Altering the self-organization of dyes on titania with dyeing solvents to tune the charge-transfer dynamics of sensitized solar cells

Herein we selected the model organic donor-acceptor dye C218 and modulated the self-organization of dye molecules on the surface of titania by changing the dyeing solvent from chlorobenzene to a mixture of acetonitrile and tert-butanol. We further unveiled the relationship between the microstructure of a dye layer and the multichannel charge-transfer dynamics that underlie the photovoltaic performance of dye-sensitized solar cells. Microstructure variations in self-organized dye layers on titania are achieved by choosing different dyeing solvents. The changes are correlated with multichannel charge-transfer dynamics on a broad timescale. Proper dye aggregation for dye-sensitized solar cells can restrain interfacial charge-recombination reactions but does not significantly reduce the carrier photogeneration.