Synthesis and Characterization of Boron Nitride Dots

Zero-dimensional (0D) boron nitride nanoparticles (BN dots) are biological and environmentally compatible for biomedical applications. There is growing interest in using BN dots for electronics and optoelectronics applications [1]. BN dots can be produced mainly in two ways: top-down or bottom-up method. Top-down methods shrink large materials to nanoscale quantum dots, such as the breaking of bulk hexagonal BN powders (h-BN) into 0D structures. In the bottom-up methods, B and N precursors are used for producing BN dots.

Recently, we demonstrated that BN dots can be chemically functionalized to form high-brightness fluorophores (HBFs) for biological detection [2]. For such an application, it is desired that all the BN dots are small and uniform in size. In this study, we compare two different top-down approaches to synthesizing uniform BN dots. Firstly, we combine ultrasonication and solvothermal treatment of bulk h-BN powders into BN dots. Secondly, we combine cryo-assisted liquid-phase exfoliation and ultrasonication. The yields and purity of BN dots in these two approaches are compared. We further examine their size distribution by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The optical properties of the products are also characterized by UV-Vis and fluorescent spectroscopy. The details of the synthesis approach and the properties of these BN dots will be discussed in the conference.