| 초록 |
We synthesized a novel low-band gap conjugated polymer, poly[4,7-bis(3’,3’-diheptyl-3,4-propylenedioxythienyl)-2,1,3-benzothiadiazole] [poly(heptyl4-PTBT)] consisting of alternating electron-rich diheptyl-substituted propylene dioxythiophene and electron-deficient 2,1,3-benzothiadiazole units and its photovoltaic properties were investigated. The thin film of poly(heptyl4-PTBT) exhibits an optical band gap of 1.55 eV. And also, new thermally robust photoactive arylenevinylene-based conjugated polymers, poly[3,6-bis(3,7-dimethyloctyloxy)-9,9-spirobifluorenyl-2,7-vinylene] [(OC10)2-Spiro-PFV] and poly[{3,6-bis(3,7-dimethyloctyloxy)-9,9-spirobifluorenyl-2,7-vinylene}-co-2-{methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene}] [(OC10)2-Spiro-PFV-co-MEH-PPV], were synthesized and used to fabricate polymer solar cells. Bulk heterojunction solar cells fabricated by blending the new polymers, poly(heptyl4-PTBT), Spiro-PFV and (OC10)2-Spiro-PFV-co-MEH-PPV, as an electron donor with the fullerene derivative [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as an electron acceptor. The effects of electron donor to acceptor ratio, thickness of photoactive layer, and the cathode structures on the power conversion efficiency (PCE) in solar cells were studied. The copolymer feed ratio was found to have a considerable effect on the PCE. The maximum PCE of 0.35 % with poly(heptyl4-PTBT) and 1.30% was achieved with (OC10)2-Spiro-PFV-co-MEH-PPV. |
