Synthesis and investigation of anchoring unit effect in blue-colored isoindigo-based D-A-pi-A organic dyes for dye-sensitized solar cells

Isoindigo-based blue colored organic dyes (IND-B, IND-T, and IND-I) with different electron acceptors such as 2-cyanoacetic acid/carboxylated 1,3-indandione bridged through benzene or thiophene pi-spacers were synthesized and applied in dye-sensitized solar cells (DSSCs). The photoelectrochemical performances and charge transport properties revealed that the device fabricated with IND-B sensitizer showed the highest power conversion efficiency of 3.37% among the three dyes. The diminished performance of IND-T and IND-I is partially attributed to the relatively lower lying LUMO level. The designated charge transport of the synthesized dyes secured from electrochemical impedance spectroscopy (EIS) analysis were found to be in accordance with experimentally attained photovoltaic parameters. (C) 2018 The Japan Society of Applied Physics