Dye molecular structure device open-circuit voltage correlation in Ru(II) sensitizers with heteroleptic tridentate chelates for dye-sensitized solar cells
Journal
Journal of the American Chemical Society
Journal Volume
134
Journal Issue
17
Pages
7488-7496
Date Issued
2012
Author(s)
Abstract
Dicarboxyterpyridine chelates with π-conjugated pendant groups attached at the 5- or 6-position of the terminal pyridyl unit were synthesized. Together with 2,6-bis(5-pyrazolyl)pyridine, these were used successfully to prepare a series of novel heteroleptic, bis-tridentate Ru(II) sensitizers, denoted as TF-11-14. These dyes show excellent performance in dye-sensitized solar cells (DSCs) under AM1.5G simulated sunlight at a light intensity of 100 mW cm -2 in comparison with a reference device containing [Ru(Htctpy)(NCS) 3][TBA] 3 (N749), where H 3tctpy and TBA are 4,4′,4″-tricarboxy-2,2′:6′,2″- terpyridine and tetra-n-butylammonium cation, respectively. In particular, the sensitizer TF-12 gave a short-circuit photocurrent of 19.0 mA cm -2, an open-circuit voltage (V OC) of 0.71 V, and a fill factor of 0.68, affording an overall conversion efficiency of 9.21%. The increased conjugation conferred to the TF dyes by the addition of the π-conjugated pendant groups increases both their light-harvesting and photovoltaic energy conversion capability in comparison with N749. Detailed recombination processes in these devices were probed by various spectroscopic and dynamics measurements, and a clear correlation between the device V OC and the cell electron lifetime was established. In agreement with several other recent studies, the results demonstrate that high efficiencies can also be achieved with Ru(II) sensitizers that do not contain thiocyanate ancillaries. This bis-tridentate, dual-carboxy anchor configuration thus serves as a prototype for future omnibearing design of highly efficient Ru(II) sensitizers suited for use in DSCs. © 2012 American Chemical Society.
SDGs
Other Subjects
Dye-Sensitized solar cell; Electron lifetime; Excellent performance; Fill factor; Heteroleptic; Light intensity; Light-harvesting; Overall conversion efficiency; Pendant groups; Photovoltaic energy conversion; Pyridyl; Recombination process; Reference devices; Short-circuit photocurrent; Simulated sunlight; Terpyridines; Chelation; Conversion efficiency; Open circuit voltage; Photoelectrochemical cells; Solar cells; Ruthenium alloys; chelate; ruthenium derivative; tf 11; tf 12; tf 13; tf 14; tricarboxyterpyridine ruthenium sensitizer; unclassified drug; article; cell type; chemical structure; conjugation; dye sensitized solar cell; electric potential; energy conversion; light harvesting system; light intensity; simulation; sunlight; synthesis
Type
journal article