Transparent graphene–platinum nanohybrid films for counter electrodes in high efficiency dye-sensitized solar cells

Abstract

A dispersion of platinum-on-graphene was prepared essentially by a two-step process, involving uniform distribution of graphene nanoplatelets in a cosolvent of ethanol-water in the presence of a polymeric dispersant and subsequent in situ reduction of dihydrogen hexachloroplatinate to metallic platinum on the graphene surface. The process generated platinum nanoparticles (PtNPs) of ca. 4.0-10 nm in diameter on the graphene surface. The platinum-on-graphene dispersion was coated on an FTO glass to prepare a counter electrode (CE) for a dye-sensitized solar cell (DSSC). The hybrid film of platinum nanoparticles and graphene nanoplatelets (PtNP/GN) showed a transparency of 70% at 550 nm, indicating its suitability as a CE material for a rear-illuminated DSSC. The DSSC with the CE having the film of PtNP/GN exhibited a power conversion efficiency (h) of 8.00%, superior to 7.14% of the DSSC with a conventional sputtered platinum (s-Pt) CE. In the case of rear-illumination the DSSC showed an h of 7.01%, while the DSSC with the conventional s-Pt showed an h of only 2.36%. HRTEM and FE-SEM were used to observe the dispersion of the hybrid material in the solvent, UV-vis spectroscopy and cyclic voltammetry were used to characterize the films, and IPCE spectra and electrochemical impedance spectra were used to explain the photovoltaic parameters of the DSSCs.

Ternary composites of Ni–polyaniline–graphene as counter electrodes for dye-sensitized solar cells

“…Some platinum-free counter electrode materials like graphite, carbon black, carbon nanotubes and conducting polymers have been investigated over the past few years. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Polyaniline (PANI) is well known as an important electronic conducting polymer due to its many desirable qualities such as low cost, environmental stability, and high degree of processability. PANI has been employed as the counter electrode for DSSCs, and has exhibited electrocatalytic activity for the reduction of triiodide ions.…”

Functionalized graphene and other two-dimensional materials for photovoltaic devices: device design and processing

“…359,360 Meanwhile, they prepared edge-carboxylated graphene nanoplatelets (ECGNPs) by the simple and eco-friendly ball-milling of graphite. 363 Being similar to OPVs, graphene has been successfully used in flexible DSSCs. For example, Dao et al synthesized Pt NPs (1-2.5 nm) on CVD grown graphene by a using dry plasma reduction method near room temperature under atmospheric pressure, which had a transmittance of B80%.…”

The Role of Sulfur-Related Species in Oxygen Reduction Reactions

“…Currently, S-related species represent promising active sites for ORR catalysis. S doping can lead to a higher degree of graphitization because S can react with imperfect carbon to form CS 2 gas [52]. Furthermore, S-doping can modify the spin density distributions around the carbon framework.…”