Low-band gap poly(di-2-thienylthienopyrazine):fullerene solar cells

Two side-chain substituted poly(di-2-thienylthienopyrazine)s (PBEHTT and PTBEHT) are used as electron donor together with phenyl-C61 butyric acid Me ester (PCBM) as an electron acceptor in low-band gap bulk heterojunction polymer solar cells. These low-band gap polymers absorb light up to .apprx.1 mm. Under simulated AM1.5 conditions PTBEHT:PCBM devices provide a short circuit current of Jsc = 3.5 mA/cm2, an open circuit voltage of Voc = 0.56 V, and a power conversion efficiency of h = 1.1%. Photoresponse up to 1 mm was obsd. with external quantum efficiencies exceeding 15% in the 700-900 nm region. [on SciFinder (R)