Characterization and Optimization for Efficient Synthesis of Violet Phosphorus Crystal

Abstract

The discovery and construction of novel two-dimensional (2D) materials are driving forces for technological advancement. Among them, violet phosphorus (VP)—a structurally ordered and thermodynamically stable allotrope of phosphorus—exhibits a well-defined layered framework, superior crystallinity, and enhanced environmental stability compared with black phosphorus. However, the absence of an efficient and controllable growth strategy has severely constrained both its fundamental understanding and functional implementation. Herein, tellurium (Te) and iodine (I) were introduced as mineralizers in a chemical vapor transport (CVT) system to drive the transformation of amorphous red phosphorus into highly crystalline VP. This method enables rapid and uniform crystal growth, yielding plate-like VP with strong (004) orientation, sharp lattice fringes, and a remarkably high yield (~95%) within 15 h. The analysis of the structure and optical properties reveals significant light absorption activity, and it has a band gap of approximately 1.8 eV, indicating excellent semiconductor and light response characteristics. Furthermore, compared to black phosphorus the as-grown VP crystals exhibit robust air stability, maintaining their structural integrity and optical characteristics over extended periods. This work provides an efficient and scalable route to produce high-quality VP crystals, thereby advancing their applications in next-generation optoelectronics, photodetection, and energy conversion systems.