To investigate the structure-dependent aggregation behavior of conjugated polymers and the effect of aggregation on the device performance of conjugated polymer photovoltaic cells, new conjugated polymers (PVTT and CN-PVTT) having the same regioregularity but different intermolecular packing were prepared and characterized by means of UV−vis spectroscopy and atomic force microscopy (AFM). Photovoltaic devices were prepared with these polymers under different polymer-aggregate conditions. Polymer aggregation induced by thermal annealing increases the short circuit current but provides no advantage in the overall power conversion efficiency because of a decrease in the open circuit voltage. The device fabricated from a pre-aggregated polymer suspension, acquired from ultrasonic agitation of a conjugated polymer gel, showed enhanced performance because of better phase separation and reduced recombination between polymer/PCBM.Keywords (keywords): conjugated polymers; nanowires; organic electronics; organic photovoltaic cells; self-assembly

Triazole based structural units have been widely used to construct conjugated polymers for optoelectronic applications; yet the design and synthesis of such units have been limited to just a few known examples. We report a general yet versatile synthetic approach toward a diverse set of triazole based conjugated molecules bearing various electron accepting abilities. The structural differences of as-synthesized three new triazole acceptors have a significant impact on the optoelectronic properties of conjugated polymers incorporating these triazoles. Bulk heterojunction solar cells based on one of these new polymers, PyCNTAZ, feature a high open circuit voltage of ∼1 V and a notable efficiency of 8.4% with an active layer thickness around 300 nm.