“…Figure 1 a shows the main IR bands of P3HT, which are peaked at 723, 810, 1032, 1165, 1462, 1510, 1735, 2854, 2924 and 3113 cm −1 , they being assigned to the following vibrational modes: rocking CH 2 , out of plane bending C-S in thiophene ring α, α’ disubstituted, aromatic C-H stretching, thiophene ring, asymmetrical C=C in thiophene ring, C=O stretching, symmetric C-H stretching in CH 2 moieties, C-H in hexyl group and sp 2 C-H stretching in aromatic compounds, respectively [ 8 , 21 ]. The IR bands at 617 and 1381 cm −1 were attributed to the vibrational modes of the distorted parts of polymer and the deformation of -CH 3 group belonging to the defects present in the P3HT macromolecular chains, respectively [ 22 , 23 ].…”