Carbon nanotube/graphene nanocomposite as efficient counter electrodes in dye-sensitized solar cells

Abstract

We demonstrated the replacement of the Pt catalyst normally used in the counter electrode of a dye-sensitized solar cell (DSSC) by a nanocomposite of dry spun carbon multi-walled nanotube (MWNT) sheets with graphene flakes (Gr-F). The effectiveness of this counter electrode on the reduction of the triiodide in the iodide/triiodide redox (I − /I − 3 ) redox reaction was studied in parallel with the use of the dry spun carbon MWNT sheets alone and graphene flakes used independent of each other. This nanocomposite deposited onto fluorinated tin-oxide-coated glass showed improved catalytic behavior and power conversion efficiency (7.55%) beyond the use of the MWNTs alone (6.62%) or graphene alone (4.65%) for the triiodide reduction reaction in DSSC. We also compare the use of the carbon MWNT/Gr-F composite counter electrode with a DSSC using the standard Pt counter electrode (8.8%). The details of increased performance of graphene/MWNT composite electrodes as studied are discussed in terms of increased catalytic activity permitted by sharp atomic edges that arise from the structure of graphene flakes or the defect sites in the carbon MWNT and increased electrical conductivity between the carbon MWNT bundles by the graphene flakes.

Role of Graphene in Photocatalytic Solar Fuel Generation

“…Similar observations were also reported for CNTs grown on graphene utilized for optoelectronic applications [44][45][46].…”

Facile fabrication of novel silver-polypyrrole-multiwall carbon nanotubes nanocomposite for replacement of platinum in dye-sensitized solar cell

“…[13][14][15] In recent decades various carbon nanomaterials such as amorphous carbon, carbon nanotubes carbon black, and Graphene/carbon nanotubes composites have been employed as a promising alternative to Pt CE owing to their affordable cost, large electrical conductivity, corrosion resistance, and excellent catalytic activity. [16][17][18][19][20][21][22][23][24] Among them, carbon nanotubes have been widely reported as an efficient alternative platinum CE owing to their extraordinary attractive features, notably high conductivity, fast electron transport and high surface area, but their electro catalytic activity for I 3 − reduction are poor. [25][26][27][28] Therefore power conversion efficiency of DSSCs with carbon CEs are still insufficient and should be improved for large scale applications.…”

High-efficiency dye-sensitized solar cells based on nitrogen and graphene oxide co-incorporated TiO2 nanofibers photoelectrode

“…Among the reported exploited doping elements, N atom and carbonaceous materials received particular attention to improve the performance in DSSCs [13,[17][18][19][20]. However, the corresponding concentration of the doping elements should be carefully adjusted as using large amount of these doping species can create carrier recombination centers or light-harvesting competition with dye which greatly minimizes the performances of photoelectrode [21][22][23][24]. Recently, experimental studies have demonstrated that low concentration co-doping of TiO 2 with both non metal-anions and metal-cations can enhance the efficiency of DSSCs compared with mono-doping [25][26][27][28].…”