Oxidizing Hexagonal Boron Nitride into Fluorescent Structures by Photodissociated Directional Oxygen Radical.

Modifying the wide band gap semiconductor hexagonal boron nitride (hBN) can bring new chances in photonics. By virtue of the solvothermal/hydrothermal oxidation or functionalization, hBN can be converted into fluorescent nanodots. Until now, it has been a big challenge to drily oxidize hBN and turn it into bright fluorescent structures due to its superior chemical stability. Here, we report the oxidation of multilayer hBN into fluorescent structures by ultraviolet (UV, λ = 172 nm) photodissociated directional oxygen radical [O( 3 P)] in a gradient magnetic field. The paramagnetic O( 3 P), produced in a low-pressure O 2 atmosphere, drifts toward hBN and then converts it into boron nitride oxide (BNO) micro/nanometer structures constituted by BO, BO 2 , and O-doped hBN. For a properly oxidized BNO substance, bright and photostable wide-band photoluminescence is realized with nanosecond-scaled lifetimes under the excitation of UV and visible lights.