Floating evaporative assembly of aligned carbon nanotubes

Patent metadata

Field	Value
Publication number	US-9673399-B2
Application number	US-201615196325-A
Country	US
Kind code	B2
Filing date	Jun 29, 2016
Priority date	Feb 11, 2015
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

High density films of semiconducting single-walled carbon nanotubes having a high degree of nanotube alignment are provided. Also provided are methods of making the films and field effect transistors (FETs) that incorporate the films as conducting channel materials. The single-walled carbon nanotubes are deposited from a thin layer of organic solvent containing solubilized single-walled carbon nanotubes that is continuously supplied to the surface of an aqueous medium, inducing evaporative self-assembly upon contacting a solid substrate.

First claim

What is claimed is:

1. A method of forming a film of aligned s-SWCNTs on a substrate, the method comprising:
(a) partially submerging a hydrophobic substrate in an aqueous medium;
(b) supplying a flow of a liquid solution to the aqueous medium, the liquid solution comprising semiconductor-selective-polymer-wrapped s-SWCNTs dispersed in an organic solvent, whereby the liquid solution spreads into a layer on the aqueous medium at an air-liquid interface and semiconductor-selective-polymer-wrapped s-SWCNTs from the layer are deposited as a film of aligned semiconductor-selective-polymer-wrapped s-SWCNTs on the hydrophobic substrate, wherein the organic solvent in the layer, which is evaporating, is resupplied by the flow of the liquid solution during the formation of the film; and
(c) withdrawing the hydrophobic substrate from the aqueous medium, such that the film of aligned semiconductor-selective-polymer-wrapped s-SWCNTs is grown along the length of the hydrophobic substrate as it is withdrawn from the aqueous medium.

2. The method of claim 1 , wherein the organic solvent comprises chloroform.

3. The method of claim 1 , wherein the organic solvent comprises at least one of dichloromethane, N,N-dimethylformamide, benzene, dichlorobenzene, toluene and xylene.

4. The method of claim 1 , further comprising removing the semiconductor-selective polymer from the aligned semiconductor-selective-polymer-wrapped s-SWCNTs.

5. The method of claim 1 , wherein the semiconductor-selective-polymer-wrapped s-SWCNTs in the film have a degree of alignment of about ±20° or better.

6. The method of claim 1 , wherein the single-walled carbon nanotube linear packing density in the film is at least 40 single-walled carbon nanotubes/μm.

7. The method of claim 1 , wherein the substrate is withdrawn at a rate of at least one mm/min.

8. The method of claim 7 , wherein the concentration of s-SWCNTs in the liquid solution is at least 1 μg/mL and the flow of liquid solution is supplied at a rate of at least 160 μL/min.

9. The method of claim 1 , wherein the semiconductor-selective polymer is a polyfluorene derivative.

10. The method of claim 1 , wherein concentration of SWCNTs in the flow of liquid solution is adjusted as it is supplied to the aqueous medium to control the density of s-SWCNTs along the length of the film.

Assignees

• Wisconsin Alumni Res Found

Inventors

• Arnold Michael Scott
• Evensen Harold T
• Brady Gerald Joseph
• Gopalan Padma
• Joo Yongho

Classifications

• H01L51/0007

  Electricity · mapped topic

• H01L51/0043

  Electricity · mapped topic

• B05D1/18

  performed by dipping · CPC title

• C09D11/106

  containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C01B2202/02

  Single-walled nanotubes · CPC title