The combination of properties of boron nitride nanotubes (BNNTs) makes them desirable building blocks for the development of functional macroscopic materials with unprecedented electronic and mechanical features. However, these properties have not been fully exploited because their chemical inertness hampers their processing. One solution is to covalently functionalize the BNNTs to assist in their individualization, dispersion, and processing. Here, we show that dodecyl chains can be covalently attached to BNNTs through the Billups-Birch reaction using lithium and 1-bromododecane as reagents. By combining thermogravimetric and spectroscopic analyses, we were able to verify the presence of the alkyl chains that chemically graft to the outermost wall of the nanotubes, as well as unveil the sp2 to sp3 rehybridization. The hydrophobic addends change the dispersibility and individualization of BNNTs in various organic solvents, which we envision will allow the manufacturing of sophisticated materials such as polymer and ceramic nanocomposites with enhanced strength and thermal stability. Furthermore, because of the inherent thermal stability of BNNTs, the alkyl moieties can be easily removed at high temperatures in air without oxidizing the nanotubes. This chemical functionalization provides a straightforward way to tune the properties of BNNTs, which until now has proven to be a formidable undertaking.

Herein we introduce af acile,s olution-phase protocol to modify the Lewis basic surface of few-layer black phosphorus (bP) and demonstrate its effectiveness at providing ambient stability and tuning of electronic properties.Commercially available group 13 Lewis acids that range in electrophilicity,steric bulk, and Pearson hard/soft-ness are evaluated. The nature of the interaction between the Lewis acids and the bP lattice is investigated using arange of microscopic (optical, atomic force,s canning electron) and spectroscopic (energy dispersive,X-ray photoelectron) methods.A la nd Ga halides are most effective at preventing ambient degradation of bP (> 84 hf or AlBr 3), and the resulting field-effect transistors show excellent IV characteristics,p hotocurrent, and current stability,a nd are significantly p-doped. This protocol, chemically matched to bP and compatible with device fabrication, opens ap ath for deterministic and persistent tuning of the electronic properties in bP.

Surface functionalization of two-dimensional crystals is a key path to tuning their intrinsic physical and chemical properties. However, synthetic protocols and experimental strategies to directly probe chemical bonding in modified surfaces are scarce. Introduced herein is a mild, surfacespecific protocol for the surface functionalization of few-layer black phosphorus nanosheets using a family of photolytically generated nitrenes (RN) from the corresponding azides. By embedding spectroscopic tags in the organic backbone, a multitude of characterization techniques are employed to investigate in detail the chemical structure of the modified nanosheets, including vibrational, X-ray photoelectron, solid state 31 P NMR, and UV-vis spectroscopy. To directly probe the functional groups introduced on the surface, R fragments were selected such that in conjunction with vibrational spectroscopy, 15 N-labeling experiments, and DFT methods, diagnostic P = N vibrational modes indicative of iminophosphorane units on the nanosheet surface could be conclusively identified.

The functionalization of nanomaterials has long been studied as a way to manipulate and tailor their properties to a desired application. Of the various methods available, the Billups–Birch reduction has become an important and widely used reaction for the functionalization of carbon nanotubes (CNTs) and, more recently, boron nitride nanotubes. However, an easily overlooked source of error when using highly reductive conditions is the utilization of poly(tetrafluoroethylene) (PTFE) stir bars. In this work, we studied the effects of using this kind of stir bar versus using a glass stir bar by measuring the resulting degree of functionalization with 1-bromododecane. Thermogravimetric analysis studies alone could deceive one into thinking that reactions stirred with PTFE stir bars are highly functionalized; however, the utilization of spectroscopic techniques, such as Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, tells otherwise. Furthermore, in the case of CNTs, we determined that using Raman spectroscopy alone for analysis is not sufficient to demonstrate successful chemical modification.

Hexagonal boron nitride (h-BN), also known as white graphene, presents an unparalleled combination of properties, including superior mechanical strength, good thermal conductivity, a wide band gap, and chemical and thermal inertness. However, because of its aversion to chemical modification, its applications have not progressed as much as those of carbon nanomaterials. In this manuscript, we show the functionalization of hexagonal boron nitride using alkyl halides in strongly reducing conditions (Billups–Birch conditions). The tunability of the Billups–Birch reaction is demonstrated by alkylating hexagonal boron nitride with 1-bromododecane and varying equivalents of Li to BN. We found that using a 1:20 BN/Li ratio yields the highest chemical modification, as demonstrated using thermogravimetric analysis and Fourier transform infrared spectroscopy, and supported by X-ray photoelectron spectroscopy. Imaging of the functionalized h-BN (fh-BN) revealed that its sheets exfoliate better in isopropanol than pristine h-BN, which displays highly stacked nanostructures. Moreover, bearing alkyl chains confers the nanosheets with improved dispersibility in nonpolar solvents, such as dodecane, and allows the formation of hydrophobic films.