title: Size-dependent absolute quantum yields for size-separated colloidally-stable silicon nanocrystals.
abstract: Size-selective precipitation was used to successfully separate colloidally stable allylbenzene-capped silicon nanocrystals into several visible emitting monodisperse fractions traversing the quantum size effect range of 1-5 nm. This enabled the measurement of the absolute quantum yield and lifetime of photoluminescence of allylbenzene-capped silicon nanocrystals as a function of size. The absolute quantum yield and lifetime are found to monotonically decrease with decreasing nanocrystal size, which implies that nonradiative vibrational and surface defect effects overwhelm spatial confinement effects that favor radiative relaxation. Visible emission absolute quantum yields as high as 43% speak well for the development of "green" silicon nanocrystal color-tunable light emitting diodes that can potentially match the performance of their toxic heavy metal chalcogenide counterparts.
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Center for Inorganic and Polymeric Nanomaterials, Chemistry Department, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada, M5S3H6.
authors.forename: Melanie L
authors.initials: ML
authors.lastname: Mastronardi
authors.forename: Florian
authors.initials: F
authors.lastname: Maier-Flaig
authors.forename: Daniel
authors.initials: D
authors.lastname: Faulkner
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Henderson
authors.forename: Christian
authors.initials: C
authors.lastname: Kübel
authors.forename: Uli
authors.initials: U
authors.lastname: Lemmer
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Ozin
mesh_terms: D011232:Chemical Precipitation; D003102:Colloids / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D003102:Colloids; D046911:Macromolecular Substances; D012825:Silicon