Dye-sensitized solar cell including a porous insulation substrate and a method for producing the porous insulation substrate
The present invention relates to a dye-sensitized solar cell including a working electrode ( 1 ), a first conducting layer ( 3 ) for extracting photo-generated electrons from the working electrode, a porous insulation substrate ( 4 ) made of a microfibers, wherein the first conducting layer is a porous conducting layer formed on one side of the porous insulation substrate, a counter electrode including a second conducting layer ( 2 ) arranged on the opposite side of the porous substrate, and electrolyte for transferring electrons from the counter electrode to the working electrode. The porous insulation substrate comprises a layer ( 5 ) of woven microfibers and a layer ( 6 ) of non-woven microfibers disposed on the layer of woven microfibers. The present invention also relates to a method for producing a dye-sensitized solar cell.
1. A method for producing a porous insulation substrate and a porous conducting layer formed on the insulation substrate for a solar cell, the method comprising:
a) producing the porous insulation substrate by
providing a fabric of woven microfibers comprising yarns with holes formed between them,
preparing a fiberstock solution by mixing liquid and microfibers,
covering a first side of the fabric with the fiberstock solution,
draining liquid from the fiberstock solution through the holes in the fabric, and
drying the wet fabric with the microfibers disposed on the fabric,
b) depositing an ink comprising conductive particles on one side of the insulation substrate to form a porous conducting layer, and
c) forming a solar cell comprising the porous insulation substrate and the porous conducting layer.
2. The method according to claim 1 , wherein the yarns of the fabric of woven microfibers comprises a plurality of filaments, and the microfibers in the fiberstock solution are thinner than the filaments in the woven microfiber.
3. The method according to claim 1 , wherein the microfibers in the fiberstock solution have a diameter less than 4 μm, preferably less than 1 μm, and more preferably less than 0.5 μm.
4. The method according to claim 1 , wherein said fabric is made of woven ceramic microfibers, and said fiberstock solution is prepared by mixing liquid and ceramic microfibers.
5. The method according to claim 1 , wherein said fiberstock solution is prepared by mixing liquid and organic microfibers.
6. The method according to claim 1 , wherein said fiberstock solution is prepared by mixing liquid, ceramic microfibers, and organic microfibers.
7. The method according to claim 1 , wherein the thickness of the fabric of woven microfibers is between 4 μm and 30 μm, preferably between 4 μm and 20 μm and more preferably between 4 μm and 10 μm.
8. The method according to claim 1 , wherein the ink is deposited on top of the disposed microfibers to form a porous conducting layer on a first side of a porous insulation substrate, and step a) further comprises covering a second side of the fabric with the fiberstock solution, and draining the liquid from the fiberstock solution through the holes in the fabric, and step b) further comprises: depositing said ink on the second side of the fabric on top of the disposed microfibers, to form a porous conducting layer on a second side of the porous insulation substrate.
9. The method according to claim 1 , wherein step a) further comprises adding a binder to the fiberstock solution.
10. The method according to claim 1 , wherein the method further comprises adding one or more additives selected from a group including a surfactant, a dispersant, a wetting agent, a defoamer, and a rheology changing agent, to the fiberstock solution.