From amorphous red phosphorus to black phosphorus crystal: An optimization, controllable and highest yield synthesis process

Understanding the growth mechanism of large crystals and high-quality of black phosphorus (BP) is a fundamental challenge to further study its physical properties. The BP was prepared from amorphous red phosphorus (RP), by short-way chemical vapor transport (CVT) reaction using the addition of small quantities of copper, tin, and tin(IV) iodide as reaction promoters. The method used in this present work is currently developed by our research laboratory for preparation of BP. In fact, a series of experiments was designed to understand and optimize the preparation conditions (the catalyst's choice (Cu), temperature, time, dimensions of quartz tube …) of this surprisingly easy and effective method and to ensure a high BP conversion ratio (wt%) from RP with high purity, high crystallinity, and large size of orthorhombic BP (flakes size ∼ 1 cm), It’s the main goal of this work. The products recovered in the hot and cold zones of the tube are analyzed by X-ray diffraction (XRD) to give an idea of the role of mineralizers (Cu,Sn, and SnI4) allowing the synthesis of BP. Decomposition of reaction system (RP/Cu/Sn) with the tin(IV) iodide should lead to the formation of the condensed phases represented by Cu4SnP10,Sn4P3, CuSn,Cu2P7, SnI4 and P2O5could be detected at a hot zone of the tube. The characterizations of the prepared BP were carried out also using Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and Raman spectroscopy.