High efficiency organic solar cells with spray coated active layers comprised of a low band gap conjugated polymer

Airbrush is a promising tool for large scale organic thin film deposition in photovoltaic devices fabrication. This paper reports a detailed study on solar cell performance using airbrush spray deposition for active layer composed with recently developed low band gap donor material poly[4,8-bis(1- pentylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-2,1, 3-benzoxadiazole-4,7-diyl and [6,6]-phenyl-C61-butyric acid methyl ester. The effect of carrier solvent and substrate temperature on film morphology are studied; a formula in 1,2-dichlorobenzene sprayed at a substrate temperature of 80° C is found to be the optimum condition that produces a peak power conversion efficiency of 5.8.