Fluorescence resonance energy transfer measured by spatial photon migration in CdSe-ZnS quantum dots colloidal systems as a function of concentration

• Published in: Applied physics letters Vol. 105; no. 20
• Main Authors: Azevedo, G., Monte, A. F. G., Reis, A. F., Messias, D. N.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 17-11-2014
• Subjects: Applied physics; CADMIUM SELENIDES; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Dependence; DIFFUSION LENGTH; Diffusion theory; Embedded systems; Energy measurement; ENERGY TRANSFER; FLUORESCENCE; MICROSCOPES; Migration; MIGRATION LENGTH; NANOSCIENCE AND NANOTECHNOLOGY; PHOTOLUMINESCENCE; PHOTONS; Propagation; QUANTUM DOTS; SPACE DEPENDENCE; SPATIAL DISTRIBUTION; Zinc sulfide; ZINC SULFIDES
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4902223

The study of the spatial photon migration as a function of the concentration brings into attention the problem of the energy transfer in quantum dot embedded systems. By measuring the photon propagation and its spatial dependence, it is possible to understand the whole dynamics in a quantum dot system, and also improve their concentration dependence to maximize energy propagation due to radiative and non-radiative processes. In this work, a confocal microscope was adapted to scan the spatial distribution of photoluminescence from CdSe-ZnS core-shell quantum dots in colloidal solutions. The energy migration between the quantum dots was monitored by the direct measurement of the photon diffusion length, according to the diffusion theory. We observed that the photon migration length decreases by increasing the quantum dot concentration, this kind of behavior has been regarded as a signature of Förster resonance energy transfer in the system.