Optically Transparent FTO-Free Cathode for Dye-Sensitized Solar Cells

Abstract

The woven fabric containing electrochemically platinized tungsten wire is an affordable flexible cathode for liquid-junction dye-sensitized solar cells with the I3(-)/I(-) redox mediator and electrolyte solution consisting of ionic liquids and propionitrile. The fabric-based electrode outperforms the thermally platinized FTO in serial ohmic resistance and charge-transfer resistance for triiodide reduction, and it offers comparable or better optical transparency in the visible and particularly in the near-IR spectral region. The electrode exhibits good stability during electrochemical loading and storage at open circuit. The dye-sensitized solar cells with a C101-sensitized titania photoanode and either Pt-W/PEN or Pt-FTO cathodes show a comparable performance.

Low-temperature Fabrication of Highly-Efficient, Optically-Transparent (FTO-free) Graphene Cathode for Co-Mediated Dye-Sensitized Solar Cells with Acetonitrile-free Electrolyte Solution

“…3) for all the electrolyte solutions tested. In accord with earlier reports [8,[16][17][18][19]32] there is reasonable matching of the D values from CV and EIS.…”

“…cheaper price, better conductivity and better optical transmittance [8]. The structure of our Sefar-B23 fabric is shown on Figure S9 (Supporting info).…”

“…(The coating of PEN causes unwanted darkening of the fabric, too, but it is unavoidable in the dip-coating deposition). Another concern associated with a grid electrode is the complicated mass-transport geometry [8]. Table 1.…”

“…Its replacement by cheaper materials should not cause enhancement of the electrode's electrical resistance (typically 10 Ω/sq for FTO) and optical absorption of visible light (typically 20 % near the peak of solar spectrum).Metallic meshes or metal-wire/polymer-fiber fabric are attractive alternatives for counterelectrodes, offering, moreover, the flexibility as an added practical benefit. An example is platinized-tungsten/PEN fabric (PEN = poly(ethylene 2,6-naphthalate), which was applied in the 8.5%-efficient I-mediated DSC [8]. Further cost reduction is envisaged upon using cheaper (Ptfree) cathode catalyst and common metals, like stainless steel for the counterelectrode.…”

Vegetable-based dye-sensitized solar cells

“…159 Moreover, Pt tends to degrade over time when in contact with the I 3 À /I À liquid electrolyte, reducing the Z of DSSCs. In this context, several groups have used carbon-based nanomaterials as catalysts in the CE, such as amorphous carbon, 161 CNTs, 158,162 hard carbon spherules, 163 graphite, 163 GNPs, 164 nitrogen-doped GNPs, 165 graphene oxide (GO) [166][167][168] and hybrid structures of GNPs-RGO-CNTs 169,170 with results, i.e., Z, close to or exceeding the ones based on Pt. In this context, several groups have used carbon-based nanomaterials as catalysts in the CE, such as amorphous carbon, 161 CNTs, 158,162 hard carbon spherules, 163 graphite, 163 GNPs, 164 nitrogen-doped GNPs, 165 graphene oxide (GO) [166][167][168] and hybrid structures of GNPs-RGO-CNTs 169,170 with results, i.e., Z, close to or exceeding the ones based on Pt.…”