Conducting polymer/in-situ generated platinum nanoparticle nanocomposite electrodes for low-cost dye-sensitized solar cells

Here we report new low-cost nanocomposite counter electrodes for dye-sensitized solar cells (DSSCs), which were prepared by in-situ generation of platinum (Pt) nanoparticles inside poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) solutions at room temperature. The Pt nanoparticles (Ptnp) were evenly dispersed in the PEDOT:PSS films and their size was 20∼40 nm. The PEDOT:PSS-Ptnp films were well coated on substrates, and their optical transmittance was slightly better than conventional thermally-reduced Pt electrode. The short circuit current density of DSSCs with the PEDOT:PSS-Ptnp films was almost comparable to that with the conventional Pt film. The thickness control experiment disclosed that the series resistance of the PEDOT:PSS-Ptnp films is mainly responsible for the low fill factor. We found that the Ptnp was enriched on the surface of the nanocomposite films when the spin-coating speed was high, which has been assigned as an additional reason for the improved device performance. Hence further improvement in device performance is expected by employing high conductivity PEDOT:PSS materials. Finally, we expect that the present method can contribute to the fabrication of low-cost DSSCs using flexible plastic film substrates at low temperatures.