Figure 3. Characterization of phase-separated morphology in blend thin films via RSoXS.

(a) Two-dimensional scattering images of reference versus FLUENCE films prepared at 25 μm s⁻¹. The intensity is plotted in log scale, with white, brown, yellow, green ranging from high to low intensities. (b) Integrated intensity profiles of reference versus FLUENCE films prepared at various printing speeds. Data corresponding to 100 μm s⁻¹ printing speeds closely resemble those at 75 μm s⁻¹ and are therefore omitted. To compare the scattering anisotropy, intensity from the vertical sector (parallel to the beam polarization direction) is compared with that from the horizontal sector (perpendicular to the beam polarization direction) and the circular average. The vertical (red) and horizontal (green) sectors correspond to the highlighted regions in figure (a). (c) Radius of gyration from Guinier analysis assuming spherical domains. R_g is calculated by fitting the scattering data with I(q)=I₀ exp(−q²R_g²/3). The error bars displayed were calculated from s.e. of the fitted parameter R_g. The fitted R_g values are summarized in Supplementary Table 2. The analysis was performed over a q range of 0.001–0.007 Å⁻¹. Beyond this range, poor linearity was found in ln(I) versus q² plot. Due to this poor linearity and the weak scattering intensity, the higher q feature is not quantitatively analysed but is instead illustrated schematically in d. The corresponding Iq² versus q plots (vertical sector) are shown in Supplementary Fig. 4. (d) Schematic illustrating the possible in-plane morphology. The schematic is simplified, and the domain connectivity is not shown. The blue medium denotes the amorphous electron-acceptor polymer, P(TP). The red domains represent electron donor PII-tT-PS5, forming amorphous (shown without red bars) and semicrystalline domains (with red bars) The semicystalline domains are not crystallites but are likely aggregates of crystallites, possibly separated by small amorphous regions.