Exploring the synergy between copper electrolytes and molecularly engineered thiocyanate-free cyclometalated ruthenium sensitizers for dye-sensitized solar cells.

Two novel cyclometalated ruthenium complexes, RC-4 and RC-5, featuring 1-phenylisoquinoline and phenyl quinazoline as ancillary ligands, respectively, were synthesized to investigate their viability with the environmentally friendly copper (Cu) redox mediator, [Cu(bpye)]. The modification of the ligand environment resulted in variations in the energetics, photophysical properties, and photovoltaic performance of RC-4 and RC-5 sensitizers. Despite RC-5 sensitizer possessing a more positive ground state potential of 1.

Regulating Back Electron Transfer through Donor and π-Spacer Alterations in Benzothieno[3,2-b]indole-based Dye-sensitized Solar Cells.

Three metal-free organic D-π-A dyes with benzothieno[3,2-b]indole as electron donor, cyanoacrylic acid as both electron acceptor and anchoring group with benzene (BID-1), thiophene (BID-2) and furan (BID-3) as π-spacers were designed and synthesized for application in dye-sensitized solar cells (DSSCs). A planar and electron-rich heterocycle such as benzothieno[3,2-b]indole offers better backbone rigidity and improves charge transport properties in comparison to indolo[3,2-b]indole donor, previously reported from our group. Additionally, we synthesized a benzothieno[3,2-b]indole donor grafted with longer alkyl chains which efficiently prevented the approach of oxidized species in the electrolyte coming closer to semiconductor thereby arresting recombination.