Chemical Vapor Transport Synthesis of Pb2P2Se6 Crystals and their Optical Properties

Author of the article:JI Leilei1,2, ZHU Mengqin1,2, LI Fangpei1,2, JIE Wanqi1,2

Author's Workplace：1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China; 2. School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China

Key Words：Pb2P2Se6; chemical vapor transport; transmittance; optical properties

Abstract：： Ternary metal phosphorus trichalcogenide Pb2P2Se6 crystals have attracted wide attention because of their potential applications in optoelectronics. However, it is difficult to synthesize due to containing P, which has characteristics of flammability and explosive property. Here, we grew pure Pb2P2Se6 single crystals by the chemical vapor transport (CVT) method using NH4Cl as a transport agent from solid state synthesized polycrystals. The as-grown tetrahedron crystal exposes the (011) crystallographic plane with angles of 62° and 118°. The experimental XRD pattern reveals that the single crystal crystallizes in a monoclinic structure with the P21/n space group with lattice parameters of a=6.897 A，b=7.642 A， c=9.696 A and β=91.5°. In addition, the infrared transmittance of the crystal is 50% in the range of 1 000~4 000 cm-1, and the band gap is 1.89 eV, as determined by the UV-Vis-IR transmission spectrum.