TY - JOUR
T1 - Influence of the dielectric environment on the photoluminescence intermittency of CdSe quantum dots
AU - Issac, Abey
AU - Krasselt, Cornelius
AU - Cichos, Frank
AU - Von Borczyskowski, Christian
PY - 2012/9/17
Y1 - 2012/9/17
N2 - We show experimentally that the photoluminescence intermittency (blinking) of single CdSe quantum dots (QDs) is influenced by the dielectric properties of the embedding environment (matrix), the type of ligands and the capping shell. For the on-times, we observe (and tentatively explain) a strong deviation from the commonly reported inverse power law behaviour, which can be taken into account by an exponential cut-off at long times. We assign this component to the photoejection of the electron, while the power law behaviour is a combination of hole- and electron-trapping processes. The cut-off times and their distributions depend strongly on the polarity of the environment. Also, the off-times show, though on a much longer timescale, deviations from the inverse power laws. We suggest a model including surface states and self-trapped states, which quantitatively explains the experimental observations.
AB - We show experimentally that the photoluminescence intermittency (blinking) of single CdSe quantum dots (QDs) is influenced by the dielectric properties of the embedding environment (matrix), the type of ligands and the capping shell. For the on-times, we observe (and tentatively explain) a strong deviation from the commonly reported inverse power law behaviour, which can be taken into account by an exponential cut-off at long times. We assign this component to the photoejection of the electron, while the power law behaviour is a combination of hole- and electron-trapping processes. The cut-off times and their distributions depend strongly on the polarity of the environment. Also, the off-times show, though on a much longer timescale, deviations from the inverse power laws. We suggest a model including surface states and self-trapped states, which quantitatively explains the experimental observations.
KW - blinking
KW - photoluminescence
KW - quantum dots
KW - single-molecule studies
KW - trap states
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U2 - 10.1002/cphc.201101040
DO - 10.1002/cphc.201101040
M3 - Article
C2 - 22753139
AN - SCOPUS:84866128664
SN - 1439-4235
VL - 13
SP - 3223
EP - 3230
JO - ChemPhysChem
JF - ChemPhysChem
IS - 13
ER -