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

• US 20170200896A1
• Filed: 03/20/2017
• Published: 07/13/2017
• Est. Priority Date: 01/08/2016
• Status: Active Grant

• Current Assignee: Hong Kong Baptist University
• Original Assignee: Hong Kong Baptist University
• Inventors: Ong, Beng Soon, Lei, Yanlian
• Granted Patent: US 10,454,033 B2
• Time in Patent Office: Days
• CPC Class Codes: B32B 3/10 characterised by a discontinuous layer, i.e. formed of separate pieces of material
• CPC Class Codes: C08G 2261/124 alternating
• CPC Class Codes: C08G 2261/1412 Saturated aliphatic units
• CPC Class Codes: C08G 2261/212 Regioregularity
• CPC Class Codes: C08G 2261/3223 containing one or more sulfur atoms as the only heteroatom, e.g. thiophene
• CPC Class Codes: C08G 2261/3243 containing one or more sulfur atoms as the only heteroatom, e.g. benzothiophene
• CPC Class Codes: C08G 2261/334 containing heteroatoms
• CPC Class Codes: C08G 2261/344 containing heteroatoms
• CPC Class Codes: C08G 2261/364 containing hetero atoms
• CPC Class Codes: C08G 2261/51 Charge transport
• CPC Class Codes: C08G 2261/92 TFT applications
• CPC Class Codes: C08G 61/126 with a five-membered ring containing one sulfur atom in the ring
• CPC Class Codes: C08L 23/06 Polyethene
• CPC Class Codes: C08L 27/06 Homopolymers or copolymers of vinyl chloride
• CPC Class Codes: C08L 33/06 of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
• CPC Class Codes: C08L 33/12 Homopolymers or copolymers of methyl methacrylate
• CPC Class Codes: C08L 33/20 Homopolymers or copolymers of acrylonitrile C08L55/02 takes precedence
• CPC Class Codes: C08L 65/00 Compositions of macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain C08L7/00 - C08L57/00, C08L61/00 take precedence; Compositions of derivatives of such polymers
• CPC Class Codes: C09D 11/106 containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09D 11/107 from unsaturated acids or derivatives thereof
• CPC Class Codes: C09D 11/108 : Hydrocarbon resins
• CPC Class Codes: C09D 11/12 : based on waxes or bitumen
• CPC Class Codes: C09D 11/52 : Electrically conductive inks
• CPC Class Codes: C09D 123/06 : Polyethene
• CPC Class Codes: C09D 125/06 : Polystyrene
• CPC Class Codes: C09D 127/06 : Homopolymers or copolymers of vinyl chloride
• CPC Class Codes: C09D 133/12 : Homopolymers or copolymers of methyl methacrylate
• CPC Class Codes: C09D 133/20 : Homopolymers or copolymers of acrylonitrile C09D155/02 takes precedence
• CPC Class Codes: C09D 165/00 : 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 Class Codes: C09D 5/24 : Electrically-conducting paints conductive materials H01B1/00
• CPC Class Codes: C09D 7/65 : macromolecular C09D7/41-C09D7/48 take precedence
• 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 10/476 : comprising at least one organic layer and at least one inorganic layer
• CPC Class Codes: H10K 10/484 : characterised by the channel regions
• CPC Class Codes: H10K 10/488 : the channel region comprising a layer of composite material having interpenetrating or embedded materials, e.g. a mixture of donor and acceptor moieties, that form a bulk heterojunction
• CPC Class Codes: H10K 71/12 : using liquid deposition, e.g. spin coating
• CPC Class Codes: H10K 71/13 : using printing techniques, e.g. ink-jet printing or screen printing
• CPC Class Codes: H10K 71/40 : Thermal treatment, e.g. annealing in the presence of a solvent vapour
• CPC Class Codes: H10K 85/111 : comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
• CPC Class Codes: H10K 85/113 : Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
• CPC Class Codes: H10K 85/141 : comprising aliphatic or olefinic chains, e.g. poly N-vinylcarbazol, PVC or PTFE
• CPC Class Codes: H10K 85/151 : Copolymers
• CPC Class Codes: H10K 85/621 : Aromatic anhydride or imide compounds, e.g. perylene tetra-carboxylic dianhydride or perylene tetracarboxylic di-imide
• CPC Class Codes: Y10T 428/24802 : Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

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.

