Free‐Standing Graphene/Conducting Polymer Hybrid Cathodes as FTO and Pt‐Free Electrode for Quasi‐State Dye Sensitized Solar Cells

Abstract

Highly conducting freestanding graphene (FSG) was synthesized by the simple vacuum filtration method and utilized as a cathode current collector for (fluorine doped tin oxide) FTO free quasi‐dye sensitized solar cell (q‐DSSC). Subsequently,conducting polymers (CPs) viz., polyaniline (PANI) and poly(3,4‐ethylene‐di‐oxythiophene) (PEDOT) was decorated on FSG surface by electrochemical polymerization which acts as a electrocatalytst for Pt free q‐DSSC. Entirely, the FSG/CPs affords as a novel cathode architecture for FTO/Pt free electrode for q‐DSSCs. Remarkably, the FSG paper electrode exhibits lower sheet resistance (9‐11 Ω sq‐1) than the FTO which was directly utilized as current collector. Interestingly, the FSG/CPs based cathode shows an improved electro‐catalytic behaviour towards tri‐iodide reduction and in particularly, the photovoltaic performance of FSG/PEDOT shows power conversion efficiency (PCE) of 5.4 % compared with Pt/FTO of 5.1 %. It can be stated that synergetic effect of FSG/PEDOT proves to be a cost effective and efficientsubstitute for cathodes in q‐DSSC.

Solar‐Driven Co‐Production of Hydrogen and Value‐Add Conductive Polyaniline Polymer

“…Cyclic voltammograms were performed and results are shown in Figure S6a (Supporting Information). In the first cycle, as the applied bias was increased from 0 to 1.6 V, current rapidly increased at 1.04 V and reached its peak at 1.36 V. This indicates that for initiating the ANI polymerization, a bias of 1.04 V is required, consistent with values (≈1.05 V) reported in the literature, [30,32,37] well below the theoretical limit of 1.23 V for water splitting. In the subsequent cycles, the initiation potential for the polymerization process was left-shifted.…”

“…In addition, the curves were accompanied by three anodic peaks of PANI. [32] This suggests that the polymerization process became progressively easier (i.e., left shift implies lower potentials required) in the subsequent cycles after the formation of cation radicals in the first cycle [32,[38][39][40] and after the growth of PANI on FTO. Further investigation into the process dynamics was conducted and will be presented below.…”

“…All of these pose challenge to determine the Gibbs free energy or the theoretical minimum potential for the ANI polymerization initiation reaction. For a rudimentary determination of solar-to-hydrogen conversion efficiency (η STH ), 1.05 V [30][31][32]37] was assumed for initiating ANI polymerization reaction. This gives a theoretical maximum (see calculation method in the Experimental Section) of 15.5% for the process driven by the external 2-half-cell-in-series silicon PV device or 14.4% for the process driven by the integrated perovskite-solar cell-based photoanode.…”

“…In addition, protons are released during the aniline (ANI) polymerization reaction compensating for hydrogen evolution reaction (HER) usage [ 27 ] and therefore removing the need for acid replenishment during the reaction. While the production of PANI via electrochemical process [ 30–32 ] with the co‐production of H 2 has been reported before. [ 33 ] We have demonstrated here the advantage of utilizing solar power and in particular one single‐junction solar cell for such process taking advantage of lower practical bias of 1.05 V to initiate ANI polymerization, much lower than the theoretical limit (>1.23 V) for traditional water splitting.…”

Benchmarking the Performance of Electropolymerized Poly(3,4‐ethylenedioxythiophene) Electrodes for Neural Interfacing

“…Adapted from ref. [ 45 ] Copyright 2016, Wiley. b) Schematic showing the three‐electrode setup for the galvanostatic electropolymerization.…”