Spontaneous Spectral Diffusion in CdSe Quantum Dots.
Spectral diffusion of the emission line of single colloidal nanocrystals is generally regarded as a random process. Here, we show that each new spectral position has a finite memory of previous spectral positions, as evidenced by persistent anticorrelations in time series of spectral jumps. The anticorrelation indicates that there is an enhanced probability of the charge distribution around the nanocrystal returning to a previous configuration. We show both statistically and directly that this memory manifests as an observable spontaneous "relaxation" in the absence of a pump laser, so that spectral diffusion progresses in a manner of "two steps forward and one step back".
†Université Bordeaux, LP2N, F-33405 Talence, France.
Mark J
MJ
Fernée
§School of Physical Sciences, The University of Queensland, Queensland 4072, Australia.
Taras
T
Plakhotnik
⊥Université Bordeaux, LOMA, F-33405 Talence, France.
Yann
Y
Louyer
#Department of Physics, King's College London, Strand, London, WC2R 2LS United Kingdom.
Bradley N
BN
Littleton
∥School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
Christian
C
Potzner
†Université Bordeaux, LP2N, F-33405 Talence, France.
Philippe
P
Tamarat
∥School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
Paul
P
Mulvaney
†Université Bordeaux, LP2N, F-33405 Talence, France.
Brahim
B
Lounis
CdSe nanocrystals; CdSe quantum dots; cryogenic photoluminescence; single quantum dot photoluminescence; single quantum dot spectroscopy; spectral diffusion; surface phenomena