Claims

1. A solution-based method of fabricating a channel semiconductor for organic thin-film transistors at room temperature comprising:

dissolving at least one organic semiconductor and at least one hydrocarbon binder in at least one solvent to produce a solution;

coating or printing said solution on a substrate to produce a coated substrate; and

drying said coated substrate at room temperature to produce a channel semiconductor film on the substrate.

2. The method according to claim 1 wherein the at least one hydrocarbon binder is selected from hydrocarbon compounds represented by a formula, C_mH_2m+2, wherein m is a positive integer ranging from about 10 to over 100.

3. The method according to claim 1 wherein the at least one hydrocarbon binder is selected from straight-chain aliphatic hydrocarbons or aliphatic hydrocarbons.

4. The method according to claim 3 wherein the aliphatic hydrocarbons are aliphatic hydrocarbons containing aromatic substituents selected from a phenyl, tolyl, or their derivatives.

5. The method according to claim 1 wherein the solution further comprises other additives selected from other hydrocarbon derivatives, aromatic compounds, or polymer additives other than the at least one hydrocarbon binder.

6. The method according to claim 1 wherein the at least one hydrocarbon binder comprises a hydrocarbon binder with a formula of CH₃—

(CH₂)_x—

CH₃ or CH₃—

C_xH_2x—

CH₃ wherein x is a positive integer ranging from 8 to over 100.

7. The method according to claim 1 wherein the at least one hydrocarbon binder comprises paraffin wax, household candle wax, polyethylene wax or Parafilm wax.

8. The method according to claim 1 wherein the at least one hydrocarbon binder has a melting point above room temperature.

9. The method according to claim 8 wherein the melting point ranges from 30°

C. to over 100°

C.

10. The method according to claim 1 wherein the solution contains at least two hydrocarbon binders each represented by the formula, C_mH_2m+2, wherein m is a positive integer ranging preferably from about 10 to over 100 and wherein one hydrocarbon binder has a melting point ranging from room temperature to about 75°

C., and another has a melting point above 50°

C.

11. The method according to claim 1 wherein the proportion of the at least one hydrocarbon binder in the channel semiconductor composition ranges from 10% to 90% by weight

12. The method according to claim 11 wherein the proportion of the at least one hydrocarbon binder in the channel semiconductor composition ranges from 45% to 70% by weight.

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

14. The method according to claim 1 wherein the at least one organic semiconductor comprises a polymer represented by the following formula:

15. The method according to claim 1 wherein the at least one organic semiconductor comprises one or more organic small molecular compounds.

16. The method according to claim 1 wherein the at least one solvent comprises chlorobenzene or dichlorobenzene.

17. An organic thin-film transistor device wherein at least one channel semiconductor is fabricated using the method according to claim 1.

18. The organic thin-film transistor device according to claim 17 wherein the at least one hydrocarbon binder is selected from hydrocarbon compounds represented by a formula, C_mH_2m+2, wherein m is a positive integer ranging from about 10 to over 100.

19. The organic thin-film transistor device according to claim 17 wherein the at least one hydrocarbon binder is selected from straight-chain aliphatic hydrocarbons or aliphatic hydrocarbons wherein said aliphatic hydrocarbons are selected from aliphatic hydrocarbons including those containing aromatic substituents selected from a phenyl, tolyl, or their derivatives.

20. The organic thin-film transistor device according to claim 17 wherein the proportion of the at least one hydrocarbon binder in the channel semiconductor composition ranges from 10% to 90% by weight.

21. The organic thin-film transistor device according to claim 17 wherein the proportion of the at least one hydrocarbon binder in the channel semiconductor composition ranges from 45% to 70% by weight.

22. The organic thin-film transistor device according to claim 17 wherein the at least one organic semiconductor comprises a polymer semiconductor including a diketopyrrolopyrrole-based polymer or regioregular poly(3-hexylthiophene), or a mixture thereof.

23. The organic thin-film transistor device according to claim 17 wherein the channel semiconductor contains at least two hydrocarbon binders each represented by the formula, C_mH_2m+2, wherein m is a positive integer ranging from about 10 to over 100 and wherein one hydrocarbon binder has a melting point ranging from room temperature to about 75°

C., and another has a melting point above 50°

C.