Photovoltaic device
An apparatus includes a substrate; and a photoactive layer disposed on the substrate. The photoactive layer includes an electron acceptor material; an electron donor material; and a material having dipoles.
1. An apparatus comprising:
a substrate; and
a photoactive layer disposed on the substrate, wherein the photoactive layer comprises:
an acceptor layer formed of an electron acceptor material;
a donor layer formed of an electron donor material; and
a dipole layer formed of a material having dipoles and disposed between the acceptor layer and the donor layer.
2. The apparatus of claim 1 , wherein the dipole layer is less than 1 nm thick.
3. The apparatus of claim 1 , wherein the dipole layer is a monomolecular layer.
4. The apparatus of claim 1 , wherein the electron acceptor material includes fullerenes.
5. The apparatus of claim 1 , wherein the dipoles align upon application of a bias electric field.
6. The apparatus of claim 1 , wherein the material having dipoles has a polarization charge density of at least about 5 mC/m 2 .
7. 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 or the electron donor material.
8. The apparatus of claim 7 , wherein the dipoles reduce an offset between the lowest unoccupied molecular orbits of the electron acceptor material and the electron donor material.
9. The apparatus of claim 1 , wherein the material having dipoles comprises a ferroelectric polymer.
10. The apparatus of claim 9 , wherein the material having dipoles includes polyvinylidene fluoride and tetrafluoroethylene.
11. The apparatus of claim 1 , wherein the material having dipoles comprises liquid crystal molecules.
12. The apparatus of claim 1 , wherein at least one of the electron acceptor material or the electron donor material comprises an organic semiconductor material.
13. An apparatus comprising:
a substrate; and
a photoactive layer disposed on the substrate, wherein the photoactive layer is a single layer that includes
an electron acceptor material,
an electron donor material, and
a polarizable material.
14. The apparatus of claim 13 , wherein the polarizable material is configured to cause a shift in an energy level of at least one of the electron acceptor material or the electron donor material.
15. An apparatus comprising:
an electrically conductive substrate;
a photoactive layer disposed on the substrate, wherein the photoactive layer comprises:
an acceptor layer formed of an electron acceptor material,
a donor layer formed of an electron donor material, and
a dipole layer formed of a material having dipoles and disposed between the acceptor layer and the donor layer; and
an electrical contact disposed on the photoactive layer.
16. The apparatus of claim 15 , wherein the material having dipoles is configured to increase an open circuit voltage between the substrate and the electrical contact.
17. The apparatus of claim 15 , wherein the material having dipoles is configured to cause a shift in an energy level of at least one of the electron acceptor material or the electron donor material.
18. The apparatus of claim 15 , wherein the dipoles align upon application of a bias to the polarizable material.
19. The apparatus of claim 15 , wherein the substrate is transparent.
20. The apparatus of claim 15 , wherein at least one of the electron acceptor material or the electron donor material comprises an organic semiconductor material.
21. An apparatus comprising:
an electrically conductive substrate;
a photoactive layer disposed on the substrate, wherein the photoactive layer is a single layer that includes
an electron acceptor material,
an electron donor material, and
a material having dipoles; and
an electrical contact disposed on the photoactive layer.
22. The apparatus of claim 21 , wherein the material having dipoles is configured to cause a shift in an energy level of at least one of the electron acceptor material or the electron donor material.
23. A method comprising:
forming a photoactive layer on an electrically conductive substrate, comprising:
forming an acceptor layer including an electron acceptor material,
forming a donor layer including an electron donor material, and
forming a dipole layer including a material having dipoles between the acceptor layer and the donor layer;
forming an electrical contact on the photoactive layer; and
applying an electrical bias to the material having dipoles.
24. The method of claim 23 , wherein applying an electrical bias to the material having dipoles includes causing dipoles to align.
25. The method of claim 23 , 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.
26. The method of claim 23 , wherein at least one of the electron acceptor material or the electron donor material is an organic semiconductor material.
27. A method comprising:
forming a photoactive layer on an electrically conductive substrate, comprising forming a single layer that includes
an electron acceptor material,
an electron donor material, and
a material having dipoles;
forming an electrical contact on the photoactive layer; and
applying an electrical bias to the material having dipoles.
28. The method of claim 27 , wherein applying an electrical bias to the material having dipoles includes causing dipoles to align.