“Chemical Blowing” of Thin‐Walled Bubbles: High‐Throughput Fabrication of Large‐Area, Few‐Layered BN and Cx‐BN Nanosheets

Two-dimensional (2D) crystals have displayed unique potentials in energy, catalysis, superconductivity, and electronics fi elds because of their low dimensions and special edge structures. [ 1 , 2 ] Among the 2D crystals, sp 2 -hybridized graphene and its sister, monolayered hexagonal boron nitride ( h -BN, so-called “white graphene”), may be equally attractive for fundamental physics and diverse functionalities. BN atomic sheets conventionally show excellent deep UV luminescence [ 3 , 4 ] and superb lubrication. [ 5 ] Their composites with polymers or bioceramics exhibit extraordinary thermoconductive and mechanical properties. [ 6 , 7 ] They can also serve as a dielectric gate layer, [ 8 ] as well as an edge-tailored bandgap-tunable semiconductor, [ 9 ] and as a substrate able to enhance the carrier mobility [ 10 ] and to open the bandgap in graphene. [ 11 , 12 ] They are the perfect “sidekick” of graphene in next-generation electronics. Moreover, merging “black” (i.e., carbon) and “white” (i.e., BN) graphenes, B–C–N atomic sheets may be envisioned as an important congener for fl at electronics, providing a smart approach to semiconductivity. [ 13 ] In fact, the potentially tunable bandgaps of the B–C–N system will enable its outstanding functional fl exibility in luminescence and electronics. [ 14 ]