Photovoltaic cell with spacers

1. A photovoltaic cell, comprising:

a first electrically conductive layer;

a second electrically conductive layer;

a photoactive material between the first and second electrically conductive layers; and

a plurality of spacers between the photoactive material and the first electrically conductive layer,

wherein the spacers comprise a crossliniking agent for linking the spacers to the photoactive material, the spacers are not disposed in the photoactive material, the spacers are not in contact with the first electrically conductive layer, and the spacers are not in contact with the second electrically conductive layer.

2. The photovoltaic cell of claim 1 , wherein the spacers are configured to prevent contact between the first electrically conductive layer and the photoactive material when the photovoltaic cell is wrapped around a cylinder having a radius of about 1 inch or less.

3. The photovoltaic cell of claim 1 , wherein the photoactive material comprises titania, and the crosslinking agent is a titania crosslinking agent.

4. The photovoltaic cell of claim 3 , wherein the crosslinking agent is Ti(O-Alkyl) 4 or a polymer thereof.

5. The photovoltaic cell of claim 1 , further comprising a charge carrier layer between the photoactive material and the second electrically conductive layer.

6. The photovoltaic cell of claim 5 , wherein the spacers are disposed in the charge carrier layer.

7. The photovoltaic cell of claim 1 , wherein the first electrically conductive layer is a mesh electrode.

8. The photovoltaic cell of claim 7 , wherein the second electrically conductive layer is a mesh electrode.

9. The photovoltaic cell of claim 1 , wherein at least one of the first and second electrically conductive layers comprises an electrically conductive material selected from the group consisting of copper, aluminum, indium, gold, palladium, titanium, platinum, stainless steel, indium tin oxide, tin oxide, fluorine-doped tin oxide and combinations thereof.

10. The photovoltaic cell of claim 1 , wherein the photoactive material comprises a photoactive nanoparticle material.

11. The photovoltaic cell of claim 10 , wherein the photoactive nanoparticle material comprises a material selected from the group consisting of TiO 2 , SrTiO 3 , CaTiO 3 , ZrO 2 , WO 3 , La 2 O 3 , Nb 2 O 5 , SnO 2 , sodium titanate, cadmium selenide (CdSe), cadmium suiphide, potassium niobate, and combinations thereof.

12. The photovoltaic cell of claim 10 , wherein the photoactive nanoparticle material further comprises a dye.

13. The photovoltaic cell of claim 1 , wherein the photoactive material comprises an electron donor material and an electron acceptor material.

14. The photovoltaic cell of claim 13 , wherein the electron acceptor material comprises a material selected from the group consisting of fullerenes, organic nanoparticles, inorganic nanoparticles, oxadiazoles, polyoxadiazols, discotic liquid crystals, carbon nanorods, carbon nanotubes, inorganic nanorods, polymers containing CN groups, polymers containing CF 3 groups and combinations thereof.

15. The photovoltaic cell of claim 13 , wherein the electron acceptor material comprises a substituted fullerene.

16. The photovoltaic cell of claim 13 , wherein the electron donor material comprises a material selected from the group consisting of discotic liquid crystals, polythiophenes, polyphenylenes, polyphenylvinylenes, polysilanes, polythienylvinylenes and polyisothianaphthalenes.

17. The photovoltaic cell of claim 13 , wherein the electron donor material comprises poly(3-hexylthiophene).

18. The photovoltaic cell of claim 17 , wherein the electron acceptor material comprises a substituted fullerene.

19. A photovoltaic system comprising a plurality of photovoltaic cells of claim 1 .

20. The photovoltaic system of claim 19 , wherein at least some of the plurality of photovoltaic cells are electrically connected.

21. The photovoltaic system of claim 20 , wherein at least some of the electrically connected photovoltaic cells are electrically connected in parallel.

22. The photovoltaic system of claim 20 , wherein at least some of the electrically connected photovoltaic cells are electrically connected in series.

