title: Subsecond luminescence intensity fluctuations of single CdSe quantum dots.
abstract: Photoluminescence (PL) intermittency characteristics are examined for single quantum dots (QDs) in a CdSe QD sample synthesized at a slow rate at 75 degrees C. Although the PL quantum efficiency was relatively low ( approximately 0.25), we noticed that the PL intensity of single CdSe QDs fluctuated on a subsecond time scale with short-lived "on" and "off" states. The subsecond PL intensity fluctuations of CdSe QDs are different from "on" and "off" PL blinking generally observed for QDs fluctuating on a millisecond to minute time scale. We characterized single QDs by identifying polarized excitations, topographic imaging using atomic force microscopy (AFM), and transmission electron microscopy (TEM). From analysis of the PL intensity trajectories from >100 single CdSe QDs, the average intermittency time was 213 ms. From the PL quantum efficiency, slow growth of QDs, intensity trajectory analyses, and previous reports relating surface trap states and PL properties of QDs, we attribute the subsecond PL intensity fluctuations of single CdSe QDs and short-lived "on" and "off" states to a high-density distribution of homogeneous surface trap states.
authors.affiliation: Nano-Bioanalysis Team, Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14 Hayashi-cho, Takamatsu Kagawa 761-0395, Japan.
authors.forename: Vasudevanpillai
authors.initials: V
authors.lastname: Biju
authors.forename: Yoji
authors.initials: Y
authors.lastname: Makita
authors.forename: Toshimi
authors.initials: T
authors.lastname: Nagase
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Yamaoka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Baba
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ishikawa
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D049449:Luminescence; D010777:Photochemistry; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013997:Time Factors
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; C058667:cadmium selenide