Exciton polarizability and absorption spectra in CdSe/ZnS nanocrystal quantum dots in electric fields

2013 ◽  
Vol 114 (4) ◽  
pp. 043709 ◽  
Author(s):  
Shudong Wu ◽  
Weiwei Xia
Keyword(s):  
Quantum Dots ◽  
Absorption Spectra ◽  
Electric Fields ◽  
Nanocrystal Quantum Dots

Synthesis and Characterization of CdSe Nanocrystal Quantum Dots by Solution-Liquid-Solid Method

2013 ◽  
Vol 750-752 ◽  
pp. 983-986
Author(s):  
Hai Yun Chen ◽  
Yu Kai Shan ◽  
Yu Yue Qin ◽  
Yong Ming Chuan ◽  
Ming Long Yuan
Keyword(s):  
Quantum Dots ◽  
Absorption Spectra ◽  
Synthesis And Characterization ◽  
Cdse Qds ◽  
Peak Wavelength ◽  
Transmission Electron Microcopy ◽  
Transmission Electron ◽  
Nanocrystal Quantum Dots ◽  
Bi Nanoparticles

The present work describes a solution-liquid-solid (SLS) synthesis route for the preparation of CdSe nanocrystal quantum dots using the low-melting-point Bi nanoparticles as catalysts. UV-vis absorption spectra were used to determine the growth of CdSe cluster. The shape and size distribution of the CdSe QDs were determined by analysis of Transmission electron microcopy (TEM) images. A peak wavelength of 399nm in the absorption spectra on day 5 indicated that the CdSe cluster formed. TEM micrographs showed that CdSe QDs had a relatively narrow distribution of QD size, and the diameter of CdSe QDs was about 4 nm. Our preliminary results illustrated that smaller size of CdSe QDs could be prepared by SLS method and it was small enough for bioimaging applications.

scholarly journals Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

2018 ◽  
Vol 9 ◽  
pp. 1544-1549 ◽  
Author(s):  
Margarita A Kurochkina ◽  
Elena A Konshina ◽  
Daria Khmelevskaia
Keyword(s):  
Quantum Dots ◽  
Liquid Crystals ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Dielectric Anisotropy ◽  
Vertical Position ◽  
Decay Times ◽  
Pl Intensity

We have experimentally investigated the effect of the reorientation of a nematic liquid crystal (LC) in an electric field on the photoluminescence (PL) of CdSe/ZnS semiconductor quantum dots (QDs). To the LC with positive dielectric anisotropy, 1 wt % QDs with a core diameter of 5 nm was added. We compared the change of PL intensity and decay times of QDs in LC cells with initially planar or vertically orientated molecules, i.e., in active or passive LC matrices. The PL intensity of the QDs increases four-fold in the active LC matrix and only 1.6-fold in the passive LC matrix without reorientation of the LC molecules. With increasing electric field strength, the quenching of QDs luminescence occurred in the active LC matrix, while the PL intensity did not change in the passive LC matrix. The change in the decay time with increasing electric field strength was similar to the behavior of the PL intensity. The observed buildup in the QDs luminescence can be associated with the transfer of energy from LC molecules to QDs. In a confocal microscope, we observed the increase of particle size and the redistribution of particles in the active LC matrix with the change of the electric field strength. At the same time, no significant changes occurred in the passive LC matrix. With the reorientation of LC molecules from the planar in vertical position in the LC active matrix, quenching of QD luminescence and an increase of the ion current took place simultaneously. The obtained results are interesting for controlling the PL intensity of semiconductor QDs in liquid crystals by the application of electric fields.

Insights into Reversible Dissolution of Colloidal CdSe Nanocrystal Quantum Dots

2010 ◽  
Vol 22 (21) ◽  
pp. 5973-5982 ◽  
Author(s):  
Jacqueline T. Siy ◽  
Michael H. Bartl
Keyword(s):  
Quantum Dots ◽  
Nanocrystal Quantum Dots
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