title: Quantum dot photon statistics measured by three-dimensional particle tracking.
abstract: We present an instrument for performing correlation spectroscopy on single fluorescent particles while tracking their Brownian motion in three dimensions using real-time feedback. By tracking CdSe/ZnS quantum dots in water (diffusion coefficient approximately 20 microm2/s), we make the first measurements of photon antibunching (at approximately 10 ns) on single fluorophores free in solution and find fluorescence lifetime heterogeneity within a quantum dot sample. In addition, we show that 2-mercaptoethanol suppresses short time-scale intermittency (1 ms to 1 s) in quantum dot fluorescence by reducing time spent in the off-state.
authors.affiliation: Physical Measurement and Control 266-33, California Institute of Technology, Pasadena, California 91125, USA. mchale@caltech.edu
authors.forename: Kevin
authors.initials: K
authors.lastname: McHale
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Berglund
authors.forename: Hideo
authors.initials: H
authors.lastname: Mabuchi
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D004058:Diffusion; D004867:Equipment Design; D008623:Mercaptoethanol / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D017785:Photons; D011336:Probability; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D013997:Time Factors; D014867:Water / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D014867:Water; D008623:Mercaptoethanol; C058667:cadmium selenide; C031238:zinc sulfide