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Abstract
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In this study, size dependent interaction of thioglycolic acid capped CdTe quantum dots (QDs)
and dopamine, as an important bio-molecule, is studied via fluorescence spectroscopy. The growth
process and characterization of the three different size QDs (1.87, 2.98, and 3.34 nm) are studied
by photoluminescence spectroscopy, UV-Vis absorption, transmission electron microscopy, X-ray
diffraction, and Fourier transform infrared spectroscopy. It found that the interaction of CdTe QDs
with dopamine is strongly depended on the QDs particle size, and CdTe QDs with particle size of
3.34 nm was recommended to be applicable for analytical applications. Based on the quenching
effect of dopamine on the fluorescence intensity of the appropriate QDs (3.34 nm), a good linear
correlation between dopamine concentration (1–220 M) and fluorescence intensity is obtained
resulting a detection limit of 0.06 M. The interaction mechanism of the dopamine with different
size QDs was thoroughly explained.
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