Method for manufacturing dye-sensitized solar cells and solar cells so produced
A dye-sensitized solar cell having a porous conductive powder layer, which layer is formed by deposition of a deposit comprising metal hydride particles onto a substrate; heating the deposit in a subsequent heating step in order to decompose the metal hydride particles to metal particles; and sinter said metal particles for forming a porous conductive powder layer.
1. A method for manufacturing a porous conductive powder stack for a dye-sensitized solar cell, comprising:
providing an electrically insulating flexible porous substrate, the electrically insulating flexible porous substrate having a first surface and a second surface respectively at opposite sides of the electrically insulating flexible porous substrate relative to a direction that traverses the porous conductive powder stack;
printing a first powder deposit comprising titanium hydride particles onto the first surface of the electrically insulating flexible porous substrate to form a porous conductive powder layer back contact;
printing a second powder deposit comprising titanium hydride particles onto the second surface of the electrically insulating flexible porous substrate to form a porous conductive powder layer counter electrode;
heating the first powder deposit and the second powder deposit comprising titanium hydride particles in one or more heat treatment steps to decompose the titanium hydride particles in both the first powder deposit and the second powder deposit comprising titanium hydride particles to titanium particles; and
sintering the titanium particles to form the porous conductive powder stack.
2. The method according to claim 1 , wherein the one or more heat treatment steps comprise a heating step performed at a temperature above the hydride decomposition temperature and below the sintering temperature of the titanium particles, said temperature being in the range of between 350-500° C., and a subsequent heating step performed at a temperature where the titanium particles sinter.
3. The method according to claim 1 , wherein the heating to decompose the titanium hydride particles and the sintering of the titanium particles is performed in one heat treatment step at a temperature where the titanium particles sinter.
4. The method according to claim 1 , wherein the titanium particle sintering temperature is between 550-1250° C.
5. The method according to claim 1 , wherein the sintering of the titanium particles takes place in vacuum or inert gas.
6. The method according to claim 1 , wherein the porous conductive powder stack comprises sintered metal particles having non-spherical, irregular form.
7. The method according to claim 1 , wherein the electrically insulating flexible porous substrate is a porous ceramic substrate.
8. The method according to claim 7 , wherein a surface of the porous ceramic substrate is smoothened before printing at least one of the first powder deposit or the second powder deposit comprising titanium hydride particles.
9. The method according to claim 1 , wherein the porous conductive powder stack has a sheet resistance <1 ohm/sq.
10. The method according to claim 1 , wherein printing of at least one of the first powder deposit or the second powder deposit comprising titanium hydride particles comprises screen printing.
11. The method according to claim 1 , wherein the second powder deposit comprising titanium hydride particles comprises a catalyst for forming the porous conductive powder layer counter electrode.
12. The method of claim 1 , wherein the electrically insulating flexible porous substrate is a ceramic.