Supercritical carbon dioxide as a solvent for deposition of a tailored dye in dye sensitized solar cells

We report a new technique whereby dyes can be deposited onto metal oxide surfaces using supercritical carbon dioxide (scCO(2)) for use in solar cell applications. This process eliminates the need for hazardous organic solvents and waste solvents generated during the dyeing process. The solubility of a perylene anhydride dye in scCO(2) is enhanced by the incorporation of fluorinated alkyl subsituents and the use of masked carboxylic binding groups. This allows fast deposition of the dye onto the TiO2 photoanode, resulting in efficient photovoltaic performance. The unreacted dye is then easily recovered in a solid form after the deposition process by venting the carbon dioxide.