NRC Postdoctoral Scholar, US Naval Research Laboratory, Washington, District of Columbia, 20375, United States of America.
Nanotechnology. 2017 Apr 18;28(15):155601. doi: 10.1088/1361-6528/aa62f6. Epub 2017 Feb 24.
Exfoliation of two-dimensional phosphorene from bulk black phosphorous through chemical means is demonstrated where the solvent system of choice (choline chloride urea diluted with ethanol) has the ability to successfully exfoliate large-area multi-layer phosphorene sheets and further protect the flakes from ambient degradation. The intercalant solvent molecules, aided by low-powered sonication, diffuse between the layers of the bulk black phosphorus, allowing for the exfoliation of the multi-layer phosphorene through breaking of the interlayer van der Waals bonds. Through viscosity tuning, the optimal parameters (1:1 ratio between the intercalant and the diluting solvent) at which the exfoliation takes place is determined. Our exfoliation technique is shown to produce multi-layer phosphorene flakes with surface areas greater than 3 μm (a factor of three larger than what has previously been reported for a similar exfoliation method) while limiting exposure to the ambient environment, thereby protecting the flakes from degradation. Characterization techniques such as optical microscopy, Raman spectroscopy, ultraviolet-visible spectroscopy, and (scanning) transmission electron microscopy are used to investigate the quality, quantity, and thickness of the exfoliated flakes.
通过化学方法从块状黑磷中剥离二维磷烯，其中选择的溶剂体系（氯化胆碱-尿素稀释的乙醇）具有成功剥离大面积多层磷烯片并进一步保护薄片免受环境降解的能力。插层溶剂分子在低功率超声的辅助下在块体黑磷的层间扩散，通过打破层间范德华键来实现多层磷烯的剥离。通过粘度调谐，确定了发生剥离的最佳参数（插层剂与稀释溶剂的 1:1 比例）。我们的剥离技术显示，所产生的多层磷烯薄片的表面积大于 3μm（比以前报道的类似剥离方法大了三倍），同时限制了与环境的接触，从而保护了薄片免受降解。光学显微镜、拉曼光谱、紫外-可见光谱和（扫描）透射电子显微镜等表征技术用于研究剥离薄片的质量、数量和厚度。
