Room-Temperature Exciton Storage in Elongated Semiconductor Nanocrystals

R. M. Kraus, P. G. Lagoudakis, A. L. Rogach, D. V. Talapin, H. Weller, J. M. Lupton, and J. Feldmann

Phys. Rev. Lett. 98, 017401 – Published 4 January 2007

Abstract

The excited state of colloidal nanoheterostructures consisting of a spherical CdSe nanocrystal with an epitaxially attached CdS rod can be perturbed effectively by electric fields. Field-induced fluorescence quenching coincides with a conversion of the excited state species from the bright exciton to a metastable trapped state (dark exciton) characterized by a power-law luminescence decay. The conversion is reversible so that up to 10% of quenched excitons recombine radiatively post turn-off of a $1 μ s$ field pulse, increasing the delayed luminescence by a factor of 80. Excitons can be stored for up to $10^{5}$ times the natural lifetime, opening up applications in optical memory elements.

Received 11 July 2006

DOI:https://doi.org/10.1103/PhysRevLett.98.017401

Authors & Affiliations

R. M. Kraus¹, P. G. Lagoudakis^1,*,†,‡, A. L. Rogach¹, D. V. Talapin^2,§, H. Weller², J. M. Lupton^1,3,*,∥, and J. Feldmann¹

¹Photonics and Optoelectronics Group, Physics Department and CeNS, Ludwig-Maximilians-Universität, Amalienstraße 54, 80799 München, Germany
²Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
³Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA

^*Corresponding author.
^†Electronic address: pavlos.lagoudakis@soton.ac.uk
^‡Present address: School of Physics and Astronomy, University of Southampton, United Kingdom.
^§Present address: The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
^∥Electronic address: lupton@physics.utah.edu

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Vol. 98, Iss. 1 — 5 January 2007

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