A dendronised polymer for bulk heterojunction solar cells

A Gilch polymerisation was used to form a high molecular weight poly[1,4-phenylenevinylene] with pendent first generation biphenyl dendrons attached to every monomer unit of the backbone. The attachment of the bulky side-chain was found not to disrupt the conjugation of the polymer backbone and the polymer formed an ordered intramolecular structure in the solid-state. Bulk heterojunction (BHJ) organic solar cells were manufactured by blending the polymer at different ratios with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Under AM1.5 testing conditions the device with the polymer:PCBM ratio 1 : 3 by weight was found to have an optimum Voc = 0.86 V, Jsc = 1.4 mA cm−2, FF = 37% and PCE of 0.44%, with the PCE 30 times higher than the only other report on a dendronised polymer used in a BHJ device.