Energy efficient, one-step microwave-solvothermal synthesis of a highly electro-catalytic thiospinel NiCo2S4/graphene nanohybrid as a novel sustainable counter electrode material for Pt-free dye-sensitized solar cells

A sustainable rapid microwave-solvothermal (MW-ST) synthesis approach has been successfully demonstrated to develop thiospinel NiCo2S4 nanocrystals and their nanohybrids with graphene nanosheets (GNS) using transition metal-ions (Co2+, Ni2+) and thiourea as a sulfur precursor in the presence of grap...

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Bibliographic Details
Published in:Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2017, Vol.5 (12), p.3146-3155
Main Authors: Krishnapriya, R, Praneetha, S, Rabel, Arul Maximus, Vadivel Murugan, A
Format: Article
Language:English
Subjects:
Graphene
Nanocrystals
Nanostructure
Photovoltaic cells
Platinum
Solar cells
Sustainability
Synthesis
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Summary:A sustainable rapid microwave-solvothermal (MW-ST) synthesis approach has been successfully demonstrated to develop thiospinel NiCo2S4 nanocrystals and their nanohybrids with graphene nanosheets (GNS) using transition metal-ions (Co2+, Ni2+) and thiourea as a sulfur precursor in the presence of graphite oxide (GO). The MW-ST method enables the nucleation and growth of cubic linnaeite-type thiospinel NiCo2S4 nanocrystals and simultaneous in situ ultra-fast polyol-reduction of GO to GNS and its hybridization within 15 min at 200 degree C using ethylene glycol (EG) as the solvent. This process absolutely evades the use of toxic reducing agents or post solid-state sintering at elevated temperatures and subsequent sulphurization using toxic H2S/Na2S gases. The nanocrystallite aggregates (NCS-1)/GNS nanohybrid exhibited a remarkable electro-catalytic activity towards triiodide (I-/I3-) reduction owing to improved electronic conductivity and synergistic effects at NCS-1 and GNS interfaces. The developed NCS-1/GNS nanohybrid as a novel counter electrode (CE) for Pt-free dye sensitized solar cells (DSSCs) demonstrated a high power conversion efficiency (PCE) of 7.98% in comparison to the conventional Pt CE of 8.01% under the same conditions. Hence, this work presents a scalable synthesis of an earth-abundant, thiospinel NiCo2S4/GNS nanohybrid CE via a facile single-step MW-ST process as a potential alternative to expensive Pt as a CE in DSSCs and other electrochemical clean energy systems.
ISSN:2050-7526
2050-7534
DOI:10.1039/c6tc04619c