Carbon nanoparticles for counter electrode catalyst in dye-sensitized solar cells

We report dye-sensitized solar cells using low cost carbon nanoparticles as an alternative to platinum as a counter-electrode catalyst for triiodide reduction. The counter carbon-electrode was deposited onto fluorine-doped tin oxide (FTO) by spin coating from an aqueous colloidal suspension of the blend of carbon nanoparticles and TiO₂ nanocrystals. DSSC devices were fabricated using a stable Ru complex dye (Z-907) as the sensitizer. The cells based on carbon-nanoparticle counter electrode were made and then compared with those cells from platinum counter electrode at similar fabrication conditions. The results have shown that the device performance in terms of short circuit current density (Jsc), open circuit voltage (Voc) and energy conversion efficiency (η) from the cells based on carbon nanoparticle counter electrode were comparable to those from platinum counter-electrode devices. The carbon nanoparticle based cells have achieved an overall energy conversion efficiency of 5.55% under one sun AM 1.5 illumination (100 mW/cm²). The carbon nanoparticles showed significant potential as a low cost alternative to the current widely-used platinum.