Patent ID: 8252620

Claim:
A process for impregnating a photosensitizing dye onto a conductive substrate of a photoanode, said photoanode comprising a transparent conductive substrate, a metal oxide layer deposited on a conductive surface of the conductive substrate, and a photosensitizing dye adsorbed on the metal oxide layer, said process comprising the following steps: a) preparing a conductive substrate having a metal oxide layer deposited on a conductive surface thereof; b) impregnating the metal oxide layer of the conductive substrate in a solution of photosensitizing dye in a vessel; c) introducing an inert gas into the vessel to maintain a first pressure therein for a period of time, wherein the solution is expanded by the inert gas; and d) further pressurizing the vessel with the inert gas and maintaining at a second pressure higher than the first pressure for a period of time, wherein the inert gas dissolves more into the solution, creating an anti-solvent effect, so that the photosensitizing dye is further deposited onto the metal oxide layer due to the anti-solvent effect.