Substitution of ethynyl-thiophene chromophores on ruthenium sensitizers: Influence on thermal and photovoltaic performance of dye-sensitized solar cells

Abstract

A new high molar extinction coefficient ruthenium(II) bipyridyl complex, Ru(2,2-bipyridine-4,4′-dicarboxylic acid)(4,4′-bis((3-hexylthiophen- 2-yl)ethynyl)-2,2′-bipyridine)(NCS)2 (N(C4H9)4), MC101 was synthesized and fully characterized by 1H-NMR, ESI-MASS, FT-IR, UV-Vis., and fluorescence spectroscopes. The dye showed relatively high molar extinction coefficient of 25.0×10 3M -1 cm -1 at λ maximum of 544nm, while the reference C101 has shown 15.8×10 3M -1cm -1 at λ maximum 528nm. The monochromatic incident photon-to-collected electron conversion efficiency of 44.1 was obtained for MC101 over the entire visible range, while the C101 sensitized solar cell fabricated and evaluated under identical conditions exhibited 40.1. The DSSCs fabricated with 0.54cm 2 active area TiO2 electrodes and high efficient electrolyte (E01), from the sensitizers MC101 and C101 exhibited energy conversion efficiencies of 3.25 (short-circuit current density (JSC) = 7.32mA/cm 2, VOC = 610mV, ff = 0.725) and 2.94 (JSC = 6.60mA/cm 2; VOC = 630mV; ff = 0.709), respectively, under air mass of 1.5 sunlight. © 2012 Malapaka Chandrasekharam et al.