Semiconducting Single-Wall Carbon Nanotube Purification via Selective Removal

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Solution Overview

Problem

Existing methods for producing semiconducting single-walled carbon nanotubes (SWCNTs) face challenges in achieving uniform conductivity, as they often inadvertently damage adjacent semiconducting SWCNTs when attempting to remove metallic SWCNTs due to Joule heat generated during the process.

Innovation Solution

A method involving the application of a macromolecule material layer to cover both metallic and semiconducting SWCNTs, followed by exposure to electromagnetic waves to selectively melt and remove the metallic SWCNTs, while maintaining the semiconducting SWCNTs, or using an electron beam to expose and remove metallic SWCNTs while protecting semiconducting ones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high source-drain voltage is applied to burn out metallic SWCNTs, then metallic SWCNTs are removed, but Joule heat inadvertently burns out adjacent semiconducting SWCNTs

Engineering Contradiction:

Improvepurity of semiconducting SWCNTsVSAvoiddamage to semiconducting SWCNTs

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary substance (sulfuric acid solution or oxidizing solution) that selectively interacts with metallic SWCNTs through electrochemical oxidation. This mediator enables selective removal of metallic SWCNTs without requiring direct application of high voltage current that would generate harmful Joule heat, thus protecting semiconducting SWCNTs from damage while achieving high purity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/electrical approach (applying high voltage current to burn out metallic SWCNTs) with a chemical approach (using electrochemical oxidation in sulfuric acid or oxidizing solutions). This substitution eliminates the harmful Joule heat effect while maintaining the selective removal capability, resolving the contradiction between purification effectiveness and protection of semiconducting SWCNTs

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach allows for the production of high-purity semiconducting SWCNTs without damaging the adjacent semiconducting nanotubes, enabling uniform conductivity and simplifying the manufacturing process for mass production.

Implementation Method 1

exposing the plurality of metallic SWCNTs by melting or decomposing the macromolecule material layer 14 in an environment filled with electromagnetic waves

Methodology Applied

Scientific EffectElectromagnetic wave absorption: Absorption (EM radiation)

Implementation Method 2

using an electron beam to expose and remove metallic SWCNTs while protecting semiconducting ones

Methodology Applied

Scientific EffectElectron beam interaction: Electron Beam

Data Source

PatentUS9136117B2Method for making semiconducting single wall carbon nanotubes

Publication Date: 2015.09.15 HON HAI PRECISION INDUSTRY CO LTD

AI summary

A method for making semiconducting single walled carbon nanotubes (SWCNTs) includes providing a substrate. A single walled carbon nanotube film including metallic SWCNTs and semiconducting SWCNTs is located on the substrate. At least one electrode is located on the single walled carbon nanotube film and electrically connected with the single walled carbon nanotube film. A macromolecule material layer is located on the single walled carbon nanotube film to cover the single walled carbon nanotube film. The macromolecule material layer covering the metallic SWCNTs is removed by an electron beam bombardment method, to expose the metallic SWCNTs. The metallic SWCNTs and the macromolecule material layer covering the semiconducting SWCNTs are removed.