Lee, Steven F and Osborne, Mark A (2007) Photodynamics of a Single Quantum Dot: Fluorescence Activation, Enhancement, Intermittency, and Decay. Journal of the American Chemical Society, 129 (29). pp. 8936-8937. ISSN 0002-7863

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Abstract

The observation of photoluminescence (PL) activation, enhancement, fluorescence intermittency (FI), and decay over the photochemical lifetimes of single quantum dots (QD) is reported. The ability to count individual QDs along with PL intensities has revealed a measurable nonlinear correlation between the total fluorescence and QD population that is the result of enhancement and decay in the quantum yield (QY) of individual dots. This allows the differentiation between ensemble PL enhancement due to the fluorescence activation of a dark, non-emitting fraction of QDs and that due to genuine QY modification in individual nanocrystals. The evolution of the bright, fluorescent population under continuous illumination is seen to closely follow that of the intermediate in a consecutive elementary reactions scheme. Spectral separation of QD fluorescence trajectories into red and blue components indicates that PL decay is not necessarily associated with blue-shifting of the emission wavelength.

Item Type:	Article
Additional Information:	First report of photoluminescence enhancement in inividual semiconductor nanocrystals and the differentiation between the apparent enhancement of the ensemble due to a photo-induced activation of a non-fluorescent dark fraction and genuine quantum yield enhancement at the single quantum dot level.
Schools and Departments:	School of Life Sciences > Chemistry
Depositing User:	Steven Lee
Date Deposited:	06 Feb 2012 21:14
Last Modified:	29 Mar 2012 10:39
URI:	http://sro.sussex.ac.uk/id/eprint/30402

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