Electrocatalyst For Dye-sensitized Solar Cells Research Articles

Novel PtO decorated MWCNTs as a highly efficient counter electrode for dye-sensitized solar cells

PtO–MWCNTs nanocomposites were prepared and applied as the counter electrode in dye-sensitized solar cells (DSCs) for the first time. Excellent energy conversion efficiency indicated that the nanocomposite was a promising electrocatalyst for DSCs.

Graphene Nanoplatelets Doped with N at its Edges as Metal‐Free Cathodes for Organic Dye‐Sensitized Solar Cells

Challenging precious Pt-based electrocatalysts for dye-sensitized solar cells (DSSCs), graphene nanoplatelets that are N-doped at the edges (NGnPs) are prepared via simply ball-milling graphite in the presence of nitrogen gas. DSSCs based on specific nanoplatelets designated "NGnP5" display superior photovoltaic performance (power conversion efficiency, 10.27%) compared to that of conventional Pt-based devices (9.96%). More importantly, the NGnP counter electrode exhibits outstanding electrochemical stability and electrocatalytic activity with a cobalt-complex redox couple.

Single-crystal CoSe2 nanorods as an efficient electrocatalyst for dye-sensitized solar cells

Single-crystal CoSe2 nanorods have been used as the electrocatalyst for highly efficient dye-sensitized solar cells.

Zinc Molybdate-carbon Composites as Counter Electrode Materials for Dye-sensitized Solar Cells

Sheet-like structured zinc molybdate (ZnMoO4) was firstly synthesized by hydrothermal method. Then, graphite (G) and conductive carbon (Cc) modified ZnMoO4 (denoted as ZnMoO4-G and ZnMoO4-Cc) were fabricated by dispersing ZnMoO4 into graphite (G) and conductive carbon (Cc) solutions, respectively. The obtained ZnMoO4-G and ZnMoO4-Cc composites were used as electrocatalysts for dye-sensitized solar cells (DSCs), exhibiting promising potential as counter electrode materials. The experimental results demonstrated that the DSC assembled with sole ZnMoO4 showed an overall light conversion efficiency of 4.19%, while the DSCs made of ZnMoO4-G and ZnMoO4-Cc counter electrodes displayed power conversion efficiencies of 6.56% and 7.36%, respectively. The solar cell performance obtained by ZnMoO4-Cc counter electrode was comparable to Pt-based DSCs (7.81%). Various characterization techniques, such as electrochemical impedance spectra (EIS), cyclic voltammetry (CV) and Tafel polarization curve, were employed to evaluate the electrocatalytic activity of all investigated materials. Among all investigated counter electrodes, the high solar cell performance obtained by ZnMoO4-Cc counter electrode could be attributed to superior electrical conductivity of conductive carbon material and excellent 1134 无 机 材 料 学 报 第 29 卷 electrocatalytic activity of sheet-like structured ZnMoO4-Cc.

Ruthenium core-activated platinum monolayer shell high redox activity cathodic electrocatalysts for dye-sensitized solar cells

Here, we have combined the understanding of density functional theory in relation with lattice strain-to-activity correlation to design a Rucore–Ptshell structured electrocatalyst in a dye-sensitized solar cell (DSC) cathode. This electrocatalyst possesses a compressive lattice strain in the shell region which translocates the Pt valence charge to neighboring atoms to decrease the Pt valence band density of states and thus lower the Pt d-band levels. Consequently, compared with DSCs using Pt nanoparticles (NPs) cathode, the Rucore–Ptshell NPs improves the triiodide to iodide redox reduction activity by 2.11-fold and thus boosts the photovoltaic efficiency of DSCs by ∼30.4%. These results provide mechanistic information for the development of DSCs with reduced Pt utilization and programmable electrochemical performance.

Nitrogen-doped graphene for dye-sensitized solar cells and the role of nitrogen states in triiodide reduction

Nitrogen-doped graphene was demonstrated as an efficient and alternative metal-free electrocatalyst for dye-sensitized solar cells. Electrochemical measurements showed that the nitrogen-doping process can remarkably improve the catalytic activity of graphene toward triiodide reduction, lower the charge transfer resistance, and thus enhance the corresponding photovoltaic performance. Furthermore, the nitrogen doping levels ranging from 3.5 at% to 18 at%, as well as the nitrogen states (including pyrrolic, pyridinic and quaternary configurations) in graphene, were controlled to interpret the roles of graphene structure in catalytic activity and device performance. The results suggested that the nitrogen states, rather than the total N content, have a significant effect on the catalytic activity. Both pyridinic and quaternary nitrogen states can provide active sites for promoting triiodide reduction reaction, probably due to the shift in redox potential and the lowered adsorption energy.

Self-assembly of Ni2P nanowires as high-efficiency electrocatalyst for dye-sensitized solar cells

Abstract

Platinum nanoparticles deposited on substrates by solventless chemical reduction of a platinum precursor with ethylene glycol vapor and its application as highly effective electrocatalyst in dye-sensitized solar cells

To deposit nanostructured platinum (Pt) on substrates has fundamental and practical significance as Pt is a noble metal and an effective electrocatalyst. In this paper, we report a facile and scalable method to deposit Pt nanoparticles on substrates through the solventless chemical reduction of H2PtCl6 with vapor of ethylene glycol (EG) below 200°C. The Pt nanoparticles have a size below 6nm, and they homogeneously distribute on the substrates. They have good adhesion to the substrates. They are highly catalytic for the reduction of triiodide that is the chemical reduction at the counter electrode of dye-sensitized solar cells (DSCs). Though DSCs with Pt deposited by the EG vapor reduction and pyrolysis exhibit comparable high photovoltaic efficiency of more than 8% at high Pt loading, the photovoltaic efficiency of DSCs with Pt by the EG vapor reduction is much higher than that by pyrolysis when the Pt loading is quite low. DSCs with a Pt loading of 0.19μgcm−2 deposited by this method can have a power conversion efficiency of 6.61%, which is even higher than that (6.19%) of DSCs with a Pt loading of 0.78μgcm−2 deposited by pyrolysis. Thus, this method can significantly reduce the Pt loading to ¼ or even lower in comparison with Pt by pyrolysis which has been regarded as the method to deposit Pt with the highest electrocatalytic activity as the counter electrode of DSCs. The excellent electrocatalytic activity of Pt is attributed to the small Pt particle size.

Preparation and characterization of low platinum loaded Pt:SnO 2 electrocatalytic films for screen printed dye solar cell counter electrode

A series of low platinum loaded Pt:SnO 2 electrocatalysts for dye-sensitized solar cells were prepared by the hydrogen reduction method at 120 °C. As prepared and annealed at 630 °C samples containing 1.2%, 2% and 3% platinum loaded antimony doped tin dioxide catalytic powders were characterized. The structure and particle sizes are studied by means of high resolution transmission electron microscopy and X-ray diffraction measurement. The metallic state of platinum nanoparticles was observed by X-ray photoelectron spectroscopy. For the paste preparation, differently loaded Pt:SnO 2 powders were each mixed with the ethylcellulose/terpineol printing media. In order to produce symmetrical Pt/Electrolyte/Pt cells for the electrochemical study the pastes were applied onto transparent conductive oxide coated glass by screen printing technology. The charge transfer resistance of these electrodes to the iodide/triiodide redox system in different electrolytes after the thermal sealing of the cells at 630 °C was investigated by electrochemical impedance spectroscopy, which showed that catalytic performance can be improved by homogenous deposition of catalyst on substrate. The surface morphology of the printed catalytic stripes was imaged by field emission scanning electron microscopy and atomic force microscopy.