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Ionov, L. ; Sapra, S. ; Synytska, A. ; Rogach, A. L. ; Feldmann, S. ; Stamm, M. ; Diez, S.
Fluorescent Composite Layers of Polymers and Semiconductor Nanocrystals as Environmental Sensors

ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 231: 500-PMSE MAR 26 2006

Here we suggest a novel approach for the design of fluorescent sensors based on the phenomenon of interference between fluorescence light directly emitted by a molecule or nanoparticle and fluorescence light, which is reflected from the mirror placed underneath. The emitted light can undergo either constructive or destructive interference with the reflected light. Thus, the intensity of the resulting signal is a periodic function of the separation of fluorescent particle from the reflecting surface. The period depends on the refractive index of the media, and on the wavelengths of illuminating and reflected light. Fluorescent particles located in the close vicinity to the mirror surface appear to be dark. Their apparent brightness increases with increasing distance from the mirror, passes through a maximum and then decreases again1. Hence, in the absence of quenching, variation in the brightness of fluorescent particle near the reflecting surface represents the change of the distance between them, thus providing the sensor signal related to this distance. Thereby, inserting a layer that is able to change separation of fluorescent species from the reflecting substrate depending on environmental conditions provides a simple and cheap strategy for the design of highly sensitive fluorescent environmental sensors.

Source
Polymeric Materials: Science and Engineering

Pages
847-848

DOI
http://oasys2.confex.com/acs/231nm/techprogram/P930621.HTM

Published
December 2006
 
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Publications

Departments

Nanostructured Materials