As illustrated in Fig. 3a, epitaxial growth of P3HT on K-BrBz leads to highly
crystalline, oriented and nanotextured P3HT films that consist of a regular network
of interconnected semicrystalline domains oriented along two preferential in-plane
directions. The overall crystallinity and the level of in-plane orientation of the
P3HT films are controlled by the temperature of isothermal crystallization (T iso ).
Well-defined ED patterns with sharp reflections obtained for T iso ¼ 180
C (see
Fig. 3b) indicate that the crystalline domains grow with a unique (1 0 0) P3HT contact
plane on the K-BrBz substrate (’edge-on’ orientation of the conjugated backbone
on the substrate). The P3HT chains are oriented along two preferred in-plane
Fig. 2 (a) Three main steps of the oriented P3HT film preparation on aromatic salt crystals. (b)
TEM-BF image showing an oriented and nanostructured P3HT film after removal of the K-BrBz
substrate. The shape of the oriented P3HT film reproduces the initial rhombic-shaped K-BrBz
crystal. (c, d) POM images of an oriented area of P3HT grown epitaxially on K-BrBz (T ¼ 180
C).
The remaining epitaxied P3HT area has the initial lozenge shape of the K-BrBz crystal. The
epitaxied P3HT area shows a variation in the absorbance versus orientation of the incident light
polarization (double arrow). (Reprinted with permission from [42] © 2010, American Chemical
Society)
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