OFET Copolymer Interlayer Adhesion Fluoropolymer

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Solution Overview

Problem

Conventional organic field effect transistors (OFETs) face challenges with the poor processability and structural integrity of fluoropolymers used as gate insulators, leading to issues such as poor adhesion, wrinkling, and cracking, especially during mass production.

Innovation Solution

The introduction of an interlayer between the gate insulator and gate electrode, comprising a copolymer with polar and unpolar repeating units, improves adhesion and structural integrity, enhancing the performance and manufacturability of OFETs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluoropolymers are used as gate insulator material, then charge trapping at the dielectric/OSC interface is reduced and transistor performance is improved, but adhesion to substrate and OSC layer is poor and structural integrity deteriorates

Engineering Contradiction:
Improvetransistor performanceVSAvoidadhesion and structural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies composite materials by combining fluoropolymer with other dielectric materials to create a multi-component gate insulator structure. This composite approach allows the system to simultaneously achieve the low charge trapping properties of fluoropolymers and the improved adhesion/structural integrity of complementary materials, resolving the contradiction between reliability and strength.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces an interlayer as a mediator between the fluoropolymer gate insulator and the OSC layer. This interlayer serves as an intermediate component that improves interfacial adhesion and structural integrity while allowing the fluoropolymer to maintain its charge trapping reduction properties, thus resolving the contradiction without compromising transistor performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If fluoropolymers are used as gate insulator, then processability is improved through solution processing, but adhesion and wetting properties deteriorate

Engineering Contradiction:
ImproveprocessabilityVSAvoidadhesion and wetting
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent uses composite materials combining fluoropolymer with other dielectric components that have better adhesion and wetting properties. This composite structure maintains the solution processability advantage of fluoropolymers while compensating for their poor adhesion through the complementary properties of the other materials in the composite.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The interlayer acts as a mediator that improves adhesion and wetting between the fluoropolymer gate insulator and subsequent layers. This intermediary component enables better manufacturing processability by ensuring proper adhesion during device fabrication while preserving the solution-processing benefits of the fluoropolymer.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If fluoropolymers with low glass temperature are used, then processability is improved, but cracking and wrinkling occur during heating processes

Engineering Contradiction:
ImproveprocessabilityVSAvoidstructural integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials where the fluoropolymer is combined with other dielectric materials that have higher glass temperatures and better thermal stability. This composite structure allows the system to maintain the processability advantages of low-Tg fluoropolymers while the complementary materials prevent cracking and wrinkling during heating processes, thus resolving the contradiction between ease of manufacture and reliability.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2269244B1Top gate organic field effect transistor
Publication Date: 2015.05.27 MERCK PATENT GMBH
  • EP2269244B1 patent drawingFigure 1~2
  • EP2269244B1 patent drawingFigure 3~4
  • EP2269244B1 patent drawingFigure 5a1~5e1

AI summary

The invention relates to an organic electronic (OE) device, in particular a transistor, comprising an interlayer (7) between the gate insulator (4) and the gate electrode (5), to novel processes for preparing the device, and to dielectric materials for use in the interlayer.