title: CdSeS/ZnS alloyed nanocrystal lifetime and blinking studies under electrochemical control.
abstract: Alloyed CdSeS nanocrystals allow tuning between the CdSe and CdS band edges while remaining relatively small. The CdSeS cores also lead to a reduced electron confinement energy and a slower biexciton decay rate compared to CdSe cores of similar sizes. A ZnS shell synthesis procedure allows stable CdSeS/ZnS colloidal quantum dots (QDs) suitable for single dot imaging. These are compared to CdSe/ZnS of similar core size. The blinking off-exponents of the CdSeS/ZnS dots in air and on a glass substrate were slightly larger. Using electrochemistry with ensemble and single dot measurements, the trion lifetime of CdSeS/ZnS dot is resolved to be ~0.75 ns, while it is about 0.15 ns for CdSe/ZnS. In addition, the blinking behavior of single CdSeS/ZnS QDs is largely suppressed when in the trion state.
authors.affiliation: James Franck Institute, 929 E. 57th Street, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Qin
authors.forename: Raman A
authors.initials: RA
authors.lastname: Shah
authors.forename: Philippe
authors.initials: P
authors.lastname: Guyot-Sionnest
mesh_terms: D000497:Alloys / Q000737:chemistry / Q000528:radiation effects; D019187:Cadmium Compounds / Q000737:chemistry* / Q000528:radiation effects; D004574:Electromagnetic Fields; D008422:Materials Testing; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry* / Q000528:radiation effects; D017967:Zinc Compounds / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D000497:Alloys; D019187:Cadmium Compounds; D018036:Selenium Compounds; D017967:Zinc Compounds; C058667:cadmium selenide; C044696:zinc selenide