Preparation of Black Phosphorus by the Mechanical Ball Milling Method and its Characterization

Abstract

In this paper, red phosphorus successfully turned to black phosphorus by the mechanical ball milling method. The samples were analyzed by the X-ray diffraction (XRD) method and by high resolution transmission electron microscopy (HRTEM). The XRD result showed that the black phosphorus obtained had small crystal size and a small, amorphous, broadly diffused peak of red phosphorus. The HRTEM analysis showed that the grain size of most of the black phosphorus was small (about 3-5nm). The electron diffraction pattern and the d-spacing on HRTEM correspond well to the characteristic peaks of black phosphorus, such as {111}, {021} and {151}. In some areas, the grain size of black phosphorus was large (about 20-50nm) and contained many defects in crystals. This showed that initially, the amorphous red phosphorus turned into black phosphorus nanocrystals under the action of mechanical milling. Subsequently, the grains were refined and became tiny grains under the action of a large number of edge dislocations in the crystals. During analysis of the TEM, the small size crystals of black phosphorus were rapidly non-crystallized and seriously damaged by electron irradiation. Therefore only the big grains were left after 30 minutes of irradiation.