Functionalization of hexagonal boron nitride nanosheets and their copolymerized solid glasses

Abstract

Hexagonal boron nitride nanosheets (h-BNNSs) with unique properties, including wide band gap, excellent thermal conductivity and thermal stability, are among the most promising 2D inorganic nanomaterials in recent years. Functionalization of h-BNNSs is necessary to prevent them from strong tendency to agglomeration and to improve their dispersity and interfacial properties in solvents and polymer composites. In this work, amino and silane functionalized h-BNNSs were obtained, respectively. The chemical-bonding amino and silane functionalization of h-BNNSs were verified by FTIR, XPS and TG-MS analyses. The functionalized h-BNNSs show higher concentration, improved compatibility and dispersity in solvents and gel matrices after doping them into organically-modified silicate gel glasses using a sol-gel method. The functionalized h-BNNSs have broadband absorption and their doped glasses show high transmittances in the visible and near-infrared regions. The nonlinear optical properties of the functionalized h-BNNSs and their doped glasses were measured using Nd:YAG laser system and the doped glasses show broadband optical limiting responses at 532–1570 nm with the lowest onset threshold of 9 mJ cm−2. The optical limiting mechanisms investigated through Z-scan technique were nonlinear absorption. This work indicates that the functionalized h-BNNSs and their doped glasses are promising candidates for nonlinear optical, optical limiting and other optoelectronic materials and devices.