Influences of Polymer Residues on the Growth Properties of Pentacene Thin Film on Graphene Substrates

Abstract

Understanding of the growth properties of organic thin film (OTF) on graphene surface is beneficial to develop high-performance organic electronic devices based on OTF and graphene electrodes. In this work, we investigated the growth behaviors of pentacene on the poly(methyl methacrylate) (PMMA)-assisted wet-transfer graphene substrates. Especially, the influence of PMMA residues and graphene wrinkles on the initial nucleation behavior and subsequent aggregation of pentacene were studied in detail. Pentacene adopts standing-up geometry on the as-transferred graphene substrates. The molecules prefer to initially reside beside graphene wrinkles where the density of PMMA residues is found to be larger than the flat regions of graphene and then the subsequent deposited pentacene was packed face-to-face and developed into one-dimensional fiberlike domains with a fiber length of few micrometers. Controlled experiments and detailed surface analysis of graphene reveal that the hydroxyl groups of polymer residues ...