Molecular Design to Improve the Performance of Donor-π Acceptor Near-IR Organic Dye-Sensitized Solar Cells

A novel near-IR charge-transfer complex, as a D-π-A-type mol., has a lateral anchoring group and a flexible long carbon chain that replaces the Me group of the donor part of the mol. This carbon chain seems to prevent the formation of mol. aggregates on the semiconductor (TiO2) nanoparticles, thus blocking charge recombination at relatively high open-circuit voltages and short-circuit photocurrent densities. This sensitizer dye has a max. IPCE (incident-photon-to-current conversion efficiencies) of 93% at 660 nm and an overall solar-energy-to-electricity conversion efficiency of 5.1%.