In:
Science Advances, American Association for the Advancement of Science (AAAS), Vol. 2, No. 6 ( 2016-06-03)
Abstract:
Metal-free carbon-based electrocatalysts for dye-sensitized solar cells (DSSCs) are sufficiently active in Co(II)/Co(III) electrolytes but are not satisfactory in the most commonly used iodide/triiodide (I − /I 3 − ) electrolytes. Thus, developing active and stable metal-free electrocatalysts in both electrolytes is one of the most important issues in DSSC research. We report the synthesis of edge-selenated graphene nanoplatelets (SeGnPs) prepared by a simple mechanochemical reaction between graphite and selenium (Se) powders, and their application to the counter electrode (CE) for DSSCs in both I − /I 3 − and Co(II)/Co(III) electrolytes. The edge-selective doping and the preservation of the pristine graphene basal plane in the SeGnPs were confirmed by various analytical techniques, including atomic-resolution transmission electron microscopy. Tested as the DSSC CE in both Co(bpy) 3 2+/3+ (bpy = 2,2′-bipyridine) and I − /I 3 − electrolytes, the SeGnP-CEs exhibited outstanding electrocatalytic performance with ultimately high stability. The SeGnP-CE–based DSSCs displayed a higher photovoltaic performance than did the Pt-CE–based DSSCs in both SM315 sensitizer with Co(bpy) 3 2+/3+ and N719 sensitizer with I − /I 3 − electrolytes. Furthermore, the I 3 − reduction mechanism, which has not been fully understood in carbon-based CE materials to date, was clarified by an electrochemical kinetics study combined with density functional theory and nonequilibrium Green’s function calculations.
Type of Medium:
Online Resource
ISSN:
2375-2548
DOI:
10.1126/sciadv.1501459
Language:
English
Publisher:
American Association for the Advancement of Science (AAAS)
Publication Date:
2016
detail.hit.zdb_id:
2810933-8
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