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Reduced Graphene Oxide Wrapped Mesoporous Hierarchical TiO 2 ‐CdS as a Photoanode for High‐Performance Dye‐Sensitized Solar Cells
Author(s) -
Zhang Yanan,
Wang Chengxiang,
Yuan Zhimin,
Zhang Luyuan,
Yin Longwei
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201601535
Subject(s) - graphene , mesoporous material , oxide , dye sensitized solar cell , materials science , nanotechnology , heterojunction , band gap , chemical engineering , dielectric spectroscopy , chemistry , electrochemistry , optoelectronics , electrode , electrolyte , catalysis , biochemistry , engineering , metallurgy
We developed a facile strategy for the fabrication of TiO 2 /CdS/RGO (RGO = reduced graphene oxide) composites as photoanodes for dye‐sensitized solar cells (DSSCs) by growing CdS on the surface of mesoporous hierarchical TiO 2 and then wrapping the TiO 2 /CdS with graphene oxide nanosheets. The TiO 2 /CdS/RGO nanostructures display an enhanced light‐harvesting efficiency with a redshift from the ultraviolet to visible region and show an improved dye‐adsorption capacity owing to the large surface area and mesoporous structures. Furthermore, the recombination of photoinduced electron–hole pairs can be greatly suppressed owing to the matched band‐gap structures of TiO 2 and CdS. The RGO nanosheets have excellent electric conductivity and provide unhindered pathways for accelerated electron transfer. Electrochemical impedance spectroscopy measurements demonstrate the enhanced charge‐transfer kinetics and prolonged lifetime of the photogenerated electrons for the TiO 2 /CdS/RGO nanostructures. DSSCs based on TiO 2 /CdS/RGO photoanodes exhibit a greatly enhanced short‐circuit current density of 13.27 mA cm –2 and an improved photoelectric conversion efficiency of up to 6.5 %, and these values are 31 and 44 % higher than those of DSSCs based on a pristine TiO 2 photoanode. The remarkable photoelectric performance of the DSSCs based on mesoporous hierarchical TiO 2 /CdS/RGO hybrid photoanode can be attributed to synergistic effects between the TiO 2 /CdS heterojunction and the graphene nanosheets.