Freestanding non-covalent thin films of the propeller-shaped polycyclic aromatic hydrocarbon decacyclene.

Molecularly thin, nanoporous thin films are of paramount importance in material sciences. Their use in a wide range of applications requires control over their chemical functionalities, which is difficult to achieve using current production methods. Here, the small polycyclic aromatic hydrocarbon decacyclene is used to form molecular thin films, without requiring covalent crosslinking of any kind.

Power generation by reverse electrodialysis in a single-layer nanoporous membrane made from core-rim polycyclic aromatic hydrocarbons.

Nanoporous graphene and related atomically thin layered materials are promising candidates in reverse electrodialysis research owing to their remarkable ionic conductivity and high permselectivity. The synthesis of atomically thin nanoporous membranes with a narrow pore size distribution, however, remains challenging. Here, we report the fabrication of nanoporous carbon membranes via the thermal crosslinking of core-rim structured monomers, that is, polycyclic aromatic hydrocarbons.

Liquids relax and unify strain in graphene.

Solid substrates often induce non-uniform strain and doping in graphene monolayer, therefore altering the intrinsic properties of graphene, reducing its charge carrier mobilities and, consequently, the overall electrical performance. Here, we exploit confocal Raman spectroscopy to study graphene directly free-floating on the surface of water, and show that liquid supports relief the preexisting strain, have negligible doping effect and restore the uniformity of the properties throughout the graphene sheet. Such an effect originates from the structural adaptability and flexibility, lesser contamination and weaker intermolecular bonding of liquids compared to solid supports, independently of the chemical nature of the liquid.

Selective ion sieving through arrays of sub-nanometer nanopores in chemically tunable 2D carbon membranes.

Two-dimensional (2D) membranes featuring arrays of sub-nanometer pores have applications in purification, solvent separation and water desalination. Compared to channels in bulk membranes, 2D nanopores have lower resistance to transmembrane transport, leading to faster passage of ions. However, the formation of nanopores in 2D membranes requires expensive post-treatment using plasma or ion bombardment.

Contact angle measurement of free-standing square-millimeter single-layer graphene.

Square millimeters of free-standing graphene do not exist per se because of thermal fluctuations in two-dimensional crystals and their tendency to collapse during the detachment from the substrate. Here we form millimeter-scale freely suspended graphene by injecting an air bubble underneath a graphene monolayer floating at the water-air interface, which allowed us to measure the contact angle on fully free-standing non-contaminated graphene. A captive bubble measurement shows that free-standing clean graphene is hydrophilic with a contact angle of 42° ± 3°.

Electrophilic radical coupling at the edge of graphene.

We report the selective functionalization of an edge of graphene via the electrografting of 4-nitrobenzene diazonium tetrafluoroborate. The edge - a single line of carbon atoms - forms during the process of cutting a graphene monolayer with an atomically sharp microtome knife. Embedded in a polymeric matrix, the just cut bare graphene edge efficiently transfers electrons to a ferricyanide probe in solution.

Quantum and electrochemical interplays in hydrogenated graphene.

The design of electrochemically gated graphene field-effect transistors for detecting charged species in real time, greatly depends on our ability to understand and maintain a low level of electrochemical current. Here, we exploit the interplay between the electrical in-plane transport and the electrochemical activity of graphene. We found that the addition of one H-sp defect per hundred thousand carbon atoms reduces the electron transfer rate of the graphene basal plane by more than five times while preserving its excellent carrier mobility.

Spatiotemporal Control of Doxorubicin Delivery from "Stealth-Like" Prodrug Micelles.

In the treatment of cancer, targeting of anticancer drugs to the tumor microenvironment is highly desirable. Not only does this imply accurate tumor targeting but also minimal drug release en route to the tumor and maximal drug release once there. Here we describe high-loading, "stealth-like" doxorubicin micelles as a pro-drug delivery system, which upon light activation, leads to burst-like doxorbicin release.

Graphene-stabilized lipid monolayer heterostructures: a novel biomembrane superstructure.

Chemically defined and electronically benign interfaces are attractive substrates for graphene and other two-dimensional materials. Here, we introduce lipid monolayers as an alternative, structurally ordered, and chemically versatile support for graphene. Deposition of graphene on the lipids resulted in a more ordered monolayer than regions without graphene.

Chemistry at the Edge of Graphene.

The selective functionalization of graphene edges is driven by the chemical reactivity of its carbon atoms. The chemical reactivity of an edge, as an interruption of the honeycomb lattice of graphene, differs from the relative inertness of the basal plane. In fact, the unsaturation of the pz orbitals and the break of the π conjugation on an edge increase the energy of the electrons at the edge sites, leading to specific chemical reactivity and electronic properties.

Single molecule detection with graphene and other two-dimensional materials: nanopores and beyond.

Graphene and other two dimensional (2D) materials are currently integrated into nanoscaled devices that may - one day - sequence genomes. The challenge to solve is conceptually straightforward: cut a sheet out of a 2D material and use the edge of the sheet to scan an unfolded biomolecule from head to tail. As the scan proceeds - and because 2D materials are atomically thin - the information provided by the edge might be used to identify different segments - ideally single nucleotides - in the biomolecular strand.