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Fluorescent monolayer boron nitride based quantum dots, including boron nitride quantum dots and boron carbon oxynitride quantum dots, were successfully fabricated via a hydrothermal method by cutting the bulk material assisted by a basic solution. The boron nitride/boron carbon oxynitride quantum dots are water-soluble with uniform lateral sizes around 3.3 and 4.0 nm respectively. The application of the as-prepared quantum dots as promising bio-imaging probes was demonstrated through labeling HeLa cells with boron nitride/boron carbon oxynitride quantum dots, indicating single layered boron nitride/boron carbon oxynitride quantum dots could be further used in biological applications.

Graphene as a coating material that shows high impermeability as an excellent barrier in oxidation and corrosion protection has been reported to be less stable at elevated temperature. Sometimes the formed galvanic cell between the graphene and protective surface will even increase the corrosion speed. In comparison, boron nitride (BN), which shows the same impermeability with graphene, is believed to be a better coating material with its superior thermal and chemical inertness. In this study, an in situ synthesis of BN coatings, grown by boron ink, on both carbon and Cu for anti-oxidation and anti-corrosion purposes has been demonstrated. Thermogravimetric analysis and electrochemical analysis reveal that the BN coatings can effectively prevent the carbon from being oxidized at high temperature in air and adequately slow down the corrosion rate of Cu in sodium chloride solution, respectively. These results indicate that boron ink assisted in situ BN coating has high potential in the applications of oxidation and corrosion protection.

Layered boron nitrides (BNs) are usually viewed as excellent protective coatings and reinforcing materials due to their chemical inertness and high mechanical strength. However, the attention paid to their potential applications in gas sorption, especially in case of hydrogen, has obviously been insufficient. Herein, a novel BN material (i.e., porous microbelts), with the highest specific surface area ever reported for any BN system, up to 1488 m² g⁻¹, is obtained through one-step template-free reaction of a boron acid-melamine precursor with ammonia. Comprehensive high-resolution transmission electron microscopy, X-ray diffraction, and Raman characterizations all confirm that the obtained BN phase is partially disordered, shows an enlarged average spacing between adjacent (0002) layers (d₀₀₀₂ = 0.38 nm, compared to normal 0.33 nm for a bulk layered BN), and belongs to an intermediate state between hexagonal (h-BN) and amorphous (a-BN) phases. By changing the synthesis temperatures, the textures of obtained porous microbelts are adjustable. H₂ sorption evaluations demonstrate that the materials exhibit high and reversible H₂ uptake from 1.6 to 2.3 wt % at 77 K and at a relatively low pressure of 1 MPa.

We report on the basic physical quantities of boron nitride nanotubes (BNNTs), namely specific heat capacity and density, which have not been measured to date. A series of differential scanning calorimetry experiments were performed, and specific heat capacity was calculated for multi-walled BNNTs synthesized by chemical vapor deposition using boron and metal oxide as precursor. Very close specific heat capacity values were revealed for BNNTs and a BN powder of hexagonal (h-BN) phase. Densities of BNNTs were measured through density analyses of their epoxy composites. Our work is important as far as bulk properties of large amounts of BNNTs are crucial, for example, thermal property and density prediction for composite materials with BNNTs embedded.

We have carried out an isotope study on the band gap and radiative transition spectra of boron nitride nanotubes (BNNTs) using both experimental and theoretical approaches. The direct band gap of BNNTs was determined at 5.38 eV, independent of the nanotube size and isotope substitution, by cathodoluminescences (CL) spectra. At lower energies, several radiative transitions were observed, and an isotope effect was revealed. In particular, we confirmed that the rich CL spectra between 3.0 and 4.2 eV reflect a phonon-electron coupling mechanism, which is characterized by a radiative transition at 4.09 eV. The frequency red shift and peak broadening due to isotopic effect have been observed. Our Fourier transform infrared spectra and density functional theory calculations suggest that those radiative transitions in BNNTs could be generated by a replacement of some nitrogen atoms with oxygen.

We have used Raman spectroscopy to study the behavior of multi-walled boron nitride nanotubes and hexagonal boron nitride crystals under high pressure. While boron nitride nanotubes show an irreversible transformation at about 12 GPa, hexagonal boron nitride exhibits a reversible phase transition at 13 GPa. We also present molecular dynamics simulations which suggest that the irreversibility of the pressure-induced transformation in boron nitride nanotubes is due to the polar nature of the bonds between boron and nitrogen.

(Figure Presented) A self-organized film of boron nitride nanotube-polyaniline (BNNT-PANI) composite is fabricated by using a simple solution method. The BNNTs are fully coated with PANI as a result of strong interactions between these components (see picture). Mechanically tough, BNNTs may have potential as stabilizing additives to PANI or other polymers.

