Graphene–organic composites for electronics: optical and electronic interactions in vacuum, liquids and thin solid films

Abstract

Graphene exhibits exceptional mechanical, optical and electrical properties that are unfortunately accompanied by poor processability and tunability of its properties. The controlled interaction of graphene with tailor-made organic semiconductors (OSs) can offer a solution to solve these two problems simultaneously. The use of wellchosen organic semiconducting molecules interacting with graphene enables optimal control over the molecular self-assembly process forming low-dimensional graphene-organic architectures. Moreover, OSs allow modulation of numerous physical and chemical properties of graphene, including controlled electrical doping, ultimately making it possible to boost the performance of conventional organic electronic devices.Significantly, the interaction of organic molecules with graphene is strong not only at short distances but it is relevant also at longer distances, up to 30 nm. This feature article reviews some of the most enlightening results in the field, giving an overview of the interaction between graphene and organic molecules, starting from the simplest systems at the molecular scale, single molecules on single layer graphene in UHV, up to mesoscopic, more complex systems i.e., thick interpenetrated layers of graphene-organic composites embedded in working electronic or photovoltaic devices.

Femtosecond electrons probing currents and atomic structure in nanomaterials

“…Using a nanotip as miniaturized electron gun for fsLEED allows to reduce the electron propagation length to the 100-mm range and to minimize temporal broadening to the 100-fs range. Combining the high surface sensitivity of low-energy electrons with femtosecond time resolution, fsLEED will reveal real-time information on structural dynamics and energy transfer processes in monolayer 2D materials and inorganic 36 as well as organic 37 composite heterostructures thereof.…”

Graphene flakes at the SiO2/organic-semiconductor interface for high-mobility field-effect transistors

“…One of the most promising approaches includes graphene/OS blends as active layers in organic devices. These novel composite systems, combine high charge carrier mobility of graphene and functionality of polymers such as energy gap, light sensitivity, temperature stability [1]. Potential application of these blends includes ink-jet printed multifunctional electronic circuits, such as organic solar cells [2], organic memory devices [3], or organic thin film transistors (OTFTs) [4e11].…”

Supramolecular Approaches to Graphene: From Self‐Assembly to Molecule‐Assisted Liquid‐Phase Exfoliation

“…[41,42] While defect-free sheets can be obtained by exploiting the micromechanical cleavage, [43] approaches such as ballmilling [44][45][46][47][48][49] can trigger the formation of defects in graphene. Amongst the top-down approaches, liquid-phase exfoliation (LPE), which can be further sub-divided into different methods, i.e., solvothermal-assisted LPE (SALPE), [50,51] electrochemical LPE (ELPE), [52][53][54][55][56] high-shear mixing (HSM), [57,58] ultrasoundinduced LPE (UILPE), [59][60][61][62][63][64][65] and the use of superacids, [66] represents an extremely versatile approach which can be carried out in a variety of environments. While bottom-up methods, and in particular CVD, can yield large size, LPE gives limited sheet sizes.…”