초록 |
Low–band-gap organic semiconducting polymers comprising two dialkoxy-substituted benzoselenadiazole derivatives and two BDT derivatives as the electron acceptors and donors, respectively. The polymers were thermally stable, i.e., lost <5% of their weight upon heating to ~300 °C. Intramolecular charge transfer between the electron-donating and -accepting blocks of the polymeric backbone induced a broad absorption from 300–750 nm. The optical band gap energies were 1.74−1.67 eV depending on the structure of the polymer. Bulk hetero-junction photovoltaic devices using the polymers with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the electron acceptor were fabricated; one device showed a high power conversion efficiency of 3.57% with an open-circuit voltage of 0.77 V, a short-circuit current of 11.03 mA/cm2, and a fill factor of 0.42 under AM1.5G illumination (100 mW/cm2). |