Thermally Dissociable Polymer for OLED Film Formation

Solution Overview

Problem

Existing methods for forming organic thin films in organic electroluminescence elements using the wet film-forming method result in lower driving stability and luminescent efficiency due to the presence of long-chain alkyl groups and crosslinkable groups, which hinder charge transport and luminescent performance.

Innovation Solution

A polymer and luminescent-layer material with a thermally dissociable and soluble group are developed, allowing for solubility in coating solvents during film formation and subsequent insolubility after heating, eliminating the need for long-chain alkyl groups and crosslinkable groups, thereby enhancing stability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If long-chain alkyl groups are introduced to improve solubility in coating solvents, then solubility is improved, but charge transport efficiency decreases

Engineering Contradiction:

Improvesolubility in coating solventsVSAvoidcharge transport efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention changes the chemical structure parameters by introducing specific soluble groups (carboxylic acid groups, hydroxyl groups, or amine groups) instead of long-chain alkyl groups. This parameter change maintains solubility in coating solvents while avoiding the harmful effects of long-chain alkyl groups on charge transport efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses temporary soluble groups that can be removed or transformed during the manufacturing process. These groups serve their purpose during coating but are not permanently retained in the final device structure, thus avoiding long-term negative effects on device performance.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Stability of the object's composition

If crosslinkable groups are introduced to improve insolubility after film formation, then insolubility is improved, but luminescent efficiency decreases

Engineering Contradiction:

Improveinsolubility in coating solutionsVSAvoidluminescent efficiency

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The invention extracts or removes the crosslinkable groups from the final material structure. Instead of relying on crosslinking to achieve insolubility, the material uses intrinsic insolubility properties, thus eliminating the harmful crosslinkable groups that would otherwise reduce luminescent efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The soluble groups serve as temporary functional groups during the coating process but are not permanently retained. They fulfill their purpose of enabling solubility during manufacturing but are removed or transformed in the final product, avoiding long-term negative effects on device performance.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If crosslinkable groups are introduced to improve insolubility after film formation, then insolubility is improved, but driving stability decreases

Engineering Contradiction:

Improveinsolubility in coating solutionsVSAvoiddriving stability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The invention extracts or removes the crosslinkable groups from the final material structure. Instead of relying on crosslinking to achieve insolubility, the material uses intrinsic insolubility properties, thus eliminating the harmful crosslinkable groups that would otherwise reduce luminescent efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The soluble groups serve as temporary functional groups during the coating process but are not permanently retained. They fulfill their purpose of enabling solubility during manufacturing but are removed or transformed in the final product, avoiding long-term negative effects on device performance.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 polymer and luminescent-layer material achieve high luminescent efficiency and excellent driving stability with reduced solubility in other solvents, enabling the formation of stable organic electroluminescence elements with low driving voltage.

Implementation Method 1

a polymer which has a thermally dissociable and soluble group

Methodology Applied

Scientific EffectThermal dissociation: Thermolysis

Data Source

PatentUS8795849B2Polymers containing thermally dissociable and soluble groups and the use of such polymers as organic electroluminescent materials

Publication Date: 2014.08.05 MITSUBISHI CHEM CORP

AI summary

A polymer, a luminescent material, and the likes are provided, wherein a film can be formed by a wet film-forming method, the film formed has a high stability, and is capable of being laminated with other layers by a wet film-forming method or another method, which are less decrease in charge transportation efficiency or luminescent efficiency, and attain an excellent driving stability. The polymer has a thermally dissociable and soluble group.