Gel electrolytes for dye sensitized solar cells
View Patent ↗Replacing liquid electrolytes with solid or quasi-solid electrolytes facilitates the production of photovoltaic cells using continuous manufacturing processes, such as roll-to-roll or web processes, thus creating inexpensive, lightweight photovoltaic cells using flexible plastic substrates.
1. An electrolyte composition adapted for use in a solar cell, the electrolyte composition comprising:
an ionic liquid comprising an imidazolium iodide;
a gelling compound comprising a metal ion; and
an organic compound cross-linked by the metal ion at a plurality of sites;
wherein
the organic compound is selected from the group consisting of poly(4-vinyl pyridine), poly(2-vinyl pyridine), polyurethanes, and polyamides; and
the composition is a gel.
2. The electrolyte composition of claim 1 , wherein the metal ion comprises a lithium ion.
3. The electrolyte composition of claim 1 , wherein the gelling compound is a lithium salt.
4. The electrolyte composition of claim 3 , wherein the lithium salt has the formula LiX, wherein X is an iodide, bromide, chloride, perchlorate, thiocyanate, trifluoromethyl sulfonate, or hexafluorophosphate.
5. The electrolyte composition of claim 2 , further comprising iodine at a concentration of at least about 0.05 M.
6. The electrolyte composition of claim 1 , further comprising:
an amount of water ranging from 0 to 10 wt %;
iodine at a concentration of at least 0.05 M; and
optionally, methyl-benzimidazole;
wherein the composition comprises at least about 90 wt % of the ionic liquid.
7. The electrolyte composition of claim 6 , wherein the ionic liquid is selected from the group consisting of butylmethylimidazolium iodide, propylmethylimidazolium iodide, hexylmethylimidazolium iodide and combinations thereof.
8. The electrolyte composition of claim 6 , wherein the gelling compound is LiCl.
9. The electrolyte composition of claim 8 , wherein the amount of LiCl is between about 1 wt % LiCl and 6 wt % LiCl.
10. The electrolyte composition of claim 8 , wherein the amount of LiCl is at least about 1 wt % LiCl.
11. The electrolyte composition of claim 8 , wherein the amount of LiCl is less than about 6 wt % LiCl.
12. The electrolyte composition of claim 6 , wherein the gelling compound is LiI.
13. The electrolyte composition of claim 12 , wherein the amount of LiI is between about 1 wt % LiI and 6 wt % LiI.
14. The electrolyte composition of claim 12 , wherein the amount of LiI is at least about 1 wt % LiI.
15. The electrolyte composition of claim 12 , wherein the amount of LiI is less than about 6 wt % LiI.
16. A method of gelling an electrolyte solution for use in a dye-sensitized solar cell, the method comprising the steps of:
providing an organic compound, an ionic liquid comprising an imidazolium iodide, and a gelling compound comprising a metal ion; and
mixing the organic compound with the gelling compound thereby forming a gel comprising the organic compound cross-linked by the metal ion at a plurality of sites;
wherein the organic compound is selected from the group consisting of poly(4-vinyl pyridine), poly(2-vinyl pyridine), polyurethanes, and polyamides.
17. The method of claim 16 , wherein the steps are performed at a temperature below 50° C.
18. The method of claim 16 , wherein the steps are performed at standard pressure.
19. The method of claim 16 , wherein the electrolyte solution has a gelling rate controlled by changing a concentration of counter ions in the electrolyte solution.
20. The method of claim 16 , wherein the metal ion is a lithium ion.