Molecular-Level Insulation: An Approach to Controlling Interfacial Charge Transfer

In this presentation, we report a novel approach to the attachment of molecular dyes to nanocrystalline TiO$_{2 }$electrodes. New azo dye rotaxane was synthesized by encapsulating an organic dye inside cyclodextrin, and it is shown to exhibit strong binding to the metal oxide electrode. The encapsulation results in a well-defined spatial separation of the organic dye from the electrode surface, allowing the photogeneration of a long-lived charge separated state. Herein we demonstrate that such cyclodextrin threaded sensitizer dye rotaxanes can be used to functionalise nanocrystalline TiO$_{2}$, resulting in a long-lived photogenerated charge separation.