Fig. 1: Synthesis and characterization of three crystalline red phosphorus (RP) powders.
From: Phase-selective synthesis and polymorphic transformation of crystalline red phosphorus
a Schematic diagram of the solid-phase thermal transformation (STT) synthesis setup based on a CVT reaction system. b Temperature profiles of the hot end during the reaction process. c Scanning electron microscopy (SEM) images of the different forms of RP. Inset: Images of different RP powders. d Powder X-ray diffraction (PXRD) patterns of Form II, IV, and V compared with standard reference patterns. The unit of intensity is arbitrary units (a.u.). e Raman spectrum of Form II, IV, and V, measured under 532 nm excitation. The “*” marks the Raman vibration peak at 490 cm⁻¹, used to distinguish between Form IV and V. f High-resolution X-ray photoelectron spectroscopy (XPS) of P 2p in Form II. g Ultraviolet-visible-near infrared (UV-vis-NIR) absorption spectra h and corresponding Tauc-plot curves of Form II, IV, and V. Note: Since the three crystalline RP are indirect bandgap semiconductors, \(n\) is 1/2 in the \({\left[F\left({R}_{\infty }\right){hv}\right]}^{n}={{\rm{A}}}\left({hv}-{E}_{g}\right)\) according to previous report50. i Photoluminescence (PL) spectra of Form II, IV, and V.
