High molar extinction coefficient Ru(II)-mixed ligand polypyridyl complexes for dye sensitized solar cell application

Abstract

Two new ruthenium(II) mixed ligand terpyridine complexes, Ru(Htcterpy)(NCS)(L1) (N(C4H9)4), mLBD1 and Ru(Htcterpy)(NCS)(L2)(N(C4H9)4), mLBD2 were synthesized and fully characterized by UV-Vis, emission, cyclic voltammogram, and other spectroscopic means, and the structures of the compounds are confirmed by 1H-NMR, ESI-MASS, and FT-IR spectroscopes. The influence of the substitution of L1 and L2 on solar-to-electrical energy conversion efficiency (η) of dye-sensitized solar cells (DSSCs) was evaluated relative to reference black dye. The dyes showed molar extinction coefficients of 17600M-1cm-1 for mLBD1 and 21300M -1cm-1 for mLBD2 both at maximum of 512nm, while black dye has shown 8660M-1cm-1 at maximum of 615nm. The monochromatic incident photon-to-collected electron conversion efficiencies of 60.71 and 75.89 were obtained for mLBD1 and mLBD2 dyes, respectively. The energy conversion efficiencies of mLBD1 and mLBD2 dyes are 3.15 (J S C = 11.86 mA/cm2, V O C = 613 mV, f f = 0.4337) and 3.36 (J S C = 12.71 mA/cm2, V O C = 655 mV, f f = 0.4042), respectively, measured at the AM1.5G conditions, the reference black dye-sensitized solar cell, fabricated and evaluated under identical conditions exhibited η-value of 2.69 (J S C = 10.95 mA/cm2, V O C = 655 mV, f f = 0.3750). © 2011 Malapaka Chandrasekharam et al.