D-pi-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-pi-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 V-oc. As a result, the conversion efficiency of 7.22% was achieved with a Jsc of 12.1 mA cm(-2), V-oc of 865 mV 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 J(sc) and V-oc, leading to a lower efficiency of 5.16%, due to slow charge recombination associated with differently geometric structure orientations. (C) 2015 Elsevier B.V. All rights reserved.