polymer is used as a matrix resin for dispersing semiconductor nanocrystal, then the nanocrystal can be dispersed in the polymer, but the organic ligand on the nanocrystal surface is lost due to insufficient compatibility, causing aggregation and decreased device efficiency

Engineering Contradiction:
Improvestability of organic ligand on nanocrystal surfaceVSAvoiddevice efficiency
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

A polymer containing carboxylate anion groups is introduced as an intermediary substance between the semiconductor nanocrystal and the silicone polymer matrix. The carboxylate anion groups specifically bind to the surface of the nanocrystal, forming a protective interface layer that prevents direct contact between the incompatible silicone polymer and the organic ligand, thereby preventing aggregation and ligand loss while maintaining dispersion

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure consisting of three components: semiconductor nanocrystal, polymer with carboxylate anion groups, and silicone polymer matrix. This composite material system resolves the incompatibility issue by combining materials with complementary properties, where the intermediate polymer layer provides both stability to the nanocrystal and compatibility with the silicone matrix

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If silicone polymer is used to disperse nanocrystal, then dispersion is achieved, but aggregation occurs due to ligand loss, reducing device efficiency

Engineering Contradiction:
Improvedispersion stability of nanocrystalVSAvoiddevice efficiency
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The polymer with carboxylate anion groups serves as a mediator that maintains stable dispersion of nanocrystals in the silicone polymer matrix. The carboxylate groups bind to the nanocrystal surface, creating a stable interface that prevents aggregation and maintains dispersion stability without compromising device efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical parameters of the polymer matrix by introducing carboxylate anion groups, which alter the interaction characteristics between the polymer and nanocrystal surface. This parameter change enables compatible interaction that prevents aggregation while maintaining dispersion

Inventive Principle:
Principle #35Parameter changes

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 effectively protects semiconductor nanocrystals, improving device efficiency and thermal stability by preventing aggregation and maintaining organic ligand stability, resulting in enhanced luminescence intensity and external quantum efficiency.

Implementation Method 1

a polymer including a plurality of carboxylate anion groups (-COO -

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

The polymer comprises a first carboxylate anion group for binding to the surface of the semiconductor nanocrystal

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

a metal compound including a metal cation which is distinct from the nanocrystal and bindable to a carboxyl group of the plurality of carboxyl groups

Methodology Applied
Scientific EffectIonic bonding: Chemical Bonding

Data Source

PatentEP2584623B1Semiconductor nanocrystal-polymer composite, method of preparing the same, and composite film and optoelectronic device including the same
Publication Date: 2019.02.27 SAMSUNG ELECTRONICS CO LTD
  • EP2584623B1 patent drawingFigure 1
  • EP2584623B1 patent drawingFigure 2
  • EP2584623B1 patent drawingFigure 3

AI summary

A semiconductor nanocrystal-polymer composite including a semiconductor nanocrystal, a polymer comprising a plurality of carboxylate anion groups (-COO-) bindable to a surface of the semiconductor nanocrystal, and a metal cation bindable to a carboxylate anion group of the plurality of carboxylate anion groups.