Large Stokes Shifted Quaternary Copper Cadmium Sulfide Selenide Quantum Dots Waveguides

2021 ◽  
Author(s):  
Dipanwita Roy ◽  
Piyush Kanti Sarkar ◽  
Amit Dalui ◽  
Uttam Kumar Ghorai ◽  
Dharmendra K Gupta ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cadmium Sulfide ◽  
Stokes Shift ◽  
Colloidal Synthesis ◽  
Synthesis Route ◽  
Luminescence Efficiency ◽  
First Time

Stokes shift engineering of quantum dots is an attractive approach to enhance luminescence efficiency by reducing reabsorption losses. We report for the first time the colloidal synthesis route of a...

scholarly journals Structure and effects of annealing in colloidal matrix-free Ge quantum dots

2015 ◽  
Vol 22 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Yuanpeng Zhang ◽  
Ali Karatutlu ◽  
Osman Ersoy ◽  
William Little ◽  
Giannantonio Cibin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Colloidal Synthesis ◽  
Appreciable Amount ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Route ◽  
Nano Crystalline ◽  
Different Temperatures ◽  
Ge Quantum Dots ◽  
Long Range Ordering

The structure of small (2–5 nm) Ge quantum dots prepared by the colloidal synthesis route is examined. Samples were synthesized using either GeO2or GeCl4as precursor. As-prepared samples were further annealed under Ar or H2/Ar atmosphere at different temperatures in order to understand the effect of annealing on their structure. It was found that as-prepared samples possess distinctly different structures depending on their synthesis route as indicated by their long-range ordering. An appreciable amount of oxygen was found to be bound to Ge in samples prepared with GeO2as a precursor; however, not for GeCl4. Based on combined transmission electron microscope, Raman, X-ray diffraction and X-ray absorption measurements, it is suggested that as-prepared samples are best described by the core-shell model with a small nano-crystalline core and an amorphous outer layer terminated either with oxygen or hydrogen depending on the synthesis route. Annealing in an H2Ar atmosphere leads to sample crystallization and further nanoparticle growth, while at the same time reducing the Ge—O bonding. X-ray diffraction measurements for as-prepared and annealed samples indicate that diamond-type and metastable phases are present.

scholarly journals Potential Harm of Maltodextrin‐Coated Cadmium Sulfide Quantum Dots in Embryos and Fetuses

10.5772/64653 ◽  
2016 ◽  
Author(s):  
Jorge Reyes-Esparza ◽  
Janet Sánchez-Quevedo ◽  
Antonieta Gómez-Solís ◽  
Patricia Rodríguez-Fragoso ◽  
Gerardo González De la Cruz ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cadmium Sulfide ◽  
Potential Harm

The Emission Property of Phosphors LEDs Based on ZnCuInS/ZnSe/ZnS Quantum Dots

2014 ◽  
Vol 989-994 ◽  
pp. 623-625
Author(s):  
Ke Bi ◽  
Wen Yan Liu ◽  
Tian Yue Xu ◽  
Tie Qiang Zhang ◽  
Yu Zhang
Keyword(s):  
Quantum Dots ◽  
Photoluminescence Spectrum ◽  
Stokes Shift ◽  
Core Shell ◽  
Photoluminescence Properties ◽  
Red Emission ◽  
Light Emitting ◽  
Quantum Size ◽  
Gan Led ◽  
Photoluminescence Peak

.In this research, ZnCuInS/ZnSe/ZnS quantum dots (QDs) have been studied as an excellent red emitting source for blue GaN LED because of its non-toxic deep red emmission, and large Stokes shift properties. In the paper ZnCuInS/ZnSe/ZnS core/shell quantum dots were prepared with the particle size of 4.5nm. According to the measurement of photoluminescence spectrum emitted by ZnCuInS/ZnSe/ZnS core/shell quantum dots, the emitting peak of 700 nm and the full was achieved as red emitter.It was found that absorption edge and photoluminescence peak shifted to shorter wavelength with decreasing the nanocrystal size due to quantum size effect.Meanwhile, we were prepared ZnCuInS/ZnSe/ZnS core/shell quantum dot light emitting diodes and their photoluminescence properties were studied. After the suitable bias was applied on the films, increasing the ZnCuInS/ZnSe/ZnS QDs concentration in the blue GaN chips, red emission increased with decreasing LED’s blue light.

ELECTRON STRUCTURE INVESTIGATIONS OF InGaP/GaAs(100) HETEROSTRUCTURES WITH InP QUANTUM DOTS

2007 ◽  
Vol 06 (03n04) ◽  
pp. 215-219
Author(s):  
E. P. DOMASHEVSKAYA ◽  
V. A. TEREKHOV ◽  
V. M. KASHKAROV ◽  
S. YU. TURISHCHEV ◽  
S. L. MOLODTSOV ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Emission Spectra ◽  
Luminescence Spectra ◽  
Partial Density ◽  
Edge Structure ◽  
X Ray ◽  
Metal Organic ◽  
Structure Investigations ◽  
First Time ◽  
Inp Quantum Dots

Ultrasoft X-ray emission spectra (USXES) and X-ray absorption near-edge structure (XANES) spectra with the use of synchrotron radiation in the range of P L2,3-edges were obtained for the first time for nanostructures with InP quantum dots grown on GaAs 〈100〉 substrates by vapor-phase epitaxy from metal–organic compounds. These spectra represent local partial density of states in the valence and conduction bands. The additional XANES peak is detected; its intensity depends on the number of monolayers forming quantum dots. Assumptions are made on the band-to-band origin of luminescence spectra in the studied nanostructures.

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