Solar Cell Enhancement from Supercritical CO₂ Dye Surface Modification of Mesoporous TiO₂ Photoanodes

In recent years, in an effort to reach Net Zero Emissions, there has been growing interest by various academic and industry communities to develop chemicals and industrial processes that are circular, sustainable and green. We report the rapid, simple and effective surface modification of a porous metal oxide with organic dyes using supercritical carbon dioxide (scCO₂). Titanium dioxide (TiO₂) photoanodes were coated in very short times, under mild conditions and the excess dye recovered afterwards for reuse. The process obviates the need for conventional toxic solvents, the generation of unwanted waste streams, and more importantly, we see an unexpected device performance enhancement of 212 and 163 % for TerCOOTMS, 2 a and TerCN/COOTBDMS, 4 dyes, respectively, when compared to the conventional solvent deposition method.