Carbon nanomaterial based counter electrodes for dye sensitized solar cells

•We have developed new platinum-free counter electrode (CE) for DSSCs.•We have developed new PEDOT: PSS–graphene and carbon nanotube composites.•Efficiency of up to 4.10% against one of 3.90% for a standard Pt based CE (“open cell” fabrication approach).•Finally, we have developed new Pt- and TCO-free CEs.

In this paper, we report a new cost effective platinum-free counter electrodes (CEs) for dye sensitized solar cells (DSSCs). The CEs were produced using Graphene Nanoplatelets (GNPs) or multi-wall carbon nanotubes (MWCNTs) or various weight % of hybrid GNPs and MWCNTs mixtures. These materials have been dispersed using PEDOT: PSS polymer and then deposited on fluorine doped tin oxide (FTO) glass as well as on a non-conducting glass substrate by a drop casting method. The testing of these electrodes in DSSCs have demonstrated a power conversion efficiency of up to 4.10% to compare with the power conversion efficiency of 3.90% for the DSSC with a standard Pt based CE. New CEs were also made where both Pt and FTO were completely replaced by the hybrid PEDOT: PSS–GNPs–MWCNT nanomaterials. The DSSC with these new platinum- and FTO-free CEs have demonstrated an efficiency of up to 2.48%.