title: Sample-averaged biexciton quantum yield measured by solution-phase photon correlation.
abstract: The brightness of nanoscale optical materials such as semiconductor nanocrystals is currently limited in high excitation flux applications by inefficient multiexciton fluorescence. We have devised a solution-phase photon correlation measurement that can conveniently and reliably measure the average biexciton-to-exciton quantum yield ratio of an entire sample without user selection bias. This technique can be used to investigate the multiexciton recombination dynamics of a broad scope of synthetically underdeveloped materials, including those with low exciton quantum yields and poor fluorescence stability. Here, we have applied this method to measure weak biexciton fluorescence in samples of visible-emitting InP/ZnS and InAs/ZnS core/shell nanocrystals, and to demonstrate that a rapid CdS shell growth procedure can markedly increase the biexciton fluorescence of CdSe nanocrystals.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Beyler
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Bischof
authors.forename: Jian
authors.initials: J
authors.lastname: Cui
authors.forename: Igor
authors.initials: I
authors.lastname: Coropceanu
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Harris
authors.forename: Moungi G
authors.initials: MG
authors.lastname: Bawendi
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry* / Q000528:radiation effects*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods; D010783:Photometry / Q000295:instrumentation* / Q000379:methods; D017785:Photons; D018401:Sample Size; D018036:Selenium Compounds / Q000737:chemistry* / Q000528:radiation effects*; D013050:Spectrometry, Fluorescence / Q000295:instrumentation* / Q000379:methods
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; C058667:cadmium selenide
keywords: Photon correlation; multiexcitons; semiconductor nanocrystals; single-molecule spectroscopy