Alternating Copolymer for High Mobility Organic Thin Film Transistors

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Solution Overview

Problem

Existing organic thin film transistors (OTFTs) face challenges in achieving high charge mobility and low off-state leakage current, which are essential for commercialization, particularly when using organic semiconductor materials instead of inorganic materials.

Innovation Solution

Development of an alternating copolymer of phenylene vinylene and biarylene vinylene with high solubility and processability, which is used in the organic active layer of OTFTs, enabling high charge mobility and low off-state leakage current through its conductive polymer properties and π-stacking capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If organic semiconductor materials are used in OTFTs, then processability and fabrication cost are improved, but charge mobility and on/off current ratio deteriorate

Engineering Contradiction:

ImproveprocessabilityVSAvoidcharge mobility

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a composite polymer structure combining phenylene vinylene units (for charge transport) with biarylene vinylene units (for solubility and processability). This composite approach allows the material to simultaneously achieve high charge mobility through the phenylene vinylene segments while maintaining excellent processability via the biarylene vinylene segments, resolving the contradiction between ease of manufacture and reliability

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent systematically varies molecular weight, polydispersity index, and chemical composition parameters of the polymer to optimize both charge mobility and processability. By controlling these parameters, the material achieves a balance between electrical performance and fabrication ease, enabling solution processing while maintaining high charge mobility

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If organic semiconductor materials are used in OTFTs, then fabrication cost is reduced, but off-state leakage current increases

Engineering Contradiction:

Improvefabrication costVSAvoidoff-state leakage current

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The alternating copolymer structure combines electron-rich phenylene vinylene units with electron-deficient biarylene vinylene units, creating a balanced electronic structure that reduces off-state leakage current while maintaining low fabrication cost through solution processing

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces specific functional groups and side chains at different positions along the polymer backbone to locally optimize electronic properties. This local quality adjustment allows suppression of off-state leakage current in specific regions while maintaining overall low-cost fabrication capability

Inventive Principle:

Principle #3Local quality

3Area of stationary object

If polymer materials are used in OTFTs, then large area fabrication is enabled, but charge mobility decreases

Engineering Contradiction:

ImproveareaVSAvoidcharge mobility

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent creates a composite polymer system where phenylene vinylene units provide high charge mobility pathways while biarylene vinylene units ensure solubility for large-area solution processing, thus achieving both large area coverage and high charge mobility simultaneously

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The polymer is segmented into alternating units with different functions: phenylene vinylene segments for charge transport and biarylene vinylene segments for solubility. This segmentation allows the material to be processed over large areas via solution methods while maintaining high charge mobility through the conductive phenylene vinylene segments

Inventive Principle:

Principle #1Segmentation

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 alternating copolymer of phenylene vinylene and biarylene vinylene achieves high charge mobility and maintains low off-state leakage current, thereby enhancing the on/off current ratio and stability of OTFTs, making them suitable for various electronic devices.

Implementation Method 1

exhibits partial coplanarity to thus realize amorphous properties and superior π-stacking properties when formed into a film

Methodology Applied

Scientific Effectπ-stacking:

Data Source

PatentUS8039567B2Alternating copolymers of phenylene vinylene and biarylene vinylene, preparation method thereof, and organic thin film transistor comprising the same

Publication Date: 2011.10.18 SAMSUNG ELECTRONICS CO LTD

AI summary

Disclosed herein are an alternating copolymer of phenylene vinylene and biarylene vinylene, a preparation method thereof, and an organic thin film transistor including the same. The organic thin film transistor maintains low off-state leakage current and realizes a high on/off current ratio and high charge mobility because the organic active layer thereof is formed of an alternating copolymer of phenylene vinylene and biarylene vinylene.