Facile microwave approach to controllable boron nitride quantum dots

Boron nitride quantum dots (BNQDs), as promising metal-free quantum dots with unique photoelectric properties, have been controllably fabricated by a facile and high-efficiency microwave irradiation technique in this work. Though a number of attempts have been reported so far, it remains challenging to explore an effective approach to synthesize high-quality BNQDs with uniform size, well dispersion and high quantum yield (QY). Microwave irradiation strategy is identified as an advanced and beneficial method not only for high-efficiency energy inputting but also time-saving in comparison with the reported solvothermal process. Encouragingly, the particle size and QY of BNQDs can be well controlled by adjusting microwave reaction temperature as well as duration time. The average diameter of the as-prepared blue luminescent BNQDs ranges from 1.98 to 7.05 nm with QY up to 23.44%. Furthermore, attributed to the unique nanostructure, quantum confinement effect, and high dielectric loss, the as-prepared BNQDs exhibits an optimal reflection loss of −19.6 dB at 8.9 GHz with a broad effective absorption bandwidth of 5.02 GHz in the frequency range of 2–18 GHz, demonstrating as potential microwave absorption material in electromagnetic interference field.