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https://doi.org/10.3938/NPSM.69.31
Effects of Precursor Molar Concentration on the Characteristics of CdSe QDs Synthesized at Low Temperature
New Phys.: Sae Mulli 2019; 69: 31~40
Published online January 31, 2019;  https://doi.org/10.3938/NPSM.69.31
© 2019 New Physics: Sae Mulli.

Sang-Hun LEE, Eun-Bee JUNG, Gyeong-Sub LIM, Il-Gon KIM, Dong-Sun YOO*

Department of Physics, Changwon National University, Changwon 51140, Korea
Correspondence to: dsyoo@changwon.ac.kr
Received August 18, 2018; Revised November 4, 2018; Accepted November 16, 2018.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
We fabricated CdSe quantum dots (QDs) by using Cd-oleate, Se-trioctylphosphine (Se-TOP) and octadecene under molar concenteraions of 10, 25, 50, 150 and 250 mM to investigate the effects of concentration on the characteristics of the QDs. The ratio of Cd:Se was 1:1 and the synthesis temperature was 180 $^\circ$C. The sizes of the QDs increased for 60 minutes, and the photoluminescence (PL) intensities increased monotonically for 30 minutes for concentrations 25 mM. However, for high concentrations above 150 mM, the normal growth mode was quenched between 1 minute and 10 minutes and the growth of QDs slowed; the PL intensities decreased dramatically after 10 minutes. The quantum yields of all the QDs synthesized within 30 minutes decreased with increasing molar concentration. The Stokes shifts and the full widths at half maximum (FWHMs) of the PL spectra decreased with increasing synthesis time when the concentrations was below 25 mM. All synthesized QDs had a zinc-blende structure, and the concentration did not affect that structure. In the Fourier transform infrared (FT-IR) spectra, the absorptions associated with the Cd stretching band and the Cd-oleate bands increased with increasing QD size.
PACS numbers: 78.67.Hc
Keywords: CdSe quantum dot, Cd-oleate, Se-TOP, Molar concentration, Photoluminescence spectra, Growth rate, Quantum yields, XRD


January 2019, 69 (1)
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