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

13 Oct 2011

A new technique has been developed to deposit dyes onto metal oxide surfaces using supercritical carbon dioxide (scCO₂), resulting in efficient photovoltaic performance.

Dye sensitized solar cells (DSSCs) have become a very promising option as a cheap, non-silicon based devise to harness solar energy. At present a range of organic solvents are used to deposit the dye component onto the metal oxide surface. However, the approach is still very empirical and may not be ideal for industrial processes as manufacturing parameters, such as scale, flammability, waste disposal, dye recovery and cost, need to be considered.

In this work scientist from the UK and Australia led by Gavin Collis have employed scCO₂ as the solvent for dye deposition. As well as eliminating the need for hazardous organic solvents and waste solvents generated during the process, it also allows the unreacted dye to be recovered easily in solid form after venting the carbon dioxide. This technique now allows dye deposition to be completed in 2 hours, a dramatic decrease from the 15 hours it took using organic solvents.