Synthesis and characterisation of As3MnS6(NH4) crystal

• Main Author: Ng, Yu Ting.
• Other Authors: School of Materials Science and Engineering
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Materials::Photonics and optoelectronics materials
• Online Access: http://hdl.handle.net/10356/48436
• Institution: Nanyang Technological University

Metal chalcogenides have properties which see many potential applications in areas such as fast-ion conductivity, nonlinear optics and electronics. The ability to tailor their properties and structures using several synthesis methods makes it possible for the synthesis of novel metal chalcogenide materials with multi-functionality. In this report, a novel metal chalcogenide material, As3MnS6(NH4), has been synthesised via low temperature solvothermal synthesis, where the precursors As2S3, Mn, N2H4∙H2O and [HMIM]Cl are heated in an oven for 5 days at 140oC. The material, which is in the form of a dark red crystal, has a 3D open framework structure formed by the linking of semi-cubic structures via sulphur bridges. NH4+ ions can be found in the open channels and are loosely bonded to As atoms by weak van der Waals forces. The material is found to have an optical band gap of 2.24eV, a decomposition temperature between 250oC to 400oC and weak antiferromagnetic interactions between the Mn2+ ions. Metal chalcogenides, open framework structures, the synthesis method used, ionic liquids, the solvent used, recent works and properties of As2S3 will also be discussed.