The Role of Water in the Preparation and Stabilization of High‐Quality Phosphorene Flakes

<b>The stability of phosphorene</b> is shown to be degraded by water. However, the presence of a small amount of water allows the synthesis of high-quality material in liquid exfoliation of black phosphorus using dimethylsulfoxide as solvent. A phosphorus/water molar ratio between 1.5 and 14 maximizes the quality of the phosphorene flakes and their stability.