Ultrastable silicon nanocrystals due to electron delocalization.

Abstract

We report a new nanocrystalline form of silicon that gives birth to pure hydrogenated silicon nanocrystals that absorb light in the ultraviolet, visible, and infrared spectral region despite their small size of only 1 nm and without the need for expensive or toxic metal atoms. On the basis of first-principles calculations, we demonstrate that those pure, but overcoordinated silicon nanocrystals are more stable than any other known silicon nanocrystals due to electron delocalization and that they form spontaneously via self-assembly. Therefore, we predict their immediate application in fields ranging from photovoltaic and light-emitting devices to photothermal cancer treatment.