Buckled Carbon Nanotube Transistors for Stretchable Electronics

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Solution Overview

Problem

Current stretchable electronic components, such as transistors, primarily rely on silicon materials and have limited success in utilizing other semiconductor materials, hindering the development of unconventional applications like implantable biosensors and wearable electronics.

Innovation Solution

The development of stretchable thin-film transistors with a buckled film of single-walled carbon nanotubes (SWCNTs) as the conductive channel, supported by a stretchable substrate and polymeric dielectric materials, allowing for high tensile strain and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If silicon materials are used for stretchable transistors, then transistor performance is maintained, but stretchability and flexibility are limited

Engineering Contradiction:

ImprovestretchabilityVSAvoidtransistor performance stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the material parameter from traditional silicon to carbon nanotubes, which have inherently different mechanical and electrical properties. This material substitution enables both stretchability and maintained transistor performance, resolving the contradiction between adaptability and reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite structures including carbon nanotube films, elastic substrates, and polymeric dielectric materials. This composite approach combines the electrical performance of carbon nanotubes with the mechanical flexibility of elastic materials, achieving both stretchability and performance stability.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If other semiconductor materials are used instead of silicon, then stretchability is improved, but transistor performance and reliability deteriorate

Engineering Contradiction:

Improvematerial flexibilityVSAvoidtransistor performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the semiconductor material parameter from silicon to carbon nanotubes, which possess both the electrical conductivity needed for reliable transistor operation and the mechanical flexibility required for stretchability. This parameter change resolves the contradiction between material flexibility and transistor performance.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If rigid structures are used for transistors, then manufacturing precision is improved, but ease of operation and stretchability worsen

Engineering Contradiction:

ImprovestretchabilityVSAvoiddevice fabrication accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent employs thin film structures for both the carbon nanotube conducting channel and the polymeric dielectric layer. These thin films provide the necessary flexibility for stretching while maintaining sufficient manufacturing precision through controlled deposition processes, resolving the contradiction between ease of operation and manufacturing precision.

Inventive Principle:

Principle #30Flexible shells and thin films

4Adaptability or versatility

If conventional transistor structures are used, then manufacturing processes are simplified, but adaptability to stretchable applications is limited

Engineering Contradiction:

Improveapplication versatilityVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the transistor structure into distinct functional layers: carbon nanotube conducting channel, polymeric dielectric, elastic substrate, and electrode contacts. This segmentation allows each layer to be optimized independently for its specific function while maintaining overall device simplicity and manufacturability, resolving the contradiction between adaptability and device complexity.

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 transistors exhibit stable performance under high tensile strains, with high on/off ratios, low operating voltages, and robustness through multiple stretch and release cycles, enhancing their suitability for flexible electronic devices.

Implementation Method 1

a conducting channel comprising a buckled film comprising single-walled carbon nanotubes

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a gate dielectric comprising a stretchable polymeric dielectric material disposed over the conducting channel

Methodology Applied

Scientific EffectDielectric insulation: Dielectric

Implementation Method 3

a stretchable substrate comprising an elastic material disposed under the conducting channel

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8987707B2Stretchable transistors with buckled carbon nanotube films as conducting channels

Publication Date: 2015.03.24 WISCONSIN ALUMNI RES FOUND

AI summary

Thin-film transistors comprising buckled films comprising carbon nanotubes as the conductive channel are provided. Also provided are methods of fabricating the transistors. The transistors, which are highly stretchable and bendable, exhibit stable performance even when operated under high tensile strains.