Boron, which is probably the most complex element in the periodic table [1], is a fascinating element with an extremely rich chemistry [2]. Boron-based materials comprise many covalent diamond-like and boron-rich compounds whose structures are three-dimensional nets of short and strong covalent bonds responsible for their extreme hardness. If new allotropes of boron are still regularly discovered under high pressure [3-6], the studies on synthesis of boron-based nanostructures including borides or even boron allotropes are very scarce. However, such new nanomaterials would raise high interest for properties like ultrahardness [1], catalysis properties [7], superconductivity [8], thermoelectricity [9], etc…

In this invited talk, I will show that the use of very high pressures and temperatures is the methodological key to control the composition and microstructure of a new bulk nanostructured ultrahard boron compound and then I will focus on a new promising pathway to reach nanostructured boron-rich materials, by combining colloidal chemistry and high pressure.

[1] J. Superhard Mater. 31, 285–291 (2009).

[2] Adv. Mater. 1604506 (2017).

[3] Nature 457, 863–867 (2009).

[4] High Press. Res. 33, 673–683 (2013).

[5] Science 350, 1513–1516 (2015).

[6] Physical Review B 95, 180102 (2017).

[7] Angew.Chemie Int. Ed. 52, 3241–3245 (2013).

[8] Nature 410, 63–64 (2001).

[9] MRS Proc. 234, 145(1991).