A Low-Cost Polytetrafluoroethylene-Framed TiO2Electrode Decorated with Oleic Acid-Capped CdSe Quantum Dots for Solar Cell

Abstract

Colloidal CdSe QDs have been assembled, as quantum dot-sensitized solar cells (QDSSCs), on a novel architecture comprising a polytetrafluoroethylene- (PTFE-) framed TiO2electrode for the first time. CdSe QDs are anchored on the surface of the film using a linker molecule (3-mercaptopropionic acid, MPA). The resulting photoelectrode comprises a TiO2compact layer and a PTFE-framed structural layer with average respective thicknesses of 2 μm for the compact layer and either 23 μm or 28 μm for the PTFE-framed structural layer. UV-vis absorption spectra show that more CdSe quantum dots are anchored on the surface of the modified with MPA TiO2film compared to direct absorption onto an unmodified film. Energy conversion efficiencies of up to 0.18% can be achieved with cells prepared from a TiO2(25 μm)/MPA/CdSe QD electrode. Electrochemical impedance measurements show that the recombination resistance is relatively higher for a cell assembled with TiO2(25 μm)/MPA/CdSe QD photoanode than with TiO2(25 μm)/CdSe QD resulting in an increase of cell efficiency. The PTFE-framed structure along with the compact layer is a new approach to QDSSC application that provides a tunable film thickness and a cost-effective preparation technique for the large-scale production of the photoanode.