A-D-A-D-A-Type Oligothiophenes for Vacuum-Deposited Organic Solar Cells

Novel A-D-A-D-A-type oligothiophenes incorporating electron-withdrawing benzo[c][1,2,5]thiadiazole (BTDA) as core and trifluoroacetyl (TFA) as terminal acceptor groups have been developed. Vacuum-processed planar heterojunction organic solar cells incorporating these new oligomers as donor and C-60 as acceptor showed very high open circuit voltages up to 1.17 V, resulting in power conversion efficiencies of 1.56% under AM1.5G conditions.