New panchromatic dyes comprising benzothiadiazole units within a donor–acceptor π-conjugated spacer. Synthesis and photophysical properties

New dyes for DSSC containing triphenylamine based extended donor: Synthesis, photophysical properties and device performance

Three new triphenylamine based dyes with Donor-Donor-Spacer-Acceptor (D-D-π-A) arrangement were designed and synthesized by convenient synthetic pathway. Unsymmetrical extended donor part may help to reduce the aggregation of dyes on the semiconductor surface. Wide range of absorption in the visible spectrum, electrochemical studies and theoretical optimization suggest that these dyes can be good members for DSSC. Further to check the performance of these dyes in device the solar cells were developed using iodine free Co-based electrolyte. Electronic characterisation concludes that devices based on D6 have the highest power conversion efficiency (4.7%) mostly due to an improved electron lifetime, which therefore improves both the V_OC and J_SC of the devices.

Impact of strength and size of donors on the optoelectronic properties of D–π–A sensitizers

A series of carbazole based sensitizers have been synthesized to understand the influence of the strength of the donor moiety on the optical, electrochemical and photovoltaic properties.