Observation of size-dependent thermalization in CdSe nanocrystals using time-resolved photoluminescence spectroscopy

Daniel C. Hannah, Nicholas J. Dunn, Sandrine Ithurria, Dmitri V. Talapin, Lin X. Chen, Matthew Pelton, George C. Schatz, Richard D. Schaller

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33 Citations (Scopus)


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 languageEnglish
Article number177403
JournalPhysical review letters
Issue number17
Publication statusPublished - Oct 20 2011


ASJC Scopus subject areas

  • Physics and Astronomy(all)

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