Plastic Solar Cells Based on Novel PPE-PPV-Copolymers

In this study plastic solar cells based on arylene-ethynylene/arylene-vinylene hybrid polymers in combination with the soluble fullerene PCBM (1-(3-methoxycarbonyl) propyl-1-phenyl [Citation6 Citation6]C61) reaching 2% AM 1.5 solar power conversion efficiency at 80 mW/cm2 are reported. The polymers used are DE105 (poly(-2,5-dioctyloxy-1,4-phenylene-diethynylene-2,5-dioctyloxy-1,4-phenylene-vinylene-2,5-di(2′-ethyl)hexyloxy-1,4-phenylene-vinylene)) and DE142 (poly(2,5-dioctyloxy-1,4-phenylene-ethynylene-9,10-anthracenylene-ethynylene-2,5-dioctyloxy-1,4-phenylene-vinylene-2,5-di(2′-ethyl)hexyloxy-1,4-phenylene-vinylene)), whose main difference lies in the additional anthracene group in the latter one. Comparing results from electrochemical characterizations with IV-measurements reveals a weak dependency of the maximum open circuit voltage on the molecular HOMO level of the polymer used. A coarse grained morphology of the active layers was found responsible for limiting the photocurrent, as shown by AFM measurements.