Controllable preparation of boron nitride quantum dots with small size and strong blue photoluminescence

As a new type of quantum dots (QDs), boron nitride QDs (BNQDs), show promising potentials in disease diagnosis, fluorescence imaging and bio-sensing due to its good biocompatibility, low cytotoxicity and excellent photoluminescence performance. However, there are still challenges in preparing BNQDs with uniform and small size. In this paper, the BNQDs with uniform and small size have been prepared through a hydrothermal process with the exfoliated hexagonal boron nitride nanosheets (h-BNNSs) as precursor. The as-prepared BNQDs were characterized by transmission electron microscope (TEM), high-resolution TEM, fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV-vis and photoluminescence spectra (PL) for morphology, surface functional groups, element composition and optical properties. The as-prepared BNQDs have uniform particle size distribution with an average lateral size of 1.65 nm, and a PL quantum yield of 2.49 %. In addition, the as-prepared BNQDs exhibit strong blue fluorescence under UV-vis (365 nm) irradiation and nanosecond luminescent decay. Furthermore, the effect of preparation parameters on the fluorescence performance of BNQDs was investigated which provides an optimal condition for the preparation of BNQDs with excellent fluorescence performance. Together with other advantages, such as excellent physical/chemical properties, good biocom-patibility and low cytotoxicity, the as-prepared BNQDs have great potentials in medical diagnosis, biosensing, photoelectric devices and other fields in the future.

Automated summary

In this study, uniform and small-sized BNQDs were successfully prepared through a hydrothermal process using exfoliated h-BNNSs as precursor. Various characterization techniques were employed to study the morphology, surface functional groups, element composition, and optical properties of the BNQDs. The fluorescence performance of BNQDs was found to be influenced by preparation parameters, providing optimal conditions for the preparation of BNQDs with excellent fluorescence performance in the future.