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

Abstract

Two side-chain substituted poly(di-2-thienylthienopyrazine)s (PBEHTT and PTBEHT) are used as electron donor together with phenyl- C61 butyric acid methyl ester (PCBM) as an electron acceptor in low-band gap bulk heterojunction polymer solar cells. These low-band gap polymers absorb light up to ∼1 μm. 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 η=1.1%. Photoresponse up to 1 μm has been observed with external quantum efficiencies exceeding 15% in the 700-900 nm region. © 2006 American Institute of Physics.