Organic photovoltaic devices are typically a blended system containing a polymer as the electron donor and a fullerene acceptor. One challenge in these devices is to maximize the crystallinity of each component of the blended system to increase the mobility of photogenerated charge carriers. We have used 100% regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) with a polydispersity approaching unity in combination with sequential processing to maximize the crystallinity of the polymer phase. We are able to study the crystallinity of the both the polymer and fullerene phases using x-ray diffraction of the highly crystalline P3HT and a commercially available P3HT. In this study, in-situ annealing was also performed to characterize the change in morphology for devices fabricated using sequential processing and those fabricated by conventional bulk heterojunction methods. By measuring device efficiencies, we are then able to compare how the propensity of the polymer to crystallize and subsequent fullerene intercalation can influence photovoltaic performance.

Optimizing morphology in organic photovoltaic devices by controlling polymer crystallinity

243rd National Meeting (2012)

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