Directional quantum dot emission by soft-stamping on silicon Mie resonators

For the first time ever cyclohexeno-1,2,3-selenadiazole (SDZ) has been employed for the synthesis of core–shell ZnSe–CdSe quantum dots thus promoting an eco-friendly and reasonably less toxic synthesis method for such quantum dot hetero-structures.

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Structure evolution from CdSSe alloy to CdS/CdSe core/shell for Cd(S, Se) composite quantum dots and its impact on the performance of sensitized solar cell

Dalton Transactions ◽

10.1039/d1dt02061g ◽

2021 ◽

Author(s):

Junfei Fang ◽

Wenlei Lv ◽

Yilong Lei ◽

Jianping Deng ◽

Pengchao Zhang ◽

...

Keyword(s):

Quantum Dots ◽

Solar Cell ◽

Quantum Dot ◽

Structure Evolution ◽

Core Shell ◽

Cdse Core

CdSSe alloy and CdS/CdSe core/shell quantum dots (QDs) are widely studied in quantum dot solar cell (QDSSCs). However, up to date, there have been no detailed comparative investigations on the cell...

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Internal Atomic-Scale Structure Determination and Band Alignment of II-VI Quantum Dot Heterostructures

10.26434/chemrxiv.11349713.v1 ◽

2019 ◽

Author(s):

Cecilia Gentle ◽

Yuanheng Wang ◽

Tyler N. Haddock ◽

Conner P. Dykstra ◽

Renske M. van der Veen

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Absorption Spectroscopy ◽

Shell Structure ◽

Electronic Band Structure ◽

Band Alignment ◽

Atomic Scale ◽

Core Shell ◽

Cdse Core ◽

Electronic Band

This work shows that ZnTe/CdSe core/shell quantum dots synthesized by standard literature procedures in actuality have an alloyed CdxZn1-xTe core. We employ X-ray absorption spectroscopy (XAS) at all four K-shell ionization edges (Zn, Te, Cd, Se) and perform a global fitting analysis in order to extract the first-shell bond distances. We combine our XAS results with transmission electron microscopy (TEM) sizing and elemental analyses, which allows us to propose models of the internal particle structure. Our multimodal characterization approach confirms (1) the presence of Cd-Te bonds, (2) cation alloying in the particle core (and the absence of anion alloying), and (3) a patchy pure-phase CdSe shell. We synthesize particles of different shell thicknesses and performed synthetic control studies that allowed us to discard a ZnTe/CdTe/CdSe core/shell/shell structure and confirm the alloyed core/shell structure. Our structural analysis is extended with electronic band structure calculations and UV/vis absorption spectroscopy, demonstrating that the alloyed CdxZn1-xTe/CdSe core/shell quantum dots exhibit a direct band gap, different from the predicted type-II band alignment of the intended ZnTe/CdSe core/shell quantum dots. This study highlights the challenges with synthesizing II-VI quantum dot heterostructures and the power of XAS for understanding the internal structure of heterogenous nanoparticles.

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Internal Atomic-Scale Structure Determination and Band Alignment of II-VI Quantum Dot Heterostructures

10.26434/chemrxiv.11349713 ◽

2019 ◽

Author(s):

Cecilia Gentle ◽

Yuanheng Wang ◽

Tyler N. Haddock ◽

Conner P. Dykstra ◽

Renske M. van der Veen

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Absorption Spectroscopy ◽

Shell Structure ◽

Electronic Band Structure ◽

Band Alignment ◽

Atomic Scale ◽

Core Shell ◽

Cdse Core ◽

Electronic Band

This work shows that ZnTe/CdSe core/shell quantum dots synthesized by standard literature procedures in actuality have an alloyed CdxZn1-xTe core. We employ X-ray absorption spectroscopy (XAS) at all four K-shell ionization edges (Zn, Te, Cd, Se) and perform a global fitting analysis in order to extract the first-shell bond distances. We combine our XAS results with transmission electron microscopy (TEM) sizing and elemental analyses, which allows us to propose models of the internal particle structure. Our multimodal characterization approach confirms (1) the presence of Cd-Te bonds, (2) cation alloying in the particle core (and the absence of anion alloying), and (3) a patchy pure-phase CdSe shell. We synthesize particles of different shell thicknesses and performed synthetic control studies that allowed us to discard a ZnTe/CdTe/CdSe core/shell/shell structure and confirm the alloyed core/shell structure. Our structural analysis is extended with electronic band structure calculations and UV/vis absorption spectroscopy, demonstrating that the alloyed CdxZn1-xTe/CdSe core/shell quantum dots exhibit a direct band gap, different from the predicted type-II band alignment of the intended ZnTe/CdSe core/shell quantum dots. This study highlights the challenges with synthesizing II-VI quantum dot heterostructures and the power of XAS for understanding the internal structure of heterogenous nanoparticles.

