In Situ Synthesis and Characterization of Poly(aryleneethynylene)-Grafted Reduced Graphene Oxide

Abstract

Using highly soluble bromo-functionalized reduced graphene oxide (RGBr) as a key graphene template for surface-directing Sonogashira-Hagihara polymerization, a novel soluble poly(arylene-ethynylene)-grafted reduced graphene oxide, hereafter abbreviated as PAE-g-RGO, was prepared in situ. The entirely different electron distribution of LUMO and HOMO of PAE-g-RGO suggested the existence of a charge-transfer (CT) state (PAE(.-) -RGO(.+) ). The negative ΔGCS value (-2.57 eV) indicates that the occurrence of the charge separation via (1) RGO* in o-DCB is exothermic and favorable. Upon irradiation with 365 nm light, the light-induced electron paramagnetic resonance (LEPR) spectrum of PAE-g-RGO showed a decrease in the spin-state density owing to photoinduced intramolecular electron transfer events in this system. A sandwich-type Al/PAE-g-RGO/ITO device showed representative bistable electrical switching behavior. The nonvolatile memory performance was attributed to the CT-induced conductance changes, which was supported by molecular computation results and conductive atomic force microscopy (C-AFM) images.

Keywords: covalent modification; in situ polymerization; poly(aryleneethynylene); reduced graphene oxide; structural characterization.