Gas-Phase Nitrogen Doping of Monolithic TiO Nanoparticle-Based Aerogels for Efficient Visible Light-Driven Photocatalytic H Production.

The development of visible light-active photocatalysts is essential for increasing the conversion efficiency of solar energy into hydrogen (H). Here, we present a facile method for nitrogen doping of monolithic titanium dioxide (TiO) nanoparticle-based aerogels to activate them for visible light. Plasma-enhanced chemical vapor deposition at low temperature enables efficient incorporation of nitrogen into preformed TiO aerogels without compromising their advantageous intrinsic characteristics such as large surface area, extensive porosity, and nanoscale properties of the semiconducting building blocks.

Multifunctional wafer-scale graphene membranes for fast ultrafiltration and high permeation gas separation.

Reliable and large-scale manufacturing routes for perforated graphene membranes in separation and filtration remain challenging. We introduce two manufacturing pathways for the fabrication of highly porous, perforated graphene membranes with sub-100-nm pores, suitable for ultrafiltration and as a two-dimensional (2D) scaffold for synthesizing ultrathin, gas-selective polymers. The two complementary processes-bottom up and top down-enable perforated graphene membranes with desired layer number and allow ultrafiltration applications with liquid permeances up to 5.

Annealing and polycrystallinity effects on the thermal conductivity of supported CVD graphene monolayers.

The thermal transport properties of graphene are strongly influenced by its contact environment and the strength of such interactions can be used to tailor these properties. Here we find that annealing suppresses the basal plane thermal conductivity (κ) of graphene supported on silicon dioxide, due to the increased conformity of graphene to the nanoscale asperities of the substrate after annealing. Intriguingly, increasing the polycrystallinity of graphene, grown by chemical vapor deposition on copper, increases the severity of this suppression after annealing, revealing the role of grain boundaries and associated defects in aiding phonon scattering by the substrate.

Smart Reinvention of the Contact Lens with Graphene.

With potential benefits to the 71 million contact lens users worldwide, contact lenses are being reinvented in the form of smart wearable electronics. In this issue of ACS Nano, Lee et al. report on the fascinating functions of a graphene-based smart contact lens that is able to protect eyes from electromagnetic waves and dehydration.

Ion beam profiling from the interaction with a freestanding 2D layer.

Recent years have seen a great potential of the focused ion beam (FIB) technology for the nanometer-scale patterning of a freestanding two-dimensional (2D) layer. Experimentally determined sputtering yields of the perforation process can be quantitatively explained using the binary collision theory. The main peculiarity of the interaction between the ion beams and the suspended 2D material lies in the absence of collision cascades, featured by no interaction volume.

Reduced Water Vapor Transmission Rate of Graphene Gas Barrier Films for Flexible Organic Field-Effect Transistors.

Preventing reactive gas species such as oxygen or water is important to ensure the stability and durability of organic electronics. Although inorganic materials have been predominantly employed as the protective layers, their poor mechanical property has hindered the practical application to flexible electronics. The densely packed hexagonal lattice of carbon atoms in graphene does not allow the transmission of small gas molecules.

Ultraclean patterned transfer of single-layer graphene by recyclable pressure sensitive adhesive films.

We report an ultraclean, cost-effective, and easily scalable method of transferring and patterning large-area graphene using pressure sensitive adhesive films (PSAFs) at room temperature. This simple transfer is enabled by the difference in wettability and adhesion energy of graphene with respect to PSAF and a target substrate. The PSAF-transferred graphene is found to be free from residues and shows excellent charge carrier mobility as high as ∼17,700 cm(2)/V·s with less doping compared to the graphene transferred by thermal release tape (TRT) or poly(methyl methacrylate) (PMMA) as well as good uniformity over large areas.

A highly conducting graphene film with dual-side molecular n-doping.

Doping is an efficient way to engineer the conductivity and the work function of graphene, which is, however, limited to wet-chemical doping or metal deposition particularly for n-doping, Here, we report a simple method of modulating the electrical conductivity of graphene by dual-side molecular n-doping with diethylenetriamine (DETA) on the top and amine-functionalized self-assembled monolayers (SAMs) at the bottom. The resulting charge carrier density of graphene is as high as -1.7 × 10(13) cm(-2), and the sheet resistance is as low as ∼86 ± 39 Ω sq(-1), which is believed to be the lowest sheet resistance of monolayer graphene reported so far.

Optical probing of the electronic interaction between graphene and hexagonal boron nitride.

Even weak van der Waals (vdW) adhesion between two-dimensional solids may perturb their various materials properties owing to their low dimensionality. Although the electronic structure of graphene has been predicted to be modified by the vdW interaction with other materials, its optical characterization has not been successful. In this report, we demonstrate that Raman spectroscopy can be utilized to detect a few percent decrease in the Fermi velocity (v(F)) of graphene caused by the vdW interaction with underlying hexagonal boron nitride (hBN).