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Abstract
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Reduced graphene oxide (rGO) and its derivatives functionalized with 2-thiophene acetic acid (rGO-f-TAA) and
grafted with poly (3-dodecylthiophene) (rGO-g-P3DDT) and poly (3-thiophene ethanol) (rGO-g-PTEt) were
prepared to design the donor-acceptor supramolecular structures based on the regioregular poly (3-hexylthiophene) (P3HT). The P3HT nanofibers, which were pre-grown in a separate system and possessed theπ-stacked P3HT backbones in the length of fibrils, were perpendicular to the rGO surface in the solution and,
consequently, they inclined onto the substrate during solvent evaporation. Through this inclination, the orientation of P3HT chains changed from face-on to edge-on. In rGO-f-TAA systems, for either short (80 nm) or
long (420 nm) P3HT nanofibers, the P3HT nanofibers were attached from their sides onto the rGO. The appearance of (020) and (002) spots in selected area electron diffraction (SAED) patterns proved afixed edge-on
orientation even after solvent evaporation. Functionalization of rGO surface with 2-thiophene acetic acid altered
the tethering tendency of P3HT chains from the thiophenic rings to the hexyl side chains. Via grafting the rGO
with P3DDT and PTEt, the tethered P3HT nanofibers were perpendicularlyfixed onto its surface with a face-on
orientation having (002) and (100) spots even after solvent evaporation, resulting in the conductivity range of
9.9–10.9 S/cm. The pre-developed large single crystals were also employed to construct the donor-acceptor
supramolecules with edge-on oriented P3HTs. Further tethering of P3HT fibrils onto the rGO based micron
sheets reflected a red-shifting and more intensified A0–2,A0–1, and A0–0peaks in the ultraviolet–visible spectra. A
quenching in the photoluminescence spectra was observed in longer preparation time (18 h) based on the charge
transferring from donor (P3HT) to acceptor (rGO derivatives).
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