Poly(3,4-ethylenedioxythiophene) doped with various carbon-based materials as counter electrodes for dye sensitized solar cells

Various carbon-based materials, poly(3,4-ethylenedioxythiophene) (PEDOT) and titanium dioxide (TiO2) were used to fabricate new counter electrodes namely poly(3,4-ethylenedioxythiophene)-reduced graphene oxide/titanium dioxide (PEDOT-rGO/TiO2), poly(3,4-ethylenedioxythiophene)-nanocrystalline cellulose/titanium dioxide (PEDOT-NCC/TiO2) and poly(3,4-ethylenedioxythiophene)-multiwalled carbon nanotubes/titanium dioxide (PEDOT-MWCNT/TiO2). MWCNT and rGO provided high electrical conductivity and a large surface area, whereas NCC offered a large surface area and high optical transparency which is an important criterion to fabricate a good counter electrode for enhanced dye-sensitized solar cell (DSSC) performance. In addition, carbon-based materials have high availability and low cost compared to platinum-based materials which are more expensive and difficult to source. The PEDOT-NCC/TiO2 counter electrode exhibited good electrocatalytic activity towards triiodide ion reduction and yielded a power conversion efficiency of 2.10%, which was much higher compared to PEDOT-rGO/TiO2 (1.11%) and PEDOT-MWCNT/TiO2 (1.29%). PEDOT-NCC/TiO2 also displayed lower charge transfer resistance (R-ct1 = 10.4 Omega.cm(2)) and higher cathodic peak current density (I-cp = -2.60 mA.cm(-2)) as compared to the other counter electrodes. (C) 2017 Elsevier Ltd. All rights reserved.