Decoupling light absorption and charge transport properties in near IR-sensitized Fe2O3 regenerative cells

We report a regenerative iron oxide nanorod solar cell sensitized with squarine (SQ02) dye, which improves the overall light harvesting due to the dye's complementary absorption. The use of illumination sources which enabled selective excitation of Fe2O3 and the dye independently allowed the decoupling of transport and light absorption in Fe2O3. From absorbed photon-to-current conversion efficiency (APCE) calculations, it was found out that about 80% (at lambda = 680 nm) of the absorbed photons in SQ02 dye are converted to electrons and transported without any further loss into the FTO electrode. Impedance spectroscopy revealed that bulk recombination is still a prominent problem while utilizing hematite as a photoanode in a dye sensitized configuration.