• crystallization;
  • fullerenes;
  • polymer solar cells;
  • structure-property relations;
  • X-ray diffraction


Thumbnail image of graphical abstract

Polymer/fullerene bulk heterojunction solar cells consisting of PDDTP:PCBM blends have been investigated and optimized. The structural properties of the photoactive layers were studied by GID-XRD, which revealed a pronounced response of photovoltaic parameters on the polymer crystallinity. In addition to P3HT, another donor polymer was found that develops crystalline domains upon annealing. We found a clear correlation between annealing time, power conversion efficiency, and polymer crystallinity. The PDDTP crystallization ability is a promising property. This is a first step toward the synthesis of low-bandgap polymers, which likewise show the ability to form crystalline domains and may therefore lead to a substantial increase in efficiency.