Using this approach to deposit thin uniforms films, we investigated the solid-state morphology of blend films blade coated at low (25 °C) and high (105 °C) substrate temperatures using GIWAXS. In Fig. , we show the 2D GIWAXS images of the blend films printed at 25 °C where all blend films exhibit in and out-of-plane (010) peaks at around q ~ 1.8 Å -1 (d = 3.5 Å) which correspond to face-on and edge-on π-π stacking with respect to the substrate. We attribute the π-π stacking peaks to the polymer backbone stacking because all neat polymer films possess (010) peaks while the neat acceptor film has an amorphous halo which does not contribute to the observed π-π stacking peak of the blend film (Fig. ). Furthermore, we also demonstrate that all blend films show lamellar stacking peaks (100) around q ~ 0.3 Å -1 (d = 2.1 nm) based on Fig. where the color scale of the scattering patterns in Fig. is adjusted to clearly show (100) reflections. When a high substrate temperature of 105 °C is used as the coating temperature, we observe that the face-on π-π stacking peak in the PM7:ITIC-4F blend film is substantially enhanced as shown in Fig. . This qualitative observation indicates that the molecular orientation could be highly sensitive to the substrate temperature. To further quantify and compare the polymer orientation distribution amongst the three polymer blend films, we performed molecular orientation analysis which follows the procedures described in earlier works. The pole figures shown in Fig. are obtained by plotting the intensity of the (010) peak as a function of the azimuthal angle, χ, with 10° interval starting from 0° to 90° which represents face-on and edge-on crystallites respectively. The (010) peak intensity at each angle is obtained by peak deconvolution due to the overlap of the amorphous and π-π stacking peaks as previously reported. The obtained peak intensities are then normalized by their exposure time and irradiated volume and multiplied with 𝑠𝑖𝑛𝜒 which corrects the intensity underestimation at high χ due to the scattering geometry. Based on the analysis, we observe that the molecular orientation of the PM7:ITIC-4F blend film is indeed highly sensitive to the coating temperature as shown in Fig. in which the polymer orientation switches from more isotropic population to a population with predominantly face-on orientation as illustrated in Fig. . On the other hand, in the PM7 D1 and D2 blend films, we observe only a slight enhancement of the face-on population (Fig. ). The extent of molecular orientation change can be more clearly quantified by calculating the Herman's orientation parameter (S) from the (010) π-π stacking peak. The S parameter ranges from a value of -0.5 which corresponds to a complete edge-on population to a value of 1 which is a total face-on population. The S value of 0 corresponds to a mixture of both face-on and edge-on orientations. Based on Fig. , the PM7 blend film printed at 25 °C shows a value of 0.098 which represents an isotropic population whereas the PM7 D1 and D2 blend films printed at 25 °C are more face-on with S values of 0.173 and 0.145, respectively. At a high coating temperature of 105 °C, there is a substantial increase in the S value for PM7 reaching 0.205 while a slight improvement is observed for PM7 D1 and D2, indicating their molecular orientation in the solid-state is less dependent on the substrate temperature as compared to PM7. We attribute this isotropic orientation of the PM7 blend film printed at 25 °C to the large fiber-like aggregates observed in solution which may already possess the thermodynamically favorable molecular orientation in the solution-state. To investigate the phase separation of the blend films, we use Resonance Soft X-ray Scattering (RSoXS) whereby the X-ray energy can be tuned to the aromatic C1s→π * to improve the contrast between the donor and acceptor domains. An X-ray energy of 284.8 eV is selected due to the high scattering contrast between the donor and acceptor domains as demonstrated by the scattering profiles at various X-ray energies in Fig. . From the raw scattering data, the SiN substrate background is then subtracted to give the scattering profiles as shown in Fig. . To determine the domain size, the cylinder model is applied assuming that the shape of the domains resembles a cylinder since polymer chains and the fibers in solution are modeled as flexible or rigid cylinder as previously discussed in fitting the SAXS results. As we see from Fig. , the cylinder model works well with fitting the RSoXS scattering data providing the radius and length of the domains as fitting parameters which are tabulated in Table . For a PM7 blend film printed at room temperature, we applied a two-cylinder based model (small and large cylinder) to better fit the scattering data as shown in Fig. . Applying the two-cylinder model resulted in two domains with an average radius of 17.7 nm and 9.4 nm which are likely formed from large fiber aggregates and polymer network-like aggregates co-existing in the 25°C solution as previously discussed for PM7 solution SAXS results. On the other hand, in the PM7 D1 and D2 blend films, there is only one dominant small cylinder population with a radius of 8.3 nm and 9.7 nm, respectively. Based on the radius (R) and length (L), we determine the radius of gyration (𝑅𝑔 = 𝑅 12 + 𝐿