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The Performance of Active Coated Nanoparticles Based on Quantum-Dot Gain Media

Advances in OptoElectronics ◽

10.1155/2012/368786 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 10

Author(s):

Sawyer D. Campbell ◽

Richard W. Ziolkowski

Keyword(s):

Quantum Dots ◽

Optical Properties ◽

Quantum Dot ◽

Relative Size ◽

Core Shell ◽

The Core ◽

Coated Nanoparticles ◽

Dot Gain ◽

Band Gap Structure ◽

Gain Media

Quantum-dots (QDs) provide an exciting option for the gain media incorporated in active coated nanoparticles (CNPs) because they possess large gain coefficients resulting from their extreme confinement effects. The optical properties of core/shell QDs can be tuned by changing the relative size of the core/shell, that is, by effectively changing its band gap structure. Similarly, the resonance of a CNP can be adjusted by changing the relative sizes of its layers. It is demonstrated here that by optimally locating the QDs inside a resonant CNP structure it is possible to greatly enhance the intrinsic amplifying behavior of the combined QD-CNP system.

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Effect of core quantum-dot size on power-conversion-efficiency for silicon solar-cells implementing energy-down-shift using CdSe/ZnS core/shell quantum dots

Nanoscale ◽

10.1039/c4nr02472a ◽

2014 ◽

Vol 6 (21) ◽

pp. 12524-12531 ◽

Cited By ~ 26

Author(s):

Seung-Wook Baek ◽

Jae-Hyoung Shim ◽

Hyun-Min Seung ◽

Gon-Sub Lee ◽

Jin-Pyo Hong ◽

...

Keyword(s):

Quantum Dots ◽

Solar Cells ◽

Quantum Dot ◽

Power Conversion Efficiency ◽

Conversion Efficiency ◽

Power Conversion ◽

Silicon Solar Cells ◽

Core Shell

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Color-tunable Ag-In-Zn-S quantum-dot light-emitting devices realizing green, yellow and amber emissions

Journal of Materials Chemistry C ◽

10.1039/c6tc04798j ◽

2017 ◽

Vol 5 (4) ◽

pp. 953-959 ◽

Cited By ~ 24

Author(s):

Dan Bi Choi ◽

Sohee Kim ◽

Hee Chang Yoon ◽

Minji Ko ◽

Heesun Yang ◽

...

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Light Emitting Diodes ◽

Core Shell ◽

Light Emitting ◽

Light Emitting Devices ◽

Standard Device ◽

Device Architecture ◽

Color Tunable ◽

The Creation

In this study, we report the creation of heterostructured alloy core/shell Ag-In-Zn-S (AIZS)/ZnS quantum dots (QDs) by sequential core-forming, alloying and shelling processes and the fabrication of color-tunable QD light-emitting diodes (QLEDs) with a standard device architecture.

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Drastic difference between hole and electron injection through the gradient shell of CdxSeyZn1−xS1−y quantum dots

Nanoscale ◽

10.1039/c7nr04495j ◽

2017 ◽

Vol 9 (34) ◽

pp. 12503-12508 ◽

Cited By ~ 3

Author(s):

Mohamed Abdellah ◽

Felipe Poulsen ◽

Qiushi Zhu ◽

Nan Zhu ◽

Karel Žídek ◽

...

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Fluorescence Spectroscopy ◽

Electron Injection ◽

Hole Injection ◽

Core Shell

Ultrafast fluorescence spectroscopy was used to investigate the hole injection in CdxSeyZn1−xS1−y gradient core–shell quantum dot sensitized NiO photocathodes.

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