A highly efficient PTB7-Th polymer donor bulk hetero-junction solar cell with increased open circuit voltage using fullerene acceptor CN-PC_(70)BM

摘要

Modified [6,6]-phenyl-C_(70)-butyric acid methyl ester (CN-PC_(70)BM) is employed as an electron acceptor along with poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b; 4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th) polymer as donor for solution-processed organic solar cells. Inverted device architecture is adopted to fabricate the photovoltaic devices. Using chloronaphthalene as an additive, a high power conversion efficiency (PCE) of 8.2% is achieved with an excellent open circuit voltage (V_(oc)) of 0.9 V, short-circuit current density (J_(sc)) of 13.5 mA cm~(-2) and fill factor of 0.68 as compared to PCE of 5.4% from the reference solar cell using PC_(70)BM.