A novel blue dye for near-IR 'dye-sensitised' solar cell applications.

A squaraine dye incorporating two carboxylic acid attaching groups has been synthesised and used successfully in both liquid and solid-state solar cells, with solar energy to electricity conversion efficiencies (eta) under AM 1.5 G irradiation (100 mW cm(-2)) of 3.7 and 1.5% and short-circuit current densities (J(sc)s) of 8.6 and 4.2 mA cm(-2), with open-circuit voltages (V(oc)) of 591 and 681 mV and fill factors (FF) of 73 and 53%, respectively.