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摘要
A new high molar extinction coefficient ruthenium(II) bipyridyl complex ※cis-Ru(4, -bis(9,9-dibutyl-7-(3,6-di-tert-butyl-9H-carbazol-9-yl)-9H-fluoren-2-yl)-2, -bipyridine)(2, -bipyridine-4, -dicarboxylic acid)(NCS)2, BPFC§ has been synthesized and characterized by FT-IR, -NMR, and ESI-MASS spectroscopes. The sensitizer showed molar extinction coefficient of ˋMˋ1cmˋ1, larger as compared to the reference N719, which showed ˋMˋ1cmˋ1. The test cells fabricated using BPFC sensitizer employing high performance volatile electrolyte, (E01) containing 0.05ˋM I2, 0.1ˋM LiI, 0.6ˋM 1,2-dimethyl-3-n-propylimidazolium iodide, 0.5ˋM 4-tert-butylpyridine in acetonitrile solvent, exhibited solar-to-electric energy conversion efficiency (灰) of 4.65% (short-circuit current density ( ) = 11.52ˋmA/cm2, open-circuit voltage ( ) = 566ˋmV, fill factor = 0.72) under Air Mass 1.5 sunlight, lower as compared to the reference N719 sensitized solar cell, fabricated under similar conditions, which exhibited 灰-value of 6.5% ( = 14.3ˋmA/cm2, = 640ˋmV, fill factor = 0.71). UV-Vis measurements conducted on TiO2 films showed decreased film absorption ratios for BPFC as compared to those of reference N719. Staining TiO2 electrodes immediately after sonication of dye solutions enhanced film absorption ratios of BPFC relative to those of N719. Time-dependent density functional theory (TD-DFT) calculations show higher oscillation strengths for 4, -bis(9,9-dibutyl-7-(3,6-di-tert-butyl-9H-carbazol-9-yl)-9H-fluoren-2-yl)-2, -bipyridine relative to 2, -bipyridine-4, -dicarboxylic acid and increased spectral response for the corresponding BPFC complex. 1. Introduction Dye sensitized solar cells (DSSCs) attracted intense attention among scientific as well as industrial organizations because of their high photon-to-electricity conversion efficiency and low cost compared to traditional photoelectrochemical cells [1每5]. Since Graetzel introduced the first highly efficient nanocrystalline TiO2 sensitized solar cell based on ruthenium(II) bipyridyl complex, N3 as sensitizer, there have been several modifications to improve the overall performance of the test cell devices [6每22]. Among all the components employed in DSSC, sensitizer plays a key role in photovoltaic performance in respect of efficiency and long-term durability. The important tunable properties of sensitizers for high efficient DSSCs are broad absorption (400 to 900ˋnm) and high molar extinction coefficient (thin films and solid state DSSCs), thermal and photochemical stability (long durable), compatibility with TiO2 semiconductor
