Manganese Sulfide (MnS) Nanocrystals: Synthesis, Properties, and Applications

Manganese(II) sulfide (MnS) is an interesting material for both fundamental and applicative research, especially when its bulk properties are modulated by reducing the size into the nanometric region (< 100 nm). Due to its polymorphism, MnS is an attractive material to develop synthetic strategies for polymorphism control. We have reviewed the literature concerning MnS nanosystems having at least one dimension smaller than 100 nm. Successful synthetic techniques for the preparation of zeroand one-dimensional MnS nanosystems (either homogeneous and heterogeneous) with size, shape, and polymorphism control are presented with emphasis on solvothermal techniques and on studies devoted to understanding the growth mechanism and the polymorphism. Properties and applications are collected in three broad areas corresponding to nanosize MnS used as an optical, electric, and magnetic material. MnS has attracting properties such as its large bandgap, which makes it promising for emission in the ultraviolet region. The magnetic properties have also arisen attention since MnS is antiferromagnetic at low temperature and (super)paramagnetic at room temperature. Finally, the layered structure of the hexagonal polymorph is responsible for the good performance of nanosize MnS as a lithium-ion battery electrode or supercapacitor material since the insertion/exchange of small ions is easy.