Credit: Illustration by Peter Allen, Institute for Molecular Engineering, University of Chicago
In this illustration, silicon quantum dots are shown in various states of “blinking.” The “on” crystals emit light (represented by a white dot) as an excited electron sheds excess energy as a photon. The “off” crystals are dark, because their electrons (yellow) are trapped in surface defects and siphon off energy through other paths, like heat or lattice vibrations.