(Figure Presented) Playing with the band: Long alkyl chains are bound to boron nitride nanotubes (BNNTs) from the reaction of stearoyl chloride with amino groups on the BNNTs; the resulting functionalized BNNTs (see picture) are soluble in many organic solvents. Cathodoluminescence and UV/Vis absorption experiments indicate that the long alkyl chains may induce drastic changes in the band structure of BNNTs.

Large quantities of highly pure BN nanotubes have been synthesized within a wide temperature range through using a mixture of FeO, MgO and boron powder as the precursor. X-ray diffraction pattern indicated highly pure h-BN phase of our sample. The morphology and microstructure were investigated by scanning electron microscopy and transmission electron microscopy. The growth mechanism of BN nanotubes has been clarified to be a catalytic growth.

The oxidation process of boron nitride nanotubes was thoroughly investigated, and a slow oxidation characteristic was clearly revealed. Subsequently, the controllable oxidation process was utilized to break the sturdy structure of the boron nitride nanotubes to fabricate shortened nanotubes. The shortened boron nitride nanotubes were found to possess good solubility in water and many organic solvents. Further experiments demonstrated remarkably improved molecule-loading capacity of the shortened boron nitride nanotubes. These dispersible shortened boron nitride nanotubes might have the potential to be developed as effective delivery systems for various molecules, which may find applications in bio-related fields.

Closed-shell BO(2)(-) and BO(-) anions are proposed as high-efficiency luminescence centres in boron-nitrogen systems, which makes the anions localized and leads to a radiation transition.

Boron nitride nanotubes (BNNTs) were synthesized by a carbon-free chemical vapor deposition method using boron and metal oxide as reactants. Then SnO(2) nanoparticles were functionalized on them via a simple wet chemistry method. Detailed transmission electron microscopy (TEM) observations reveal that SnO(2) nanoparticles may cover the tube surface or be encapsulated in tube channels. The lattice distances of both BNNT and SnO(2) have been changed due to the strong interactions between them. The band gap energy of SnO(2) particles is found enlarged due to the size effect and interaction with BNNTs.

Peeling off the layers: Boron nitride nanotubes (BNNTs) can be successfully peeled upon heating in dimethyl sulfoxide solution. The peeled BN shells can be reassembled into nanotubes branching from BNNT trunks to form Y-junction BNNTs (see TEM images). (Figure Presented).

We report a hard X-ray photoelectron spectroscopy (HX-PES) investigation on valence band structure of Boron Nitrides (BN) having different morphologies, including nanosheets, nanotubes, and micro-sized particles. Very weak morphology/valence band structure dependence was observed. For each case, the B-N π-band overlapping with σ-band between 0 to −12.5 eV and the s-band below −15 eV were identified. No obvious morphology-induced band shifts and intensity variations were observed. First-principles calculations based on density functional theory were performed and the results were compared with the experimental data. This theoretical analysis well explains the weak morphology dependent valence band spectra of BN nanomaterials obtained during HX-PES measurements.

Boron nitride nanotubes (BNNTs) are excellent nanofillers to enhance the mechanical and thermal properties of polymer nanocomposites. Despite the rapid progress in the effective syntheses of BNNTs, the ease of processability and solubility are major roadblocks for their widespread applications. The present work reports for the first time: a facile and environment-friendly green approach for aqueous bioinspired functionalization of boron nitride nanotubes through the use of dopamine, a synthetic mimic of mussel adhesive proteins. This approach is based on the affinity of the amino group of dopamine molecules for the boron atoms in BNNTs and π–π interactions as well as van der Waals interactions between the BNNTs network and dopamine molecules. Functionalization of the boron nitride nanotubes was evidently found to be associated with the existing π–π bonding and van der Waals interactions at the BNNT surfaces, involving the aromatic core structures of the dopamine molecules based on various characterizations. The resultant functionalized BNNTs are highly dispersible in water and a number of solvents. Polymer nanocomposites were prepared using pristine and dopamine functionalized BNNTs as reinforcement in a poly(vinyl difluoroethylene) matrix and tested for the thermal and mechanical properties. The functionalized BNNT reinforced polymer nanocomposites exhibit superior properties as compared to nanocomposites based on pristine BNNTs. This comprehensive study indicates that dopamine functionalized BNNTs are promising materials for various applications and are expected to form the basis of a new class of chemically reactive nanostructures.

we describe synthesis, property investigations and composite applications of multi-walled boron nitride nanotubes.