Syntheses of triphenylamine-based organic dyes and effects of their acceptor groups on photovoltaic performances of dye sensitized solar cells

We synthesized two organic dyes, (3-(5-(4-(bis(4-bromophenyl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid (TPA-T1) and 3,3′-(5,5′-(4,4′-(4-bromophenylazanediyl)bis(4,1-phenylene))bis(thiophene-5,2-diyl))bis(2-cyanoacrylic acid) (TPA-T2)), which contain the triphenylamine moiety as an electron donor and cyanoacrylic acid moiety as an electron acceptor, connected by thiophene units. Nanocrystalline TiO2-based dye sensitized solar cells (DSSCs) were fabricated using these dyes to confirm the effects of the number of electron acceptors (single or double) on their photovoltaic performance. The DSSC devices based on the TPA-T2 dye showed higher overall efficiencies (η = 2.68–4.11%) than those based on TPA-T1 (η = 2.54–3.46%) due to its the superior optical properties.

► Triphenyl amine dyes with thiophene units for dye sensitized solar cells.
► Triphenyl amine dye with double electron acceptor showed red-shifted absorption peak.
► Photovoltaic performances of DSSC depend on number of electron acceptors on organic dyes.