Oxygenated multi-walled carbon nanotubes (OMWNTs) were employed as additives in conventional TiO2- based photoanodes and platinum-free conducting polymer-based photocathodes. The OMWNTs were induced to form covalent bonds with TiO2 nanoparticles (NPs) and were successfully intercalated into a poly (3, 4-ethylenedioxythiophene)- polystyrene sulfonate (PEDOT:PSS) network. Furthermore, a dye-sensitized TiO2-OMWNT-based photoanode and a PEDOT:PSS-OMWNT-based electrocatalytic photocathode were both assembled into a photoelectrochemical cell. Replacing the typical platinized photocathode with PEDOT:PSS-OMWNTs enhances the energy conversion efficiency by approximately 13.9% when compared to a typical dye-sensitized solar cell composed of FTO/TiO2/N719//Pt/ FTO. Similarly, a 25.6% increase in efficiency was observed by a spray-coated TiO2-OMWNT layer as the photoanode instead of simple anatase TiO2 NPs. In addition, 42.9% higher efficiency was achieved by utilizing the two OMWNTmodified electrodes together. This excellent performance is attributed to the synergistic effect of the OMWNT-modified photoanode and photocathode. This may be related to the effective suppression of unwanted back transport and recombination reactions.

Dye-sensitized Solar Cell Oxygenated Multi-walled Carbon Nanotubes PEDOT:PSS Platinum-free Counter Electrode TiO2

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