Figure 3: Domain purity data and analysis.
From: Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells
(a) R-SoXS results revealing relative purity of PffBT4T-2OD:ICMA and (b) PffBT4T-2OD:PC71BM blends annealed at 130 °C. (c) Following methodology developed by Collins et al.,40 residual ICMA in PffBT4T-2OD is only 3.2% after a PffBT4T-2OD:ICMA blend has been annealed extensively until all excess ICMA has agglomerated into macro-phase domains or crystals. Red lines/symbols are near edge X-ray absorption fine structure data/uncertainty and black lines are fits. Yellow and blue lines are PffBT4T-2OD and fullerene reference spectra used in the fit. Error bars represent the average of three different spots on the sample. A value of 3.2% indicates that there are 3.2% (w.t) fullerene in the average polymer domains that includes polymer crystals and the mixed, amorphous phase.
