Purposive Assembling of Poly(3-hexylthiophene) onto Chemically Treated Multi-Wall Carbon Nanotube versus Reduced Graphene Oxide

Abstract

Surfaces of multi-walled carbon nanotubes (CNTs) and reduced graphene oxide (rGO) nanosheets were chemically modified to design distinct donor-acceptor nano-hybrids having different morphologies and orientations. In unmodified CNTs and their derivatives functionalized with 2-hydroxymethyl thiophene (CNT-f-COOTh) and grafted with poly(3-dodecylthiophene) (CNT-g-PDDT), double-fibrillar, shishkebab, and stem-leaf nanostructures were decorated. Furthermore, rGO nanosheets functionalized with 2-thiophene acetic acid (rGO-f-TAA) and grafted with poly(3-dodecylthiophene) (rGO-g-PDDT) were prepared to study differences in CNT and rGO supramolecules. Three types of orientations subsuming face-on, edge-on, and flat-on were detected in nano-hybrids based on CNT and rGO. Morphology (fibrillar) and orientation (face-on) of poly(3-hexylthiophene) (P3HT) assemblies were similar onto unmodified CNT and rGO nanostructures. Although patternings of P3HT chains were completely different onto functionalized CNT and rGO (shish-kebab versus nanocrystal decorated nanosheets), edge-on orientation was detected in CNT-f-COOTh/P3HT and rGO-f-TAA/P3HT nano-hybrids. In CNT-g-PDDT/P3HT and rGO-g-PDDT/P3HT systems, P3HT chains were extendedly assembled onto grafted carbonic materials; however, their different natures reflected stem-leaf and patched-like configurations, respectively. For unmodified, functionalized, and grafted CNT and rGO patterned with P3HT chains, a photoluminescence quenching was detected for a donor-acceptor nature. Owing to flat-on oriented P3HTs, the best photoluminescence quenching, thereby the best donating-accepting features were detected for CNT-g-PDDT/P3HT and rGO-g-PDDT/P3HT supramolecules.