D–π–A organic dyes with various bulky amine-typed donor moieties for dye-sensitized solar cells employing the cobalt electrolyte

Abstract

SGT dyes containing various amine-typed donors as triphenylamine, bis-fluorenylamine and bis-phenothiazinylamine as the electron donor and a cyanoacrylic acid moiety as electron acceptor in D–π–A system, were developed to use in dye-sensitized solar cells (DSSCs). The SGT-102 dye containing bis-fluorenylamine had a better prevented charge recombination than other SGT dyes; leading to improvement in Voc. As a result, the conversion efficiency of 7.22% was achieved with a Jsc of 12.1mAcm−2, Voc of 865mV and a FF of 69.1 for the DSSC employing a dye containing the bulky bis-fluorenylamine donor unit, while the DSSC based on a dye containing the bulky bis-phenothiazinylamine donor unit showed a lower Jsc and Voc, leading to a lower efficiency of 5.16%, due to slow charge recombination associated with differently geometric structure orientations.