New N-methyl pyrrole and thiophene based D–π–A systems for dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) containing novel DP-T and DP-P organic sensitizers having thiophene and N-methyl pyrrole moieties as π bridges in a D–π–A system were assembled and characterized. Incorporation of a thiophene bridge to give sensitizer DP-T enhanced solar energy capture, while impedance spectroscopy showed a much longer electron recombination lifetime (τ) for the DSSCs based on pyrrole containing sensitizer DP-P. The observed kinetics led to increased open circuit voltage (Voc) for the device based on DP-P, regardless of types of additives (TBP or DCA) employed in the devices. Better photovoltaic performance was achieved using DP-T.

► New sensitizers having N-methyl pyrrole or thiophene π-spacers were incorporated into DSSCs.
► The DSSC device based N-methyl pyrrole showed good kinetic properties, resulting in a high Voc.
► Molecular modeling studies were used to predict electronic energies and densities.