Polyarylate Gate Insulating Layer for Organic Thin Film Transistors

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Solution Overview

Problem

Current gate insulating layers for organic thin film transistors face challenges in terms of process complexity, cost, flexibility, and performance, particularly when using inorganic materials, and there is a need for novel organic materials with improved chemical structures to enhance device performance.

Innovation Solution

A composition for forming a gate insulating layer using polyarylate with an ester group on its backbone, which allows for a simpler and less expensive solution process, providing excellent electrical insulation and interfacial characteristics when in contact with the organic semiconductor channel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inorganic insulating layer materials (silicon oxide, silicon nitride, aluminum oxide) are used for the gate insulating layer, then the insulating properties are improved, but the process complexity increases due to vacuum deposition requirements and high process temperature

Engineering Contradiction:

Improveinsulating propertiesVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the material parameter from inorganic to organic (polyarylate), which fundamentally alters the deposition process from vacuum deposition to solution processing. This parameter change enables low-temperature fabrication and eliminates complex vacuum equipment requirements while maintaining sufficient insulating properties for organic thin-film transistor operation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical vacuum deposition system with a chemical solution processing method. Instead of using vacuum pumps and deposition equipment, the gate insulating layer is formed by coating organic material solutions, which can be done using simple techniques like spin-coating or dip-coating at atmospheric pressure

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If inorganic insulating layer materials are used, then the insulating properties are improved, but the flexibility and adaptability to large-area substrates deteriorate due to high process temperature and rigid material properties

Engineering Contradiction:

Improveinsulating propertiesVSAvoidflexibility and large-area applicability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the thermal parameter from high-temperature processing to low-temperature solution processing. The polyarylate gate insulating layer can be fabricated at temperatures compatible with flexible substrates, enabling bending and conformal applications that inorganic materials cannot achieve

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses an organic polymer material (polyarylate) that inherently provides flexibility and conformability. This enables the gate insulating layer to be applied on flexible substrates and large-area surfaces, creating bendable and wearable electronic devices

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If inorganic insulating layer materials are used, then the insulating properties are improved, but the manufacturing cost increases due to vacuum deposition equipment and process requirements

Engineering Contradiction:

Improveinsulating propertiesVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive vacuum deposition equipment with simple solution coating equipment. The gate insulating layer is formed by applying organic material solutions using low-cost techniques, eliminating the need for costly vacuum chambers and deposition systems

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses solution-based organic materials that can be applied in a single step without requiring expensive equipment. The polyarylate can be processed from solution and cured at low temperature, providing a disposable-like simplicity in the manufacturing process

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Ease of manufacture

If conventional organic insulating layer materials are used, then the solution process advantage is improved, but the interfacial characteristics with organic semiconductor channel deteriorate

Engineering Contradiction:

Improvesolution process capabilityVSAvoidinterfacial characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the polyarylate structure to have specific local properties at the interface with the organic semiconductor channel. The ester groups in the polyarylate backbone create favorable interfacial characteristics that enhance carrier injection and transport, while maintaining the overall solution processability of the material

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8057870B2Composition for forming gate insulating layer of organic thin-film transistor and organic thin film transistor using the same

Publication Date: 2011.11.15 LG CHEM LTD

AI summary

The present invention relates to a composition for forming a gate insulating layer of an organic thin film transistor comprising polyarylate, and an organic thin film transistor comprising a gate insulating layer, which is formed using the composition, in contact with an organic semiconductor channel.