Solvent-Annealed Crystalline Squaraine: PC70BM (1:6) Solar Cells



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It is demonstrated that squaraine:PC70BM blends can result in solar cells with high efficiency and fill factor when the nano­structure scale is increased to lead to conduction of photogenerated carriers to the electrodes. Morphological control occurs by a combination of thermal and solvent annealing of these small molecule, solution-processed bulk heterojunction cells. Peak efficiencies of a population of devices is 5.2% at fill factors of 0.5 are achieved under optimized conditions.