Herein, we have developed a systematic study on the oxidation and passivation of mechanically exfoliated black phosphorus (BP). We analyzed the strong anisotropic behavior of BP by scanning Raman microscopy providing an accurate method for monitoring the oxidation of BP via statistical Raman spectroscopy. Furthermore, different factors influencing the environmental instability of the BP, i.e., thickness, lateral dimensions or visible light illumination, have been investigated in detail. Finally, we discovered that the degradation of few-layer BP flakes of <10 nm can be suppressed for months by using ionic liquids, paving the way for the development of BP-based technologies.

Black phosphorus (BP) was functionalized with organic moieties on the basis of liquid exfoliation. The treatment of BP with electron-withdrawing 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) led to electron transfer from BP to the organic dopant. On the other hand, the noncovalent interaction of BP with a perylene diimide was mainly due to van der Waals interactions but also led to considerable stabilization of the BP flakes against oxygen degradation.

Herein, we report on a significant discovery, namely, the quantitative discharging of reduced graphite forms, such as graphite intercalation compounds, graphenide dispersions and graphenides deposited on surfaces with the simple solvent benzonitrile. Because of its comparatively low reduction potential, benzonitrile is reduced during this process to the radical anion, which exhibits a red colour and serves as a reporter molecule for the quantitative determination of negative charges on the carbon sheets. Moreover, this discovery reveals a very fundamental physical–chemical phenomenon, namely a quantitative solvent reduction induced and electrostatically driven mass transport of K+ ions from the graphite intercalation compounds into the liquid. The simple treatment of dispersed graphenides suspended on silica substrates with benzonitrile leads to the clean conversion to graphene. This unprecedented procedure represents a rather mild, scalable and inexpensive method for graphene production surpassing previous wet-chemical approaches.

We demonstrate random network single-walled carbon nanotube (SWNT) field-effect transistors (FETs) in bottom contact/top gate geometry with only five different semiconducting nanotube species that were selected by dispersion with poly(9,9-dioctylfluorene) in toluene. These FETs are highly ambipolar with balanced hole and electron mobilities and emit near-infrared light with narrow peak widths (<40 meV) and good efficiency. We spatially resolve the electroluminescence from the channel region during a gate voltage sweep and can thus trace charge transport paths through the SWNT thin film. A shift of emission intensity to large diameter nanotubes and gate-voltage-dependent photoluminescence quenching of the different nanotube species indicates excitation transfer within the network and preferential charge accumulation on small band gap nanotubes. Apart from applications as near-infrared emitters with selectable emission wavelengths and narrow line widths, these devices will help to understand and model charge transport in realistic carbon nanotube networks.

Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under http://dx.