Optical measurements on phosphorus polymorphs.

The anisotropic electronic structure of phosphorene makes it promising, for research and technological applications. Its polymorphs are White Phosphorus, which transforms into Red or Violet at 280 °C and 550 °C, and Black Phosphorus obtained from White applying pressure (12000 Bar) or trough catalysis. This research focuses on alternative synthesis methods for these, given their prohibitive cost, using common available materials.

Method 1: Matches’ heads were crushed with a blade to detach the material; it is then combusted in a Petri dish, mixed in 5 mL methanol for 30 h, at 26-32 °C, 45-47% humidity, and ground to a fine powder in an agate mortar. 146 mg were heated to 200 °C/65 h.

Method 2: Using tweezers and a cotton swab the strips are covered with acetone for a few seconds and scraped. The material is mixed in 20 mL acetone for 2 h, at 24 °C, 45 % humidity, air dried and ground to a fine powder. 118 mg were heated to 200 °C/65 h.

X-ray powder diffraction (XRD) analysis of the samples shows, for Method 1: SrP, Sr3P4O13, P2O5 and Sr2BrP. For Method 2: PBr5, and SrP. Simultaneous calorimetric and thermogravimetric analysis show the binary and ternary compounds observed by XRD. UV-Vis analysis shows the influence of the polymorphs and other impurities. Color changes are present.