Solution Process for Fabricating High-performance Organic Thin-film Transistors

Patent metadata

Field	Value
Publication number	US-2017200895-A1
Application number	US-201715401035-A
Country	US
Kind code	A1
Filing date	Jan 8, 2017
Priority date	Jan 8, 2016
Publication date	Jul 13, 2017
Grant date	—

Abstract

The present invention relates to a solution or ink composition for fabricating high-performance thin-film transistors. The solution or ink comprises an organic semiconductor and a mediating polymer such as polyacrylonitrile, polystyrene, or the like or mixture thereof, in an organic solvent such as chlorobenzene or dichlorobenzene. The percentage ratio by weight of semiconductor:mediating polymer ranges from 5:95 to 95:5, and preferably from 20:80 to 80:20. The solution or ink is used to fabricate via solution coating or printing a semiconductor film, followed by drying and thermal annealing if necessary to provide a channel semiconductor for organic thin-film transistors (OTFTs). The resulting OTFT device with said channel semiconductor has afforded OTFT performance, particularly field-effect mobility and current on/off ratio that are superior to those OTFTs with channel semiconductors fabricated without a mediating polymer.

First claim

1 . A solution-based method of fabricating a channel semiconductor for organic thin-film transistors comprising:
dissolving an organic semiconductor in a solvent with a mediating polymer at a percentage ratio by weight of semiconductor:mediating polymer ranging from 5:95 to 95:5 to produce a solution; and spin casting or printing said solution on a substrate to produce a channel semiconductor; wherein the resulting organic thin-film transistor with said channel semiconductor exhibits a field effect mobility of greater than or equal to 2 cm 2 V −1 s −1 and a current on/off ratio of greater than or equal to 10 5 .

2 . The method according to claim 1 , wherein the percentage ratio by weight of semiconductor:mediating polymer ranges from 20:80 to 80:20.

3 . The method according to claim 1 , wherein the resulting organic thin-film transistor with said channel semiconductor has a field effect mobility of greater than or equal to 5 cm 2 V −1 s −1 and a current on/off ratio of greater than or equal to 10 6 .

4 . The method according to claim 1 , wherein the resulting organic thin-film transistor with said channel semiconductor has a field effect mobility of greater than or equal to 8 cm 2 V −1 s −1 and a current on/off ratio of greater than or equal to 10 6 .

5 . The method according to claim 1 , wherein the percentage ratio by weight of semiconductor:mediating polymer ranging from 30:70 to 70:30.

6 . The method according to claim 1 , wherein the mediating polymer comprises polyacrylonitrile, polystyrene, poly(methyl methacrylate), poly(methyl methacrylate-alt-styrene), polyvinyl chloride, or mixtures thereof.

7 . The method according to claim 1 , wherein the semiconductor comprises a polymer semiconductor including a diketopyrrolopyrrole-based polymer or regioregular poly(3-hexylthiophene), or a mixture thereof.

8 . The method according to claim 1 , wherein the semiconductor comprises a polymer represented by the following formula:

9 . The method according to claim 1 , wherein the semiconductor comprises one or more organic small molecular compound.

10 . The method according to claim 1 , further comprising drying with thermal annealing after spin casting or printing of solution on a substrate.

11 . The method according to claim 1 , wherein the substrate comprises a metalized plastic substrate coated with a thin layer of metal oxide.

12 . The method according to claim 1 , wherein the metal oxide is aluminum oxide or hafnium oxide.

13 . An organic thin film transistor (OTFT) device having an organic semiconductor-based channel, the OTFT device comprising:
a channel comprising an organic semiconductor crystallized within a mediating polymer in the OTFT device on a substrate, the mediating polymer selected from polyacrylonitrile, polystyrene, poly(methyl methacrylate), poly(methyl methacrylate-alt-styrene), polyvinyl chloride, or a mixture thereof at a percentage ratio by weight of semiconductor:mediating polymer ranging from 5:95 to 95:5; wherein the OTFT device has a field effect mobility of greater than or equal to 2 cm 2 V −1 s −1 and a current on/off ratio of greater than or equal to 10 5 .

14 . The OTFT device of claim 13 , wherein the semiconductor is selected from a diketopyrrolopyrrole-based polymer or regioregular poly(3-hexylthiophene), or a mixture thereof.

15 . The OTFT device of claim 13 , wherein the semiconductor comprises a polymer represented by the following formula:

16 . The OTFT device of claim 13 , wherein the substrate comprises a metalized plastic coated with a thin layer of metal oxide.

17 . The OTFT device of claim 13 , comprises said channel semiconductor of an organic semiconductor crystallized in the mediating polymer has a field effect mobility of greater than or equal to 5 cm 2 V −1 s −1 and a current on/off ratio of greater than or equal to 10 6 .

18 . The OTFT device of claim 13 , comprises said channel semiconductor of an organic semiconductor crystallized in the mediating polymer has a field effect mobility of greater than or equal to 8 cm 2 V −1 s −1 and a current on/off ratio of greater than or equal to 10 6 .

19 . The OTFT device of claim 13 , wherein the percentage ratio by weight of semiconductor:mediating polymer ranges from 20:80 to 80:20.

Assignees

• Univ Hong Kong Baptist Univ

Inventors

• Ong Beng Soon
• Lei Yanlian

Classifications

• C08G2261/3243

  containing one or more sulfur atoms as the only heteroatom, e.g. benzothiophene · CPC title

• C08G2261/124

  alternating · CPC title

• C08G2261/92

  TFT applications · CPC title

• C09D165/00

  Coating compositions based on macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain (C09D107/00 - C09D157/00, C09D161/00 take precedence); Coating compositions based on derivatives of such polymers · CPC title

• C09D133/12

  Homopolymers or copolymers of methyl methacrylate · CPC title