Displays with integrated photovoltaic cells

1. An article, comprising:

a substrate;

a photovoltaic cell supported by the substrate; and

a display between the substrate and the photovoltaic cell,

wherein the article is configured so that:

when the display is transparent or semitransparent, light can pass through the display so that the light interacts with the photovoltaic device to generate electricity;

electricity generated by the photovoltaic cell can be transported to the display to make the display non-transparent to the light; and

when the display is non-transparent, the display blocks the light from reaching the photovoltaic device to stop the photovoltaic device from generating electricity.

2. The article of claim 1 , wherein the article is flexible.

3. The article of claim 1 , wherein the article has a thickness of at most about 5 mm.

4. The article of claim 1 , wherein the display comprises at least a portion of advertisement, paper, a business card, a magazine, or a book.

5. The article of claim 1 , wherein the display is configured to show a fixed picture, signage, pattern, text, or logo.

6. The article of claim 1 , wherein the display is configured to show an animated picture, signage, pattern, text, or logo.

7. The article of claim 1 , wherein the display comprises a passive matrix.

8. The article of claim 1 , wherein the display comprises an electrophoretic display or an electrochromic display.

9. The article of claim 1 , wherein the photoactive layer comprises an electron donor material and an electron acceptor material.

10. The article of claim 9 , wherein the electron acceptor material comprises a material selected from the group consisting of fullerenes, inorganic nanoparticles, oxadiazoles, discotic liquid crystals, carbon nanorods, inorganic nanorods, polymers containing CN groups, polymers containing CF 3 groups, and combinations thereof.

11. The article of claim 10 , wherein the electron acceptor material comprises a substituted fullerene.

12. The article of claim 9 , wherein the electron donor material comprises a material selected from the group consisting of discotic liquid crystals, polythiophenes, polyphenylenes, polyphenylvinylenes, polysilanes, polythienylvinylenes, and polyisothianaphthalenes.

13. The article of claim 9 , wherein the electron donor material comprises poly(3-hexylthiophene).

14. The article of claim 1 , wherein the photovoltaic cell further comprises a hole blocking layer between the photoactive layer and one of the two electrodes.

15. The article of claim 14 , wherein the hole blocking layer comprises a material selected from the group consisting of LiF, metal oxides and combinations thereof.

16. The article of claim 1 , wherein the photovoltaic cell further comprises a hole carrier layer between the photoactive layer and one of the two electrodes.

17. The article of claim 16 , wherein the hole carrier layer comprises a material selected from the group consisting of polythiophenes, polyanilines, polyvinylcarbazoles, polyphenylenes, polyphenylvinylenes, polysilanes, polythienylenevinylenes, polyisothianaphthanenes and combinations thereof.

18. The article of claim 1 , wherein the article is so configured that it does not require an additional power supply or electronic device for the operation of the display.

19. The article of claim 1 , wherein the article is configured so that, during use, the display blinks.

20. The article of claim 1 , wherein changing the electrical state of the display during use of the article causes the display to blink.

21. A method, comprising:

a) providing an article including a display and a photovoltaic device;

b) passing light through the display so that the light interacts with the photovoltaic device to generate electricity;

c) transporting the electricity to the display to make the display non-transparent to the light; and

d) using the non-transparent display to block the light from reaching the photovoltaic device so that the photovoltaic device stops generating electricity.

22. The method of claim 21 , wherein changing the electrical state of the display changes the display from being transparent or semi-transparent to being non-transparent.

23. The method of claim 22 , wherein changing the electrical state of the display changes the display from being non-transparent to being transparent or semi-transparent.

24. The method of claim 21 , wherein changing the electrical state of the display changes the display from being non-transparent to being transparent or semi-transparent.

25. The article of claim 21 , wherein the article is so configured that it does not require an additional power supply or electronic device for the operation of the display.

26. The method of claim 21 , wherein the display blinks during operation.

27. The method of claim 21 , wherein changing the electrical state of the display causes the display to blink.

28. The method of claim 21 , further comprising:

e) stopping the transport of electricity from the photovoltaic device to the display so that the display becomes transparent or semi-transparent to the light.

29. The method of claim 28 , further comprising:

f) passing light through the display so that the light interacts with the photovoltaic device to provide electricity; and

g) transporting the electricity to the display to make the display non-transparent to the light.

30. The method of claim 21 , wherein the method causes the display to blink.