Page 409 - Polymer-based Nanocomposites for Energy and Environmental Applications

366 Polymer-based Nanocomposites for Energy and Environmental Applications

Fig. 13.4 Schematic of an industrial sputtering R2R system.
Reproduced with permission from Segawa T, Ikari Y. New roll-to-roll sputtering system for
wide film and application examples. Kobelco Technology; 2016 [cited 2017 February 9].
Available from: http://www.kobelco.co.jp/english/ktr/pdf/ktr_34/044-051.pdf.

the constituent naphthyl rings of PEN, which are clearly larger than the phenyl rings
in PET [28]. The sheet resistance (R sq ) of ITO-PET or ITO-PEN substrates
1
(10 15 Ω sq ) can reach similar levels to that of FTO-glass substrates
1
(R sq ¼7 15 Ω sq ) [26]. High PCE of about 8.1% has been obtained from plastic-
substrate-based DSC [29]. However, the low thermal stability (melting point at
235°C), the moisture and oxygen permeability, and the brittle and unstable nature
of ITO layer, especially under bending forces, are some of the disadvantages of
ITO-PET and PEN films that limit the performance of DSC [14,30]. Despite the
use of different materials, for example, a layer of graphene, silver or carbon nanotube
networks, or conductive polymers, in place of the transparent conductive layer
and more stable and costly film work, they have not yet achieved commercial
success [31–33].

13.2.2.2 Photoelectrodes

PEs in DSCs are conventionally based on wide-bandgap semiconductor, such as
TiO 2 -coated conductive glass or plastics. The main functions of this layer are charge
transfer from excited dye molecules to TCO electrodes and being a scaffold for