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Optical Engineering

Concentration and size dependence of peak wavelength shift on quantum dots in colloidal suspension
Author(s): Benjamin S. Rinehart; Caroline G. L. Cao
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Paper Abstract

Quantum dots (QDs) are semiconductor nanocrystals that have significant advantages over organic fluorophores, including their extremely narrow Gaussian emission bands and broad absorption bands. Thus, QDs have a wide range of potential applications, such as in quantum computing, photovoltaic cells, biological sensing, and electronics. For these applications, aliasing provides a detrimental effect on signal identification efficiency. This can be avoided through characterization of the QD fluorescence signals. Characterization of the emissivity of CdTe QDs as a function of concentration (1 to 10  mg/ml aqueous) was conducted on 12 commercially available CdTe QDs (emission peaks 550 to 730 nm). The samples were excited by a 50-mW 405-nm laser with emission collected via a free-space CCD spectrometer. All QDs showed a redshift effect as concentration increased. On average, the CdTe QDs exhibited a maximum shift of +35.6  nm at 10  mg/ml and a minimum shift of +27.24  nm at 1  mg/ml, indicating a concentration dependence for shift magnitude. The concentration-dependent redshift function can be used to predict emission response as QD concentration is changed in a complex system.

Paper Details

Date Published: 19 August 2016
PDF: 7 pages
Opt. Eng. 55(8) 087106 doi: 10.1117/1.OE.55.8.087106
Published in: Optical Engineering Volume 55, Issue 8
Show Author Affiliations
Benjamin S. Rinehart, Wright State Univ. (United States)
Caroline G. L. Cao, Wright State Univ. (United States)

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