Revealing the exciton fine structure of PbSe nanocrystal quantum dots using optical spectroscopy in high magnetic fields

R. D. Schaller, S. A. Crooker, D. A. Bussian, J. M. Pietryga, J. Joo, V. I. Klimov

Research output: Contribution to journalArticle

33 Citations (Scopus)


We measure the photoluminescence lifetime τ of excitons in colloidal PbSe nanocrystals (NCs) at low temperatures to 270 mK and in high magnetic fields to 15 T. For all NCs, τ increases sharply below 10 K but saturates by 500 mK. In contrast to the usual picture of well-separated "bright" and "dark" exciton states (found, e.g., in CdSe NCs), these dynamics fit remarkably well to a system having two exciton states with comparable-but small-oscillator strengths that are separated by only 300-900μeV depending on NC size. Importantly, magnetic fields reduce τ below 10 K, consistent with field-induced mixing between the two states. Magnetic-circular dichroism studies reveal exciton g factors from 2-5, and magnetophotoluminescence shows >10% circularly polarized emission.

Original languageEnglish
Article number067403
JournalPhysical review letters
Issue number6
Publication statusPublished - Aug 4 2010


ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this