Methods of making organic photovoltaic cells having improved heterojunction morphology
View Patent ↗Methods of making a photovoltaic device with an organic liquid precursor having electron donor, electron acceptor, and liquid carrier are provided. The liquid precursor is applied to an electrode. A gas permeable layer/stamp contacts and applies pressure to the organic liquid precursor removing liquid carrier to form a solid active material with uniform interpenetrating network domains of electron donor/acceptor materials. A two-step process is also contemplated. A liquid precursor with either electron donor or acceptor is applied to an electrode, contacted under pressure with a first stamp having a nanoscale pattern, thus forming a solid with a patterned surface. Then, a second liquid precursor with the other of the electron donor or acceptor is applied to the patterned surface, contacted with a second stamp under pressure to form the active material. A transparent conducting electrode with material nanograting can be formed. The methods also include continuous processing, like roll-to-roll manufacturing.
1. A method of making a photovoltaic material by volatilization of a carrier through surface encapsulation and induced alignment, the method comprising:
disposing a liquid precursor between a gas and solvent permeable layer and an electrode, the liquid precursor comprising an organic electron donor material, an organic electron acceptor material, and the carrier comprising a solvent; and
applying pressure to the liquid precursor in a direction from the gas and solvent permeable layer through the liquid precursor and towards the electrode and removing at least a portion of the carrier comprising the solvent through the gas and solvent permeable layer to form a solid photovoltaic material comprising interpenetrating network domains of the organic electron donor material and the organic electron acceptor material.
2. The method of claim 1 , wherein the gas and solvent permeable layer has a surface energy greater than a surface energy of the surrounding environment.
3. The method of claim 1 , wherein the interpenetrating network domains of the organic electron donor material and the organic electron acceptor material are substantially uniform in a direction normal to the electrode.
4. The method of claim 1 , further comprising removing the gas and solvent permeable layer from the solid photovoltaic material.
5. The method of claim 4 , wherein the electrode is a first electrode and further comprising applying a second electrode to at least a portion of a surface of the solid photovoltaic material after removing the gas and solvent permeable layer from the solid photovoltaic material.
6. The method of claim 5 , wherein the second electrode comprises aluminum and lithium fluoride.
7. The method of claim 1 , further comprising applying heat to the solid photovoltaic material to modify crystal morphology of the solid photovoltaic material.
8. The method of claim 1 , further comprising adjusting a thickness of the liquid precursor disposed between the gas and solvent permeable layer and the electrode by changing the amount of the organic electron donor material, the organic electron acceptor material, or the carrier in the liquid precursor or by changing the pressure in the applying step.
9. The method of claim 1 , wherein the disposing step and the applying step are performed using a roll-to-roll process.
10. The method of claim 9 , further comprising adjusting the thickness of the liquid precursor disposed between the gas and solvent permeable layer and the electrode by changing the carrier concentration, applied pressure, and/or rolling speed.
11. The method of claim 1 , wherein the liquid precursor is disposed directly onto the electrode without any buffer layer therebetween.
12. The method of claim 1 , wherein the electrode comprises a transparent conductive electrode (TCE).
13. The method of claim 12 , wherein the TCE comprises an indium-tin-oxide (ITO) electrode; a transparent metal electrode (TME) comprising a metallic nanograting; or an interconnected random network of metallic nanowires.
14. The method of claim 13 , wherein the metallic nanograting comprises silver nanowires.
15. The method of claim 1 , wherein the organic electron donor material comprises poly(3-hexylthiophene) (P3HT) and the organic electron acceptor material comprises [6,6]-phenyl C 61 butyric acid methyl ester (PCBM).
16. A method of making a photovoltaic material by volatilization of a carrier through surface encapsulation and induced alignment, the method comprising:
disposing a liquid precursor between a gas and solvent permeable layer comprising polydimethylsiloxane (PDMS) and an electrode, the liquid precursor comprising an organic electron donor material, an organic electron acceptor material, and the carrier comprising a solvent; and
applying pressure in a direction from the gas and solvent permeable layer to the liquid precursor and towards the electrode and removing at least a portion of the carrier comprising the solvent through the gas and solvent permeable layer through form a solid photovoltaic material comprising interpenetrating network domains of the organic electron donor material and the organic electron acceptor material.
17. The method of claim 16 , wherein the interpenetrating network domains of the organic electron donor material and the organic electron acceptor material are substantially uniform in a direction normal to the electrode.
18. The method of claim 16 , further comprising removing the gas and solvent permeable layer from the solid photovoltaic material.
19. The method of claim 18 , wherein the electrode is a first electrode and further comprising applying a second electrode to at least a portion of a surface of the solid photovoltaic material after removing the gas and solvent permeable layer from the solid photovoltaic material.
20. The method of claim 16 , further comprising applying heat to the solid photovoltaic material to modify crystal morphology of the solid photovoltaic material.
21. The method of claim 16 , wherein the disposing step and the applying step are performed using a roll-to-roll process.
22. The method of claim 16 , wherein the liquid precursor is disposed directly onto the electrode without any buffer layer therebetween.
23. The method of claim 16 , wherein the electrode comprises a transparent conductive electrode (TCE).
24. The method of claim 23 , wherein the TCE comprises an indium-tin-oxide (ITO) electrode; a transparent metal electrode (TME) comprising a metallic nanograting; or an interconnected random network of metallic nanowires.
25. The method of claim 16 , wherein the organic electron donor material comprises poly(3-hexylthiophene) (P3HT) and the organic electron acceptor material comprises [6,6]-phenyl C 61 butyric acid methyl ester (PCBM).
26. A method of making a photovoltaic material by volatilization of a carrier through surface encapsulation and induced alignment, the method comprising:
disposing a liquid precursor between a gas and solvent permeable layer having a flat contact surface and an electrode, the liquid precursor comprising an organic electron donor material, an organic electron acceptor material, and the carrier comprising a solvent; and
applying pressure in a direction from the flat contact surface through the liquid precursor and towards the electrode and removing at least a portion of the carrier comprising the solvent through the gas and solvent permeable layer to form a solid photovoltaic material comprising interpenetrating network domains of the organic electron donor material and the organic electron acceptor material that are substantially uniform in a direction normal to the electrode.
27. The method of claim 26 , further comprising applying heat to the solid photovoltaic material to modify crystal morphology of the solid photovoltaic material.
28. The method of claim 26 , wherein the disposing step and the applying step are performed using a roll-to-roll process.
29. The method of claim 26 , wherein the liquid precursor is disposed directly onto the electrode without any buffer layer therebetween.
30. The method of claim 26 , wherein the electrode comprises a transparent conductive electrode (TCE).
31. The method of claim 26 , wherein the organic electron donor material comprises poly(3-hexylthiophene) (P3HT) and the organic electron acceptor material comprises [6,6]-phenyl C 61 butyric acid methyl ester (PCBM).