Blade coating on nanogrooved substrates yielding aligned thin films of high mobility semiconducting polymers

Patent metadata

Field	Value
Publication number	US-10186661-B2
Application number	US-201615058994-A
Country	US
Kind code	B2
Filing date	Mar 2, 2016
Priority date	Mar 2, 2015
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

A method for enhancing charge carrier mobility of a field-effect transistor device. The method comprises generating uniaxial nanogrooves on a substrate and blade coating a solution comprising a semiconducting polymer onto the substrate. The polymer solution is spread onto the substrate in a direction parallel to the nanogrooves and a main-chain axis of the polymer is parallel to the nanogrooves. The semiconducting polymer can be then annealed, so that a polymer film is formed which is layered on top of the substrate, with polymer chains aligned parallel to a direction of charge carrier movement.

First claim

What is claimed is:

1. A method for enhancing charge carrier mobility of a field-effect transistor device comprising a charge carrying semiconducting polymer composition, the method comprising:
generating uniaxial nanogrooves on a substrate; and
blade coating a solution comprising a semiconducting polymer onto the substrate, wherein the polymer solution is spread onto the substrate in a direction parallel to the nanogrooves and a main-chain axis of the polymer is parallel to the nanogrooves;
so that polymer is layered on top of the substrate and aligned parallel to a direction of the nanogrooves, thereby enhancing charge carrier mobility of the semiconducting polymer composition in the field-effect transistor device.

2. The method of claim 1 , wherein the nanogrooves are formed to provide nucleation sites that enhance the growth of fibers within the polymer solution.

3. The method of claim 1 , wherein a tilt, S, of the polymer main-chain axis relative to a normal of the substrate is less than or equal to −0.35 and an orientation, η, of the polymer main-chain axis relative to the alignment direction is greater than or equal to 0.96.

4. The method of claim 2 , wherein the polymer crystallizes to form a fiber having a long-axis and a short-axis, and the main-chain axis of the polymer is parallel to the long-axis of the fiber while π-π stacking is in a direction along the short-axis of the fiber.

5. The method of claim 2 , wherein the uniaxial nanogrooves are at least 100 nm in width.

6. The method of claim 1 wherein the polymer is a donor-acceptor copolymer of a cyclopenta[2,1-b:3,4-b′]dithiophene (CDT) donor unit and a [1,2,5]thiadiazolo[3,4-c]pyridine (PT) acceptor unit.

7. The method of claim 1 wherein blade coating the solution comprises positioning a blade at an at least 60° angle to the substrate and at least 150 μm above the substrate.

8. The method of claim 1 , wherein the polymer solution is blade coated onto the substrate at a rate of at least 0.6 mm/s and at a temperature of at least 80° C.

9. The method of claim 1 , wherein the polymer film is annealed at a temperature of at least 200° C.

10. The method of claim 7 , the annealed polymer film has a thickness between 25-35 nm.

11. The method of claim 1 , wherein the semiconducting polymer is annealed to form a polymer film following casting of the semiconducting polymer onto the nanogrooved substrate.

12. The method of claim 1 , wherein a surface of the substrate is treated so as to attract or repel the polymer solution; and/or a surface of the blade is treated so as to attract or repel the polymer solution.

13. The method of claim 1 , wherein the substrate is maintained at a selected temperature or within a selected temperature range to control aggregation in the solution of the semiconducting polymer.

14. The method of claim 1 , wherein the solid film is subsequently thermally treated to improve the order of the semiconducting polymer.

15. The method of claim 1 , wherein the solution is delivered using slot die coating.

16. A method for forming semiconducting polymer film on a substrate, the method comprising:
blade coating a solution comprising a semiconducting polymer onto a substrate having uniaxial nanogrooves, wherein the solution is spread onto the substrate in a direction parallel to the nanogrooves such that a main-chain axis of polymers within the solution are parallel to the nanogrooves;
so that the semiconducting polymer film is formed on top of the substrate, wherein said film comprises a plurality of polymer fibers aligned parallel to the uniaxial nanogrooves.

17. The method of claim 16 , wherein the uniaxial nanogrooves are at least 25, 50, 75 or 100 nm in width.

18. The method of claim 16 , wherein the substrate material is selected to include nanogrooves having nucleation sites for growth of the polymer fibers within the polymer solution.

19. The method of claim 16 , wherein a tilt, S, of the polymer main-chain axis relative to a normal of the substrate is less than or equal to −0.35 and an orientation, ƒ, of the polymer main-chain axis relative to the alignment direction is greater than or equal to 0.96.

20. The method of claim 19 , wherein the polymer crystallizes to form a fiber having a long-axis and a short-axis, and the main-chain axis of the polymer is parallel to the long-axis of the fiber while π-π stacking is in a direction along the short-axis of the fiber.

Assignees

• Univ California

Inventors

• Patel Shrayesh N
• Kramer Edward J
• Chabinyc Michael L
• Luo Chan
• Heeger Alan J

Classifications

• H01L51/0558

  Electricity · mapped topic

• H01L51/0012

  Electricity · mapped topic

• H01L51/0026

  Electricity · mapped topic

• H01L51/0003 Primary

  Electricity · mapped topic

• H01L51/0043

  Electricity · mapped topic