Crystal growth of the 2D Janus rhodium chalcohalide RhSeCl

The rapidly growing interest in synthesising 2D Janus materials is supported by the numerous theoretical predictions of the unique properties of this material category. Here, we report the discovery of the novel 2D Janus material RhSeCl, which crystallises in a space group with a hexagonal symmetry, P6(3)mc, with the unit cell parameters a = 3.48760(10) and c = 11.5791(5) angstrom. Crystals of RhSeCl exhibit a plate-like morphology, which is typical of 2D materials. We present two methods of synthesising RhSeCl, either as polycrystalline powder via a solid-state reaction or as single crystals via chemical vapour transport, the latter allowing the control of the crystal size and thickness. Using XRD, SEM and EDX, we show that the described method has high reproducibility. The direct deposition of the 2D Janus crystal RhSeCl provides a broader approach to the study of the Janus phenomena and could further be adjusted to other promising element combinations.