Synthesis of soluble derivatives of sexithiophene and their use as the semiconducting channels in thin-film field-effect transistors

• US 20020072618A1
• Filed: 01/25/2002
• Published: 06/13/2002
• Est. Priority Date: 07/12/2000
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Ali Afzali-Ardakani, Cherie Renee Kagan, Tricia Lynn Breen
• Inventors: Afzali-Ardakani, Ali, Kagan, Cherie Renee, Breen, Tricia Lynn
• Granted Patent: US 6,825,358 B2
• Time in Patent Office: Days
• US Class Current: 549/6
• CPC Class Codes: C07D 333/24 Radicals substituted by carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals
• CPC Class Codes: C07F 9/655345 the sulfur atom being part of a five-membered ring
• CPC Class Codes: C07F 9/65586 at least one of the hetero rings does not contain nitrogen as ring hetero atom
• CPC Class Codes: H10K 10/464 Lateral top-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 10/466 Lateral bottom-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 10/484 characterised by the channel regions
• CPC Class Codes: H10K 85/113 Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
• CPC Class Codes: H10K 85/655 comprising only sulfur as heteroatom

Abstract

In accordance with the first object of this invention soluble derivatives of sexithiophene in which terminal carbons are substituted with various polar groups such as phosphonic esters, phosphonic acids, phosphonates, carboxylic acids, carboxylates, amines, amides, carbamates, and alcohols, each separated from the terminal thiophene rings by one or more methylene groups, are synthesized. An TFT device in accordance with the second objective of this invention employs films of the above sexithiophene derivatives as the semiconducting component. These organic semiconductors are dissolved in common organic solvents and applied to the surface of a substrate using inexpensive, low-temperature solution-based processing such as spin-coating, dip-coating, drop-casting, or microcontact printing.

Claims

1. A structure comprising a sexthiophene:

where the α

- and ω

-carbons of the terminal thiophene rings are substituted with alkyl groups having a polar functionality at their terminal carbons; and

2. A structure of claim 1, where the alkyl groups on both ends have from one to 10 carbons, preferably from 2-6 carbons.

3. A structure of claim 2 where alkyl groups on the terminal rings are substituted at their terminal carbon atoms by a polar functionality.

4. A structure of claim 3 where the polar functionality is a dialkyl phosphonate group.

5. A structure of claim 3 where the polar functionality is a phosphonic acid group.

6. A structure of claim 3 where the polar functionality is a carboxylic acid group.

7. A structure of claim 3 where the polar functionality is a carboxylic ester group.

8. A structure of claim 3 where the polar functionality is an amino group.

9. A structure of claim 3 where the polar functionality is an amide group.

10. A structure of claim 3 where the polar functionality is a hydroxyl group.

14. A field effect transistor as set forth in claim 11, wherein said organic material is a sexithiophene derivative of claim 1.

11. A field effect transistor comprising:

a source region and a drain region;

a channel layer extending between said source region and said drain region, said channel

layer comprising a semiconducting organic material;

a gate region disposed in spaced adjacency to said channel layer, and

an electrically insulating layer between said gate region and said source region, drain region, and channel layer.

12. A field-effect transistor as set forth in claim 11, where said source region, channel layer and drain region are disposed upon a surface of a substrate, said electrically insulating layer is disposed over said channel layer and extending from said source region to said drain region, and said gate region is disposed over said electrically insulating layer.

13. A field effect transistor as set forth in claim 11, where said gate region is disposed as a gate layer upon a surface of a substrate, said electrically insulating layer is disposed upon said gate layer, and said source region, channel layer, and drain region are disposed upon said electrically insulating layer.

15. A field effect transistor as set forth in claim 14, wherein said sexithiophene is applied from a solution of said sexithiophene in an organic solvent.

16. A field effect transistor as set forth in claim 14, wherein the organic material is applied by high vacuum evaporation techniques.

17. A field effect transistor as set forth in claim 11, where the substrate is a flexible material.

18. A field effect transistor as set forth in claim 11, wherein the substrate is comprised of a plastic material.