Photovoltaic device

1. An apparatus comprising:

a substrate; and

a photoactive layer disposed on the substrate, the photoactive layer comprising:

an electron acceptor material;

an electron donor material; and

a material having dipoles, the material having dipoles comprising one or more of a ferroelectric polymer or liquid crystal molecules,

in which a first surface of the material having dipoles is in physical contact with the electron acceptor material and a second surface of the material having dipoles is in physical contact with the electron donor material, the first surface opposite the second surface.

2. The apparatus of claim 1 , wherein the electron acceptor material includes fullerenes.

3. The apparatus of claim 1 , wherein the dipoles align upon application of a bias electric field.

4. The apparatus of claim 1 , wherein the material having dipoles has a polarization charge density of at least about 5 mC/m 2 .

5. The apparatus of claim 1 , wherein the material having dipoles is configured to cause a shift in an energy level of at least one of the electron acceptor material and the electron donor material.

6. The apparatus of claim 5 , wherein the dipoles reduce an offset between the lowest unoccupied molecular orbitals of the electron acceptor material and the electron donor material.

7. The apparatus of claim 1 , wherein the material having dipoles includes polyvinylidene fluoride and tetrafluoroethylene.

8. The apparatus of claim 1 , wherein the material having dipoles comprises liquid crystal molecules.

9. The apparatus of claim 1 , wherein the substrate includes a layer of a conductive material disposed on a support substrate.

10. An apparatus comprising:

an electrically conductive substrate;

a photoactive layer disposed on the substrate, the photoactive layer comprising:

an electron acceptor material;

an electron donor material; and

a material having dipoles, the material having dipoles comprising one or more of a ferroelectric polymer or liquid crystal molecules,

in which the material having dipoles is between the electron acceptor material and the electron donor material; and

an electrical contact disposed on the photoactive layer.

11. The apparatus of claim 10 , wherein the material having dipoles is configured to increase an open circuit voltage between the substrate and the electrical contact.

12. The apparatus of claim 10 , wherein the material having dipoles is configured to cause a shift in an energy level of at least one of the electron acceptor material and the electron donor material.

13. The apparatus of claim 10 , wherein the dipoles align upon application of a bias to the material having dipoles.

14. The apparatus of claim 10 , wherein the substrate is transparent.

15. The apparatus of claim 10 , wherein at least one of the electron acceptor material and the electron donor material comprises an organic semiconductor material.

16. The apparatus of claim 12 , wherein the dipoles reduce an offset between the lowest unoccupied molecular orbitals of the electron acceptor material and the electron donor material.

17. The apparatus of claim 10 , wherein the material having dipoles has a polarization charge density of at least about 5 mC/m 2 .

18. The apparatus of claim 10 , wherein the material having dipoles includes polyvinylidene fluoride and tetrafluoroethylene.

19. A method comprising:

forming a photoactive layer on an electrically conductive substrate, the photoactive layer comprising:

an electron acceptor material;

an electron donor material; and

a material having dipoles, the material having dipoles comprising one or more of a ferroelectric polymer or liquid crystal molecules,

in which the material having dipoles is between the electron acceptor material and the electron donor;

forming an electrical contact on the photoactive layer; and

applying an electrical bias to the material having dipoles.

20. The method of claim 19 , wherein applying an electrical bias to the material having dipoles includes causing dipoles to align.

21. The method of claim 19 , wherein applying an electrical bias to the material having dipoles includes causing an increase in an open circuit voltage between the substrate and the electrical contact.

22. The method of claim 19 , wherein at least one of the electron acceptor material and the electron donor material is an organic semiconductor material.

23. The method of claim 19 , wherein the material having dipoles is configured to cause a shift in an energy level of at least one of the electron acceptor material and the electron donor material.

24. The method of claim 23 , wherein the dipoles reduce an offset between the lowest unoccupied molecular orbitals of the electron acceptor material and the electron donor material.

25. The method of claim 19 , wherein the substrate is transparent.

26. The method of claim 19 , wherein the material having dipoles has a polarization charge density of at least about 5 mC/m 2 .

27. The method of claim 19 , wherein the material having dipoles includes polyvinylidene fluoride and tetrafluoroethylene.

28. An apparatus comprising:

a substrate; and

a photoactive layer disposed on the substrate, the photoactive layer comprising:

an electron acceptor material;

an electron donor material; and

a material having dipoles, the material having dipoles comprising one or more of a ferroelectric polymer or liquid crystal molecules, in which the material having dipoles is between the electron acceptor material and the electron donor material.

29. The apparatus of claim 28 , wherein the dipoles align upon application of a bias to the photoactive layer.

30. The apparatus of claim 28 , wherein at least one of the electron acceptor material and the electron donor material is an organic semiconductor material.

31. The apparatus of claim 28 , wherein the substrate is transparent.

32. The apparatus of claim 28 , wherein the material having dipoles has a polarization charge density of at least about 5 mC/m 2 .

33. The apparatus of claim 28 , wherein the material having dipoles is configured to cause a shift in an energy level of at least one of the electron acceptor material and the electron donor material.

34. The apparatus of claim 33 , wherein the dipoles reduce an offset between the lowest unoccupied molecular orbitals of the electron acceptor material and the electron donor material.

35. The apparatus of claim 28 , wherein the material having dipoles includes polyvinylidene fluoride and tetrafluoroethylene.