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Electrowetting is a simple way to induce the spreading and retraction of electrolyte droplets. This method is widely used in “device” applications, where a dielectric layer is applied between the...

A green and facile molten-salt (MS) route for the scalable synthesis of free-standing, long-range oriented and corrugated graphene-like sheets from a copper phthalocyanine (CuPc) precursor is reported. Their unique arrangement and transformation behavior in molten potassium chloride (KCl) play a key role in promoting the successful synthesis of the anisotropic nanostrucure.

With the profuse amount of two-dimensional (2D) materials discovered and the improvements in their synthesis and handling, the field of 2D heterostructures has gained increased interest in recent years. Such heterostructures not only overcome the inherent limitations of each of the materials, but also allow the realization of novel properties by their proper combination. The physical and mechanical properties of graphene mean it has a prominent place in the area of 2D heterostructures. In this review, we will discuss the evolution and current state in the synthesis and applications of graphene-based 2D heterostructures. In addition to stacked and in-plane heterostructures with other 2D materials and their potential applications, we will also cover heterostructures realized with lower dimensionality materials, along with intercalation in few-layer graphene as a special case of a heterostructure. Finally, graphene heterostructures produced using liquid phase exfoliation techniques and their applications to energy storage will be reviewed.

We demonstrate the controlled tuning of the electronic band structure of large-arrays of graphene nanoribbons (GNRs) by chemical functionalization. The GNR arrays are synthesized by substrate-controlled metal-assisted etching of graphene in H2 at high temperature, and functionalized with different molecules. From Raman spectroscopy and carrier transport measurements, we found that 4-nitrobenzenediazonium (4-NBD) and diethylene triamine (DETA) molecules can tune the doping level of the GNR arrays to p- and n-type, respectively. In both cases, the doping effects induced in the GNRs were found to be higher than for a pristine graphene sheet, due to the presence of a large quantity of edges. Effects of chemical doping on the Raman spectrum of sp(2) carbon materials are also discussed. Our findings offer an effective way to control the electronic structure of GNRs by chemical functionalization, and are expected to facilitate the production of nanoribbon-based p-n junctions for future implementation into electronic circuits.

Chemical functionalisation is a promising method to tune the electronic structure of graphene, and the two-dimensional structure of graphene enables access to both of its faces for various types of functionalisation. Here, we present the effect of covalent functionalisation on the Raman spectrum in terms of monofacial (one-sided) and bifacial (two-sided) functionalisation using both monolayer and bilayer graphene. Asymmetrical or ‘Janus’ functionalisation is found to provide significantly increased levels of doping compared to other schemes allowing for control over graphene's electronic structure as well as control over surface functionality.

Vertically aligned single-walled carbon nanotube arrays have shown great promise for applications as electrochemical devices due to their high conductivity and large electrode surface area. There has also been research showing that they can be applied to transparent photovoltaic devices. In this work we synthesised vertically aligned single-walled carbon nanotube arrays and further modified these with PAMAM-type dendrons. These dendrons have previously been shown to increase the photovoltaic performance of the nanotube arrays. The dendrons were then further modified using a ruthenium based dye, commonly known as N3. The presence of this dye on increasing generations of dendron was investigated using electrochemistry to determine the surface concentration and electron transfer co-efficient, with the dye modified generation 1.5 dendron providing the highest surface N3 concentration with 1.98 × 1013 molecules cm−2. Additionally, photovoltaic testing was performed on each generation and the optimal dye modification was found to provide a 35% increase in power output after the dendron functionalisation whilst still using very little material and remaining transparent.