활동

The selection of solvent for preparing a working electrode (and to act as the electrolyte) is known to influence the

efficiency of dye-sensitized solar cells. In this topical review, results taken from a systematic study are presented from

the authors’ own lab examining how protic and aprotic solvents, as well as solvent polarity, affect adsorption of carboxylic

dyes on the titanium dioxide nanoparticle surface and electron injection from the dye to the semiconductor. Adsorption of dye

molecules on nanoparticle surfaces is measured through second harmonic light scattering and electron injection through

ultrafast transient mid-infrared absorption. It is revealed that protic solvents do not allow direct adsorption of the dye

onto the semiconductor surface, due to hydrogen bonding with the dye and competitive binding to the semiconductor surface.

Aprotic solvents, on the other hand, support solvation of the dye molecules but also facilitate dye adsorption on the

semiconductor nanoparticle. Among aprotic solvents, it is

found that solvents with higher polarity result in larger adsorption free energy for the dye and faster electron injection.

Overall, these studies reveal that aprotic solvents with high solvent polarity (such as acetonitrile) yield more efficient

solar cell devices.