Optically Transparent Cathode for Dye-Sensitized Solar Cells Based on Graphene Nanoplatelets

Abstract

Commercial graphene nanoplatelets in the form of optically transparent thin films on F-doped SnO(2) (FTO) exhibited high electrocatalytic activity toward I(3)(-)/I(-) redox couple, particularly in electrolyte based on ionic liquid (Z952). The charge-transfer resistance, R(CT), was smaller by a factor of 5-6 in ionic liquid, compared to values in traditional electrolyte based on methoxypropionitrile solution (Z946). Optical spectra and electrochemical impedance confirm that the film's absorbance scales linearly with R(CT)(-1). Electrocatalytic properties of graphene nanoplatelets for the I(3)(-)/I(-) redox reaction are proportional to the concentration of active sites (edge defects and oxidic groups), independent of the electrolyte medium. Dye-sensitized solar cell (DSC) was assembled with this material as a cathode. Semitransparent (>85%) film of graphene nanoplatelets presented no barrier to drain photocurrents at 1 Sun illumination and potentials between 0 and ca. 0.3 V, but an order of magnitude decrease of R(CT) is still needed to improve the behavior of DSC near the open circuit potential and, consequently, the fill factor. We predict that the graphene composite is a strong candidate for replacing both Pt and FTO in cathodes for DSC.

Large-Scale Production of Size-Controlled MoS2 Nanosheets by Shear Exfoliation

“…8,23 Such dispersions can be used to process the nanosheets into functional structures such as films, networks and composites. 20,[24][25][26] Such structures have proven useful in a range of application areas including plasmonics, 27 photodetectors, 24,28,29 electrodes in dye-sensitised solar cells, 30 supercapacitors 31 and batteries 26,32 or electro-catalysts 33 for hydrogen evolution.…”

Graphene-MoS2nanosheet composites as electrodes for dye sensitised solar cells

“…In both cases, it is likely that the catalytically active sites lie on the nanosheet edge. [14,15,17]. This is certainly the case for MoS2 nanosheets when catalysing the hydrogen evolution reaction [41] and Ni(OH)2 nanosheets when catalysing the oxygen evolution reaction.…”

“…The importance of thickness in these studies is often overlooked. While many of these carbon electrodes have been in excess of a micron in thickness, Kavan et al have produced thin catalytic graphene films with high transparencies [17]. However, what is really needed is a comprehensive study on the dependence of DSSC cell performance on graphene counter electrode thickness.…”

“…[38][39][40] The resultant nanosheets have been shown to have virtually no basal plain defects introduced during the exfoliation process. The only defects are due to edge sites which tend to be electrochemically active [17,41]. Using these methods, it is simple to produce mixed dispersions of different types of nanosheets (e.g.…”

Artemisia herba-alba Asso eco-friendly reduced few-layered graphene oxide nanosheets: structural investigations and physical properties

“…Owning to its unique physical and chemical properties, this material is set to revolutionize the twenty-first century for its wide practical uses, such as in nanoelectronics, (5,6), sensors, (7,8), capacitors, (9)(10)(11), solar cells, (12)(13)(14), fuel cells, (15,16), Li ion batteries, (17)(18)(19), photocatalysis, (20,21), electrocatalysis, (22,23), drug delivery (24,25) and plasmonics (26,27). Given this exceptional level of utility, there is a clear need to prioritize processes that are amenable to the large-scale synthesis of highquality graphene, at low cost and with easy processing methods.…”