In an effort to elucidate the spin (rather than charge) degrees of freedom in colloidal semiconductor nanocrystal quantum dots, we report on a series of static and time-resolved photoluminescence measurements of colloidal CdSe quantum dots in ultra-high magnetic fields up to 45 Tesla. At low temperatures (1.5 K - 40 K), the steady-state photoluminescence (PL) develops a high degree of circular polarization with applied magnetic field, indicating the presence of spin-polarized excitons. Time-resolved PL studies reveal a marked decrease in radiative exciton lifetime with increasing magnetic field and temperature. Except for an initial burst of unpolarized PL immediately following photoexcitation, high-field time-resolved PL measurements reveal a constant degree of circular polarization throughout the entire exciton lifetime, even in the presence of pronounced exciton transfer via Forster energy transfer processes.
@article{arxiv.cond-mat/0511676,
title = {Time- and Polarization-Resolved Optical Spectroscopy of Colloidal CdSe Nanocrystal Quantum Dots in High Magnetic Fields},
author = {Madalina Furis and Jennifer Hollingsworth and Victor I. Klimov and Scott A. Crooker},
journal= {arXiv preprint arXiv:cond-mat/0511676},
year = {2007}
}
Comments
This paper has been published in J.Phys. Chem B 109, 15332 (2005)