Amide-linked hole transporting material for solid-state dye-sensitised solar cells

This paper reports the first use of an amide-based hole transport material in a solid-state dye-sensitised solar cell. A substantial improvement in solar cell efficiency from 0.04 to 2.26% was achieved through prolonged oxidation in air and light soaking for the amide-based hole-transporting mediator, TPABT. Time-resolved spectroscopic studies show that the oxidation state and additive concentration alter the charge-transfer and regeneration kinetics, which are consistent with the time-dependent changes in device properties. Our study shows that, if the oxidation state and doping are carefully controlled, TPABT-based hole transport materials could serve as a viable, cost-effective alternative to Spiro-OMeTAD, the conventional yet expensive hole-transporting material widely used in emerging photovoltaics.