A red to blue series of push-pull dyes for NiO based p-DSSCs.

Abstract : Finding efficient dyes for NiO photocathodes either for inverse or tandem DSSCs is essential to develop these promising low-cost solar cells. This paper reports the design, the synthesis and the physical properties characterization of four new triphenylamine-bithiophene push-pull dyes with acceptors of increasing electronic affinity, in order to shift their absorption to the red region of the visible spectrum. The dyes were tested in p-type DSSC configuration with 850 nm NiO ink-jet printed photocathodes and their performance were compared with the reference dye P1. With an iodine electrolyte, one of the dyes, possessing a 1,3-diethyl-2-thiobarbituric acceptor shows superior performance than P1, with a PCE reaching 0.124% and a JSC of 4.32 mA.cm-2.