Dispersion Controlled Platinum/Multi-Walled Carbon Nanotube Hybrid for Counter Electrodes of Dye-Sensitized Solar Cells

Platinum (Pt) nanoparticles are incorporated in dispersion controlled multi-walled carbon nanotubes (CNTs) for counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The dispersion of CNTs is controlled by a styrenic block copolymer as a surface modifier, facilitating the fabrication of the CE on F-doped SnO glass (FTO glass) by a screen printing method. By employing sufficiently large amounts of CNTs in a paste and using a stepwise thermal treatment procedure in which organic compounds are successfully removed from the paste while minimising damage to the CNTs, a conductive and uniform CNT coating can be screen-printed onto FTO glass. Pt precursors in the pastes transform to discrete Pt nanoparticles under the thermal treatment conditions, thereby successfully producing a Pt/CNT composite. Incorporation of the small amount of Pt nanoparticles into the CNTs results in significant improvements in the performances of the DSSCs. The DSSC with the Pt/CNT CE also exhibits very stable solar-to-electricity energy conversion efficiency (eta) values for extended light soaking times that are superior to those of DSSC with the standard Pt CE. The results demonstrate the successful combination of DSSC processability, performance and stability enabled by employing Pt/CNT hybrid CEs.