High mobility polymer thin-film transistors with capillarity-mediated self-assembly

Patent metadata

Field	Value
Publication number	US-9573158-B2
Application number	US-201414585653-A
Country	US
Kind code	B2
Filing date	Dec 30, 2014
Priority date	Jan 3, 2014
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

Embodiments of the invention include methods and materials for preparing organic semiconducting layers, for example one used in an organic semiconductor device including a substrate with a nanostructured surface and a polymeric semiconductor film overlying the nanostructured surface. Aspects of the invention use capillary action to modulate polymer chain self-assembly on a surface and unidirectional alignment at a critical buried interface where charge carriers migrate between a dielectric and the polymer. By controlling the properties of the surfaces upon which polymers are disposed, artisans can enhance the transistor saturated mobilities of conjugated polymers.

First claim

The invention claimed is:

1. A method of using capillary action to form a composition comprising a plurality of aligned polymer fibers, the method comprising:
depositing a solution comprising polymers onto a first substrate, wherein:
the first substrate comprises a first spacer; and
at least one surface of the first substrate and/or spacer has been treated so as to modulate the capillary action of the solution in contact with the first substrate and/or spacer;

allowing capillary action to modulate the flow of the solution contacting the first substrate and/or spacer; and
evaporating the solution, wherein the evaporation rate is controlled so as to be not more than 0.25 μL/min;
so that a composition comprising a plurality of aligned polymer fibers is formed.

2. The method of claim 1 , wherein the first substrate comprises a second spacer and the method comprises disposing a second substrate on top of the first and second spacers so as to form a sandwich tunnel structure.

3. The method of claim 2 , wherein:
a surface of the first and/or second substrate is treated so as to attract or repel the polymer solution; or
a surface of the first and/or second spacer is treated so as to attract or repel the polymer solution.

4. The method of claim 3 , wherein a surface of the first and/or second substrate is treated by coating the surface with a silane composition.

5. The method of claim 3 , wherein a surface of the first and/or second spacer is treated by coating the surface with a silane composition.

6. The method of claim 1 , further comprising tilting the first substrate such that gravity modulates the flow of the solution.

7. The method of claim 6 , wherein the first substrate is tilted at an angle not more than 15° from a level surface.

8. The method of claim 7 , wherein the first substrate is tilted at an angle of 12.5° from a level surface.

9. The method of claim 6 , wherein the method uses gravity to facilitate the flow of the solution towards a first spacer treated so as to attract the solution.

10. The method of claim 1 , wherein:
the first substrate comprises a plurality of indentations that contact and align the plurality of polymer fibers; and
the plurality of indentations are disposed in a direction that is perpendicular to the first spacer.

11. The method of claim 1 , wherein:
the polymer fibers are formed from conjugated polymers comprising a plurality of donor and acceptor units;
the conjugated polymers are disposed in the fibers such that longitudinal axes of the conjugated polymers within the polymer fibers are substantially aligned along longitudinal axes of the polymer fibers; and
the plurality of directionally aligned polymer fibers are adapted to transport charge between source and drain electrodes in a field effect transistor such that the field effect saturation mobility of the plurality of directionally aligned polymer fibers in the field effect transistor is at least 25 cm 2 /Vs.

12. The method of claim 11 , wherein the conjugated polymers comprise regioregular polymers having a regioregular conjugated main chain section, said regioregular conjugated main chain section having a repeat unit that comprises a pyridine of the structure:

wherein Ar is a substituted or non-substituted aromatic functional group, or Ar is nothing and the valence of the pyridine ring is completed with hydrogen; and
the pyridine is regioregularly arranged along the conjugated main chain section.

13. The method of claim 11 , wherein the conjugated polymers comprise a repeat unit of the following structure:

wherein X is O, S, Se, or N—R where R is H or a substituted or non-substituted alkyl, aryl or alkoxy chain; and Y, Z are independently selected to be H or F.

14. The method of claim 1 , wherein the polymers comprise a fluorine atom.

15. The method of claim 14 , wherein the polymers comprise poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b′]dithiophen-2-yl)-6-fluorobenzo[c][1,2,5]thiadiazole] polymers.

16. A method of using capillary action to form a composition comprising a plurality of aligned polymer fibers, the method comprising:
depositing a solution comprising polymers onto a first substrate, wherein:
the first substrate comprises a first spacer; and
at least one surface of the first substrate and/or spacer has been treated so as to modulate the capillary action of the solution in contact with the first substrate and/or spacer;

allowing capillary action to modulate the flow of the solution contacting the first substrate and/or spacer; and
evaporating the solution, wherein the evaporation rate is controlled so as to be not more than 4×10 −3 μLmin −1 mm −2 ;
so that a composition comprising a plurality of aligned polymer fibers is formed.

17. The method of claim 16 , wherein the polymers comprise a fluorine atom.

18. The method of claim 17 , wherein the polymers comprise poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b′]dithiophen-2-yl)-6-fluorobenzo[c][1,2,5]thiadiazole] polymers.

19. A method of using capillary action to form a composition comprising a plurality of aligned polymer fibers, the method comprising:
depositing a solution comprising polymers onto a first substrate, wherein:
the first substrate is tilted at an angle not more than 15° from a level surface;
the first substrate comprises a first spacer; and
at least one surface of the first substrate and/or spacer has been treated so as to modulate the capillary action of the solution in contact with the first substrate and/or spacer;

allowing capillary action to modulate the flow of the solution contacting the first substrate and/or spacer; and
evaporating the solution;
so that a composition comprising a plurality of aligned polymer fibers is formed.

20. The method of claim 19 , wherein the polymers comprise a fluorine atom.

21. The method of claim 20 , wherein the polymers comprise poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b′]dithiophen-2-yl)-6-fluorobenzo[c][1,2,5]thiadiazole]polymers.

Assignees

• The Regents Of Univ Of California
• Univ California

Inventors

• Luo Chan
• Heeger Alan

Classifications

• B05C9/02 Primary

  for applying liquid or other fluent material to surfaces by single means not covered by groups B05C1/00 - B05C7/00, whether or not also using other means · CPC title

• H01L51/0012

  Electricity · mapped topic

• H01L51/0043

  Electricity · mapped topic

• H01L51/0036

  Electricity · mapped topic

• H10K85/113

  Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene · CPC title