Preparation, Exfoliation and Investigation of MPS₃ - Transition Metal Phosphorous Trisulfides

Transition metal phosphorous trisulfides (MPTs) are layered compounds with chemical formula MPS₃, where M is divalent metal, P is Phosphorous and S is Sulphur. In the past bulk crystals of MPTs were widely studied for application i.e. in lithium batteries [1]. Nowadays they are once again in scientific interest due to their anisotropic properties and possibility to obtain and study their monolayers [2].

MPTs are two dimensional (2D) semiconductors, also called layered semiconductors, as they are built from stacks of single molecular sheets. They have strong, covalent bonds within layer and between them there are only weak van der Waals interactions. The intra-layer interactions are 1-2 orders of magnitude stronger than inter-layer ones and this anisotropy of structure has great impact on their properties. For example, it is relatively simple to receive few or even monolayer forms or to intercalate these compounds. Moreover, such a decreasing of size in one dimensions leads to observing special phenomena in case of electrical or magnetic properties.

The poster will present synthesis and characterization of bulk, few and monolayers of MPTs, i.e. FePS₃. NiPS₃. Bulk crystals were obtained by vapor transport furnace synthesis and exfoliation was performed by two approaches: mechanical and chemical. Received products were characterized for example by SEM coupled with EDS, Raman spectroscopy (temperature depended measurements) and Atomic Force Microscopy (AFM).

Acknowledgments:

This work was supported by the European Comission via the Marie-Sklodowska Curie action Phonsi (H2020-MSCA-ITN-642656)

References:

[1] R. Brec, Solid State Ionics, 1986, vol. 22, no. 1, 1986.

[2] K.-z. Du et. al., ACS Nano, vol. 10, no. 2, 2016.