Figure 5
Two-dimensional-grazing incidence X-ray diffraction (2D-GIXRD) patterns of DC-P3HT(a) and TCB-treated P3HT(b) obtained at an incidence angle of 0.2° with the synchrotron X-ray source and (c), (d) are the 1D diffraction profile with respect to the out-of-plane (along the qz) direction and in-plane (along the qxy) direction extracted from 2D-GIXRD pattern of (a) and (b), respectively. In DC-P3HT, the observed three strong (h00) diffraction peaks and a weak (010) peak along the Debye rings indicating its polycrystalline structure with mostly ‘edge-on’ crystallites and a small amount of ‘face-on’ crystallites. In TCB-treated P3HT, there is coexistence of a strong (010) π–π stacking peak (~3.8 Å) as well as (h00) peaks along both the qz and qxy, and the intensity ratio of (010) π–π stacking peak to (h00) peak increased compared with the DC-P3HT, which indicates that the amount of ‘face on’ crystallites increased during the TCB-treated crystallization process. The increased amount of ‘face-on’ crystallites of TCB-treated P3HT is attributed to the mutual orientation of polymer backbones on both crystal surfaces along the c axis of TCB crystals during the crystallization process.
