Photovoltaic Characteristics of Multiwalled Carbon Nanotube Counter-Electrode Materials for Dye-Sensitized Solar Cells Produced by Chemical Treatment and Addition of Dispersant

Abstract

Multiwalled carbon nanotubes (MWCNTs) have excellent electrical conductivity and good chemical stability, and are used as counter electrodes in dye-sensitized solar cells (DSSCs). The counter electrodes collect electrons from the external circuit and catalyze the redox reaction in the electrolyte. Electrocatalysis is an important step for generating energy from triiodide reduction in DSSCs. In this study, chemically treated MWCNTs were investigated for improving the photovoltaic performance of DSSCs. The MWCNTs were modified through chemical oxidation with sulfuric acid/nitric acid (H2SO4/HNO3) or potassium persulfate/sodium hydroxide (K2S2O8/NaOH). Nanocellulose (CNC) was used as a dispersant to improve the photovoltaic performance and dispersibility as an alternative material for counter electrodes in DSSCs. The counter electrodes were prepared on fluorine-doped tin oxide (FTO) glass substrates by spin coating nanofluids. Morphological and structural investigations were performed using scanning transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, and Raman spectroscopy. The electrical conductivity and UV light absorption of the DSSCs were analyzed to evaluate their photovoltaic performance. The results of these analyses showed that chemical functionalization and addition of CNC were effective for increasing the electrical conductivity and UV light absorption. Finally, all result trends were the same. Increasing the dispersibility of the counter electrode was found to improve the reduction of I3− at the interface between the MWCNTs and the electrolyte, thereby, improving the energy conversion efficiency.

Graphene Quantum Dots Embedded in NiCo2S4/MWCNT Nanocomposite as a Promising Candidate for Supercapacitors and I3– Reduction in Dye-Sensitized Solar Cells

“…Since CE regenerates the redox couple, Pt-based electrodes are being extensively used as they have excellent corrosion stability against the iodine electrolyte, thereby delivering higher PCE. , The higher cost of Pt forces the researchers to find alternative materials for CE. Few CE materials with high PCE have already been reported which include transition metal nitrides, , chalcogenides, , inorganic materials, and carbon-based materials. − Among them, the transition metal sulfides have received more attention because of their conductivity, shallow bandgap and band position, strong quantum size effect, and small effective mass, , which are useful in the field of energy conversion and energy storage devices. − For example, Gurulakshmi et al prepared an MoS 2 through the electrodeposition method and employed it as a CE for DSSC, reporting a PCE of 4.84% . Xianqing Liu et al have synthesized VS 2 nanofibers by a in situ hydrothermal method and observed a PCE of 6.24%, which is compared with the Pt CE cell (6.44%) .…”

Counter electrode materials based on carbon nanotubes for dye-sensitized solar cells

“…To further enhance the performance of the CE, a silver (Ag) film was also placed between the FTO glass and the SWCNTs based electrode, thus leading to a drastic increase of the cell efficiency up to 1.3037%. Kim et al [155] also functionalized MWCNTs with an acid as well as a base and used them as CEs in DSSCs employing nanocellulose as dispersant. They observed a higher efficiency for base functionalized MWCNTs in comparison to pristine and acid functionalized.…”

New Trends in Carbon Nanostructured Based Counter Electrode for Dye-Sensitized Solar Cell: A Review

“…Carbon nanotubes also have a large electron storage capacity and show electronic conductivity similar to metals which makes them a reliable candidate to be used in DSSCs. Researchers are focusing their attention on using CNTs as potent photocathode for DSSCs and replacing traditional platinum metal-based cathode 26,27 .…”