Photoreactive low-bandgap 4H-cyclopenta[2,1-b:3,4-b′]dithiophene and 4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole-based alternating copolymer for polymer solar cell

摘要: Abstract Polymer solar cells (PSCs) are often fabricated using a well-known 4H-cyclopenta[2,1-b:3,4-b′]dithiophene and 4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole-based polymer as low-bandgap polymer. Further, PSCs also by mixing methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PC61BM) with the We prepared poly[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b′]dithiophene-2,6-diyl-alt-4,7-bis(2-thienyl)-2,1,3-benzothiadiazole-5′,5′′-diyl] after anchoring penta-1,4-diene in side chain of cyclopentadithiophene investigated long-term performance stability photocrosslinked bulk heterojunction (BHJ) photovoltaic (PV) cell based on The photocrosslinking reaction was monitored via infrared spectroscopy without use photoinitiator, carrying out spontaneous radical coupling reaction. film has broad absorption band extending from 300 to 850 nm an optical bandgap low 1.52 eV. employed fabricate PSC PC61BM. resultant device, which treated UV irradiation (λ = 254 nm, I = 40 mW/cm2, 5 min), had good preliminary results open-circuit voltage 0.62 V, short-circuit current density −5.37 mA/cm2, fill factor 0.41, overall power conversion efficiency 1.37%. All parameters UV-cured device were more stable over course 300 h than those P3HT-PC61BM devices, indicating