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Band‐Edge Engineered Hybrid Structures for Dye‐Sensitized Solar Cells Based on SnO 2 Nanowires
Author(s) -
Gubbala Suresh,
Chakrapani Vidhya,
Kumar Vivekanand,
Sunkara Mahendra K.
Publication year - 2008
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200800099
Subject(s) - nanowire , materials science , open circuit voltage , nanoparticle , optoelectronics , nanotechnology , dye sensitized solar cell , hybrid solar cell , energy conversion efficiency , chemical engineering , voltage , electrode , polymer solar cell , chemistry , physics , quantum mechanics , engineering , electrolyte
In this report, we show for the first time that SnO 2 nanowire based dye sensitized solar cells exhibit an open circuit voltage of 560 mV, which is 200 mV higher than that using SnO 2 nanoparticle based cells. This is attributed to the more negative flat band potential of nanowires compared to the nanoparticles as determined by open circuit photo voltage measurements made at high light intensities. The nanowires were employed in hybrid structures consisting of highly interconnected SnO 2 nanowire matrix coated with TiO 2 nanoparticles, which showed an open circuit voltage of 720 mV and an efficiency of 4.1% compared to 2.1% obtained with pure SnO 2 nanowire matrix. The electron transport time constants for SnO 2 nanowire matrix were an order of magnitude lower and the recombination time constants are about 100 times higher than that of TiO 2 nanoparticles. The higher efficiency observed for DSSCs based on hybrid structure is attributed to the band edge positions of SnO 2 relative to that of TiO 2 and faster electron transport in SnO 2 nanowires.