High-Yield Synthesis of Boron Nitride Nanosheets with Strong Ultraviolet Cathodoluminescence Emission

Abstract

Bulk quantities of hexagonal boron nitride (h-BN) nanosheets have been synthesized via a simple template- and catalyst-free chemical vapor deposition process at 1100−1300 °C. Adjusting the synthesis and chemical reaction parameters, the thickness of the BN nanosheets can be tuned in a range of 25−50 nm. Fourier transform infrared spectra and electron energy loss spectra reveal the typical nature of sp2-hybridization for the BN nanosheets. It shows an onset oxidation temperature of 850 °C for BN nanosheets compared with only about 400 °C for that of carbon nanotubes under the same conditions. It reveals a strong and narrow cathodoluminescence emission in the ultraviolet range from the h-BN nanosheets, displaying strong ultraviolet lasing behavior. The fact that this luminescence response would be rather insensitive to size makes the BN nanosheets ideal candidates for lasing optical devices in the UV regime. The h-BN nanosheets are also better candidates for composite materials in high-temperature and hazardous environments.

Simple synthesis of mesoporous boron nitride with strong cathodoluminescence emission

“…The broad emission peaks around 364 and 522 nm in the spectrum correspond to the energy of 3.41 and 2.38 eV, respectively. It is obvious that the emissions are greatly different from those resulted from pure h-BN single crystal with perfect crystallinity (215 nm) [27,28], but are similar to those from BN nanosheets (3.79-3.96 eV) [29], and BN nanotubes (3.0-4.2 eV) [31,32]. Comparing with the emission of pure h-BN single crystal, the shift of emission could be attributed to the significant difference in crystallinity, of course, other factors such as impurities, defects, or B and N vacancies are also inevitable [31,38].…”

“…Cathodoluminescence (CL) spectroscopy is an effective method to measure the optical property of BN with various morphologies. The spectra of BN nanosheets were reported to be between 3.79 and 3.96 eV owing to deep-level emissions associated with defect-related centers [29]. The CL spectra of BN nanoribbons are centered at 5.33 eV [30].…”

Facile synthesis of hexagonal boron nitride nanoplates via molten-salt-mediated magnesiothermic reduction

“…A variety of methodologies/techniques have been used to prepare h-BN powders with different sizes and purities, such as gas-solid or solid state reaction routes [12,13], carbothermic reduction and nitridation [14], chemical vapor deposition [15][16], autoclave route [17][18], and self-propagation high-temperature synthesis methods [19][20][21][22]. Amongst these methods, studies showed that the yield and crystallization of 4 as-prepared h-BN were promoted by adding alkali metal carbonate or alkaline earth oxides at a low content.…”

Highly thermally conductive and electrically insulating polymer nanocomposites with boron nitride nanosheet/ionic liquid complexes

“…For use in various applications, BNNS has attracted increasing interest because it has extremely high thermal conductivity (TC, 300-2000 W m À1 K À1 ), 2-4 high electrical insulation, 2,3 good mechanical properties, 2,3,5 high heat resistance, 1,3,6 high chemical resistance, 1,3,6 and whiteness. Especially, the nanosheets' high TC and electrically insulating properties are extremely attractive for fabricating electrically insulating materials with high heat transfer properties.…”