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

•The dyes containing various amine-typed donors were synthesized and used for DSSC.•The SGT-103 containing bis-phenothiazinylamine has a good light-harvesting ability.•The SGT-102 had a better prevented charge recombination than other dyes.

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 12.1 mA cm−2, Voc 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 Jsc and Voc, leading to a lower efficiency of 5.16%, due to slow charge recombination associated with differently geometric structure orientations.

Graphical abstractThree SGT organics dyes, which have triphenylamine, bis-dimethylfluorenylamine and bis-dihexylphenothiazinylamine as electron donor groups, were designed and synthesized for application in dye-sensitized solar cells (DSSCs) employing cobalt electrolyte.Figure optionsDownload full-size imageDownload as PowerPoint slide