Scientific Results

Graphene below the percolation threshold in TiO2 for dye-sensitized solar cells

Year: 2015

Authors: Dembele KT., Selopal GS., Milan R., Trudeau C., Benetti D., Soudi A., Natile MM., Sberveglieri G., Cloutier S., Concina I., Rosei F., Vomiero A.

Autors Affiliation: INRS EMT, Varennes, PQ J3X 1S2, Canada;‎ Univ Brescia, Dept Informat Engn, SENSOR Lab, I-25133 Brescia, Italy;‎ CNR INO, SENSOR Lab, I-25123 Brescia, Italy;‎ Ecole Technol Super, Dept Genie Elect, Montreal, PQ H3C 1K3, Canada;‎ CNR IENI, I-35131 Padua, Italy;‎ Univ Padua, Dept Chem Sci, I-35131 Padua, Italy

Abstract: We demonstrate a fast and large area-scalable methodology for the fabrication of efficient dye sensitized solar cells (DSSCs) by simple addition of graphene micro-platelets to TiO2 nanoparticulate paste (graphene concentration in the range of 0 to 1.5 wt%). Two dimensional (2D) Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirm the presence of graphene after 500 degrees C annealing for 30 minutes. Graphene addition increases the photocurrent density from 12.4 mA cm(-2) in bare TiO2 to 17.1 mA cm(-2) in an optimized photoanode (0.01 wt% graphene, much lower than those reported in previous studies), boosting the photoconversion efficiency (PCE) from 6.3 up to 8.8%. The investigation of the 2D graphene distribution showed that an optimized concentration is far below the percolation threshold, indicating that the increased PCE does not rely on the formation of an interconnected network, as inferred by prior investigations, but rather, on increased charge injection from TiO2 to the front electrode. These results give insights into the role of graphene in improving the functional properties of DSSCs and identifying a straightforward methodology for the synthesis of new photoanodes.

Journal/Review: JOURNAL OF MATERIALS CHEMISTRY A

Volume: 3 (6)      Pages from: 2580  to: 2588

KeyWords: OPEN-CIRCUIT VOLTAGE; PHOTOVOLTAIC PERFORMANCE; ZNO NANOCRYSTALLITES; RAMAN-SPECTROSCOPY; CHARGE-TRANSPORT; EFFICIENCY; COMPOSITES; SCAFFOLDS; LIGHT; ENHANCEMENT
DOI: 10.1039/c4ta04395b

Citations: 54
data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2021-10-24
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