Influence of synthesis parameters on size, composition and fluorescent properties of CdZnSeS alloyed quantum dots

Abstract

Quantum dots (QDs) are nanocrystals of semiconductor materials with a diameter of 2 to 15 nm, coated with a stabilizing layer of organic molecules. Due to their unique optical properties, QDs are used in various fields, from engineering to biological analysis. Quantum confinement effect causes the need of changing the size of QDs to vary the optical properties, what limits the application of QDs in some cases. Studies on removing such limitations led to the invention of fundamentally new types of QDs, in which the optical properties can be controlled by changing the composition of the QDs – multicomponent alloyed quantum dots (AQDs). Varying the precursor ratio in QDs synthesis provides opportunities for changing the optical properties, however increase in the number of components complicates the synthesis and, accordingly, the need of deep understanding of the mechanisms of crystal formation is required.
In this work CdZnSeS AQDs of a gradient structure were in non-polar solvent via one-pot hot injection method were synthesized under different conditions such as reagents concentration, amount of stabilizer and precursor ratio. Acquired batch of alloyed CdZnSeS QDs samples with fluorescence peak wavelengths in 530-630 nm region was studied in detail including comparison of their real and theoretical composition, characterization of fluorescent properties and inspection of form and size of the nanocrystals. The revealed dependencies of synthesis conditions on fluorescent properties are presented and assumptions are made about the growth mechanisms of nanocrystals in this synthesis system.

Speaker

Kornilov Danila
Saratov State University
Russian Federation

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