title: Dynamic fluctuations in ultrasmall nanocrystals induce white light emission.
abstract: Individual ultrasmall CdSe nanocrystals have recently been found to emit white light, but the ultimate origin of the phenomenon has remained elusive. Here we use a combination of state-of-the-art experiment and theory to show that excitation sets the ultrasmall nanocrystals into a fluxional state. Their energy gaps vary continuously on a femtosecond time scale, so that even an individual nanocrystal can emit across the entire visual range. In addition, we observe the outer layers of the larger monochromatic emitting nanocrystals to be fluxional. Such fluxionality should be considered when optimizing nanocrystals for applications. Thus, small is indeed different, but ultrasmall is different yet again.
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States. timothy.pennycook@materials.ox.ac.uk
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Pennycook
authors.forename: James R
authors.initials: JR
authors.lastname: McBride
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Rosenthal
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Pennycook
authors.forename: Sokrates T
authors.initials: ST
authors.lastname: Pantelides
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D003116:Color; D008029:Lighting / Q000379:methods*; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D018036:Selenium Compounds / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; C058667:cadmium selenide