Fabrication of BP nanosheets. (a) Schematic demonstration of the exfoliation of BP nanosheets using NaOH–NMP solvent. (b) Photographs of BP nanosheets dispersed in NMP and water. The dispersion solutions are: (1) pure water, (2) NMP-exfoliated phosphorene in NMP, (3) NMP-exfoliated phosphorene in water, (4) basic NMP-exfoliated phosphorene in NMP, and (5) basic NMP-exfoliated phosphorene in water. (c) TEM and (d) hydrodynamic sizes of the obtained BP nanosheets. Reproduced with permission.163 Copyright 2015, John Wiley and Sons. (e) The exfoliation of BP nanosheets using water as the solvent. Morphology characterization of BP nanosheets by (f) TEM, (g) AFM, and (h) corresponding height analysis. Reproduced with permission.141 Copyright 2015, American Chemical Society. (i) Schematic of green exfoliation of bulk BP into BP nanosheets using ionic liquids as the solvent. (j) Photograph of BP nanosheets dispersed in different ILs after centrifugation at 4000 rpm. (k) Photograph of the BP nanosheets dispersed in [BMIM][TfO] and [HOEMIM][TfO] (left) and the Tyndall effect of diluted BP nanosheets dispersions (right). (l) AFM image of the obtained BP nanosheets and the height analysis from the tested results. Reproduced with permission.73 Copyright 2015, American Chemical Society.