Abstract
We report heat dissipation times in semiconductor nanocrystals of CdSe. Specifically, a previously unresolved, subnanosecond decay component in the low-temperature photoluminescence decay dynamics exhibits longer decay lifetimes (tens to hundreds of picoseconds) for larger nanocrystals as well as a size-independent, ∼25-meV spectral shift. We attribute the fast relaxation to transient phonon-mediated relaxation arising from nonequilibrium acoustic phonons. Following acoustic phonon dissipation, the dark exciton state recombines more slowly via LO-phonon assistance resulting in the observed spectral shift. The measured relaxation time scales agree with classical calculations of thermal diffusion, indicating that interfacial thermal conductivity does not limit thermal transport in these semiconductor nanocrystal dispersions.
| Original language | English |
|---|---|
| Article number | 177403 |
| Journal | Physical Review Letters |
| Volume | 107 |
| Issue number | 17 |
| DOIs | |
| Publication status | Published - Oct 20 2011 |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
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Observation of size-dependent thermalization in CdSe nanocrystals using time-resolved photoluminescence spectroscopy. / Hannah, Daniel C.; Dunn, Nicholas J.; Ithurria, Sandrine; Talapin, Dmitri V.; Chen, Lin X.; Pelton, Matthew; Schatz, George C; Schaller, Richard D.
In: Physical Review Letters, Vol. 107, No. 17, 177403, 20.10.2011.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Observation of size-dependent thermalization in CdSe nanocrystals using time-resolved photoluminescence spectroscopy
AU - Hannah, Daniel C.
AU - Dunn, Nicholas J.
AU - Ithurria, Sandrine
AU - Talapin, Dmitri V.
AU - Chen, Lin X.
AU - Pelton, Matthew
AU - Schatz, George C
AU - Schaller, Richard D
PY - 2011/10/20
Y1 - 2011/10/20
N2 - We report heat dissipation times in semiconductor nanocrystals of CdSe. Specifically, a previously unresolved, subnanosecond decay component in the low-temperature photoluminescence decay dynamics exhibits longer decay lifetimes (tens to hundreds of picoseconds) for larger nanocrystals as well as a size-independent, ∼25-meV spectral shift. We attribute the fast relaxation to transient phonon-mediated relaxation arising from nonequilibrium acoustic phonons. Following acoustic phonon dissipation, the dark exciton state recombines more slowly via LO-phonon assistance resulting in the observed spectral shift. The measured relaxation time scales agree with classical calculations of thermal diffusion, indicating that interfacial thermal conductivity does not limit thermal transport in these semiconductor nanocrystal dispersions.
AB - We report heat dissipation times in semiconductor nanocrystals of CdSe. Specifically, a previously unresolved, subnanosecond decay component in the low-temperature photoluminescence decay dynamics exhibits longer decay lifetimes (tens to hundreds of picoseconds) for larger nanocrystals as well as a size-independent, ∼25-meV spectral shift. We attribute the fast relaxation to transient phonon-mediated relaxation arising from nonequilibrium acoustic phonons. Following acoustic phonon dissipation, the dark exciton state recombines more slowly via LO-phonon assistance resulting in the observed spectral shift. The measured relaxation time scales agree with classical calculations of thermal diffusion, indicating that interfacial thermal conductivity does not limit thermal transport in these semiconductor nanocrystal dispersions.
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U2 - 10.1103/PhysRevLett.107.177403
DO - 10.1103/PhysRevLett.107.177403
M3 - Article
VL - 107
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 17
M1 - 177403
ER -