Page 420 - Polymer-based Nanocomposites for Energy and Environmental Applications

Polymer nanocomposites for dye-sensitized solar cells 377

Fig. 13.11 (A) Real image of bended carbon gel catalyst coated on ITO-PEN and (B) J-V graph
of the DSCs with carbon gel and thermally platinized CEs.
Reproduced with permission from Miettunen K, Toivola M, Hashmi G, Salpakari J, Asghar I,
Lund P. A carbon gel catalyst layer for the roll-to-roll production of dye solar cells. Carbon
2011;49:528–32.

the usage of gelatinized and compressed carbon-based electrode as flexible and
highly conductive CE. They prepared the carbon gel paste using carbon black as
catalyst, graphite as conductive agent, Sb-doped SnO 2 as inorganic binder,
3-methoxypropionitrile (3-MePRN) as solvent, and poly(vinylidene fluoride-co-
hexafluoropropylene) (PVdFHFP) as gelling agent. After coating the carbon gel onto
ITO-PEN substrate by doctor blade and followed heat treatment (110°C for 5 min),
2
they pressed the layer under pressure of 1000 kg cm . The resulted 7–10 μm thick
film was stable, and no visible cracks or flakes appeared even when the sample
was bent to a bending radius of 3 mm (Fig. 13.11). J-V results showed that the DSCs
constructed of carbon-gel-coated ITO-PEN-based CE and platinized FTO-glass-based
CE have nearly the same J sc and V oc . The small difference in PCEs (PCE C-gel 4.24%
and PCE Pt-FTO 4.81%) was attributed to the lower catalytic activity and slightly higher
charge-transfer resistance of the carbon-gel-based CE.

Conductive polymers based CEs
Apart from Pt- and carbon-based materials, conductive polymers like polyaniline
(PANI) [66–68], polypyrrole (PPy) [69–71], and poly(3,4-ethylenedioxythiophene)
(PEDOT) have been used as an efficient and alternative CEs for DSCs. The use of
polymer-based materials offers advantages, such as low cost, high workability grade,
and thermal and chemical stability. The performances of the polymer-based CEs are
highly affected by the type of polymerization method, morphology, and composition
of synthesized polymer [48].