Boron Nitride Nanosheets: Thickness‐Related Properties and Applications

Abstract Owing to its exceptional properties and wide‐ranging potential applications from aerospace to medicine, hexagonal boron nitride (h‐BN) has garnered considerable attention over the past decades. Boron nitride nanosheets (BNNSs), atomically thin h‐BN, not only inherit most of the outstanding properties of h‐BN but also exhibit superior characteristics compared to their bulk counterpart due to their reduced thickness, such as special adsorption behaviors and enhanced thermal conductivity. Furthermore, BNNSs display distinct thickness‐dependent properties from graphene and other 2D materials, such as unique mechanical response under indentation. This feature article provides an overview of the thickness‐related special properties of BNNSs, primarily derived from mechanically exfoliated h‐BN single crystals. These properties span various domains, including Raman signatures, molecule adsorption‐induced conformational changes, mechanical properties, thermal conductivity, and thermal expansion coefficients. Moreover, the feature article explores the underlying mechanisms governing these atomic‐scale thickness effects. Leveraging their unique properties, the feature article investigates diverse applications of BNNSs, encompassing surface‐enhanced Raman spectroscopy, metal‐enhanced fluorescence, and isotropic thermal management.