Organic thin film transistors and the use thereof in sensing applications

1. An organic thin film transistor based sensor device, the device including:

(i) a gate electrode;

(ii) a dielectric layer;

(iii) a semiconducting layer including at least one organic compound;

(iv) a source electrode;

(v) a drain electrode;

(vi) a substrate; and

(vii) an enzyme located in, or forming part of any one of (i)-(vi),

wherein the device has top gate bottom contact configuration such that the gate electrode is disposed above the dielectric layer, and the dielectric layer is disposed above the semiconducting layer, and wherein the gate electrode comprises a porous matrix comprising a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer.

2. The device of claim 1 , wherein the semiconducting layer is disposed above and in between the source electrode and the drain electrode.

3. The device of claim 1 , wherein the source electrode and the drain electrode are disposed above the substrate.

4. The device of claim 1 , wherein the sulfonated tetrafluoroethylene-based fluoropolymer-copolymer is a copolymer comprising a tetrafluoroethylene backbone and perfluoroalkyl ether groups terminated with sulfonate groups.

5. The device of claim 4 , wherein the sulfonated tetrafluoroethylene-based fluoropolymer-copolymer is ethanesulfonic acid, 2-[1-[difluoro[(1,2,2-trifluoroethenyl)oxy]methyl]-1,2,2,2-tetrafluoroethoxy]-1,1,2,2-tetrafluoro-, polymer with 1,1,2,2-tetrafluoroethene.

6. The device of claim 1 , wherein the dielectric layer comprises poly(4-vinylphenol) or lithium perchlorate-doped poly(4-vinylpyridine).

7. The device of claim 1 , wherein the enzyme is located in, or forms part of, the gate electrode.

8. The device of claim 1 , wherein the enzyme is located in, or forms part of, the dielectric layer.

9. The device of claim 1 , wherein the at least one organic compound is poly(3-hexyl-thiophene).

10. The device of claim 1 , wherein the semiconducting layer has a thickness between about 5 nm and about 500 nm.

11. The device of claim 1 , wherein the dielectric layer has a thickness between about 50 nm and 750 nm.

12. The device according to claim 1 , wherein the enzyme is glucose oxidase.

13. A device according to claim 1 , wherein the gate electrode further comprises glucose oxidase, the gate electrode being disposed above, and in direct contact with, a dielectric layer, the dielectric layer being disposed above, and in direct contact with, a semiconducting layer, the semiconducting layer being disposed above and in between a source electrode and a drain electrode, and in direct contact with, the source electrode and the drain electrode, the source electrode and the drain electrode being disposed above, and in direct contact with, a substrate.

14. A method for preparing a device as defined in claim 1 comprising:

(a) depositing the source electrode and the drain electrode over the substrate;

(b) depositing the semiconducting layer comprising at least one organic compound over the source electrode and the drain electrode;

(c) depositing the dielectric layer over the semiconducting layer;

(d) depositing the gate electrode over the dielectric layer,

wherein the enzyme is introduced into the device as part of any one or more of steps a) to d).

15. The method of claim 14 , wherein step c) comprises forming a mixture of a dielectric material and the enzyme and depositing the mixture over the semiconducting layer to form the dielectric layer.

16. The method of claim 14 , wherein step d) comprises forming a mixture of a porous matrix and the enzyme and depositing the mixture over the dielectric layer to form the gate electrode.

17. Use of the device of claim 1 , for sensing a compound in a sample/analyte.

18. A method for determining a concentration or an amount of a compound in a sample/analyte comprising the compound, the method comprising the following steps:

a) providing a device as claimed in claim 1 ;

b) applying a gate voltage and a drain voltage to the device;

c) contacting the sample/analyte with the device;

d) detecting drain current; and

e) determining the concentration or the amount of the compound based on the magnitude of the drain current.

19. The device of claim 1 , wherein the gate electrode comprises the enzyme.