23. The photovoltaic system of claim 20 , wherein at least some of the electrically connected photovoltaic cells are electrically connected to a load.

24. The photovoltaic system of claim 19 , wherein all of the plurality of photovoltaic cells are electrically connected.

25. The photovoltaic system of claim 24 , wherein the photovoltaic cells are electrically connected in parallel.

26. The photovoltaic system of claim 24 , wherein the photovoltaic cells are electrically connected in series.

27. The photovoltaic system of claim 24 , wherein the photovoltaic cells are electrically connected to a load.

28. The photovoltaic system of claim 19 , wherein the photovoltaic cells are electrically connected to a load.

29. The photovoltaic cell of claim 1 , wherein the photoactive material comprises a polymer.

30. The photoactive cell of claim 1 , wherein the photoactive material comprises a fullerene.

31. The photovoltaic cell of claim 1 , wherein the spacers are in a shape selected from the group consisting of spheres, cones, cylinders, pyramids, cubes, rods, sheets, squares, circles, semicircles, triangles, diamonds, ellipses, trapezoids, and combinations thereof.

32. The photovoltaic cell of claim 1 , wherein the spacers are in the shape of spheres.

33. The photovoltaic cell of claim 32 , wherein the spheres have an average diameter of at least about one micrometer.

34. The photovoltaic cell of claim 33 , wherein the spheres have an average diameter of at most about 50 micrometers.

35. The photovoltaic cell of claim 1 , wherein the spacers comprise an electrically insulating material.

36. The photovoltaic cell of claim 1 , wherein the spacers comprise resin or glass.

37. The photovoltaic cell of claim 1 , wherein the spacers are transparent.

38. The photovoltaic cell of claim 1 , wherein the spacers are opaque.

39. A photovoltaic cell, comprising:

a first electrically conductive layer;

a second electrically conductive layer;

a photoactive material between the first and second electrically conductive layers;

a charge carrier material between the photoactive material and the first electrically conductive layer, the charge carrier material comprising an electrolye; and

a mesh between the first and second electrically conductive layers,

wherein the mesh comprises a crosslinking agent for linking the mesh to the photoactive material, the mesh is at least partially disposed in the photoactive material and at least partially disposed in the charge carrier material, the mesh is not in contact with the first electrically conductive layer, and the mesh is not in contact with the second electrically conductive layer.

40. The photovoltaic cell of claim 39 , wherein the mesh comprises a plurality of solid regions and open regions.

41. The photovoltaic cell of claim 40 , wherein the open regions are at least about 10% of the total area of the mesh.

42. The photovoltaic cell of claim 40 , wherein the open regions are at most about 99% of the total area of the mesh.

43. The photovoltaic cell of claim 40 , wherein the solid regions comprise an electrically insulating material.

44. The photovoltaic cell of claim 40 , wherein the open regions are in a shape selected from the group consisting of square, circle, semicircle, triangle, diamond, ellipse, trapezoid, and.

45. The photovoltaic cell of claim 40 , wherein the solid regions are in a shape selected from the group consisting of rectangle, circle, semicircle, triangle, diamond, ellipse, trapezoid, and.

46. The photovoltaic cell of claim 40 , wherein different solid regions have different shapes.

47. The photovoltaic cell of claim 40 , wherein different open regions have different shapes.

48. The photovoltaic cell of claim 39 , wherein the mesh transmits at least about 60% of the incident light.

49. A photovoltaic cell, comprising:

a first electrically conductive layer;

a second electrically conductive layer;

a photoactive material between the first and second electrically conductive layers;

a plurality of spacers between the photoactive material and the first electrically conductive layer; and

a catalyst layer between the spacers and the first electrically conductive layer, the catalyst layer comprising poly(3,4-ethylenedioxythiophene),

wherein the spacers comprise a crosslinking agent for linking the spacers to the photoactive material, the spacers are not disposed in the photoactive material, the spacers are not in contact with the first electrically conductive layer, and the spacers are not in contact with the second electrically conductive layer.