Colloidal Synthesis and Properties of InAs/InP and InAs/CdSe Core/Shell Nanocrystals

1999 ◽  
Vol 571 ◽  
Author(s):  
Yun-Wei Cao ◽  
Julia Aksenton ◽  
Victor Soloviev ◽  
Uri Banin
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Photoelectron Spectroscopy ◽  
Shell Growth ◽  
Band Gap Energy ◽  
Colloidal Synthesis ◽  
Core Shell ◽  
Cdse Core ◽  
X Ray ◽  
Photoluminescence Quantum Yield

ABSTRACTHigh-temperature colloidal synthesis of InAs/InP and InAs/CdSe core/shell nanocrystal quantum dots is reported. InP and CdSe shells with several thicknesses were grown on InAs cores ranging in diameter between 20 to 50 Å. Optical spectra, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to analyze the core/shell quantum dots and determine their chemical composition, average size, size distributions, and structures. The experimental results indicate that shell growth is uniform, expitaxial, and controllable. For both InP and CdSe shells, growth is accompanied by a red shift of the band gap energy as a result of the extension of the electron wavefunction into the shell region. An increase of the room temperature photoluminescence quantum yield by a factor of∼4 is observed with CdSe shell growth on InAs Cores. The growth of InP shells, however, quenches the photoluminescence quantum yield. The difference is assigned to outer surface effects in core/shell nanocrystals.

scholarly journals Combining HR-TEM and XPS to elucidate the core–shell structure of ultrabright CdSe/CdS semiconductor quantum dots

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Florian Weigert ◽  
Anja Müller ◽  
Ines Häusler ◽  
Daniel Geißler ◽  
Dieter Skroblin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Photoelectron Spectroscopy ◽  
Surface Passivation ◽  
Semiconductor Quantum Dots ◽  
Optical Measurements ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
X Ray ◽  
The Core

AbstractControlling thickness and tightness of surface passivation shells is crucial for many applications of core–shell nanoparticles (NP). Usually, to determine shell thickness, core and core/shell particle are measured individually requiring the availability of both nanoobjects. This is often not fulfilled for functional nanomaterials such as many photoluminescent semiconductor quantum dots (QD) used for bioimaging, solid state lighting, and display technologies as the core does not show the application-relevant functionality like a high photoluminescence (PL) quantum yield, calling for a whole nanoobject approach. By combining high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS), a novel whole nanoobject approach is developed representatively for an ultrabright oleic acid-stabilized, thick shell CdSe/CdS QD with a PL quantum yield close to unity. The size of this spectroscopically assessed QD, is in the range of the information depth of usual laboratory XPS. Information on particle size and monodispersity were validated with dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) and compared to data derived from optical measurements. In addition to demonstrating the potential of this novel whole nanoobject approach for determining architectures of small nanoparticles, the presented results also highlight challenges faced by different sizing and structural analysis methods and method-inherent uncertainties.

Enhancement Mechanism of the Photoluminescence Quantum Yield in Highly Efficient ZnS–AgIn5S8 Quantum Dots with Core/Shell Structures

2018 ◽  
Vol 122 (18) ◽  
pp. 10125-10132 ◽  
Author(s):  
Seonghyun Jeong ◽  
Soyeon Yoon ◽  
So Yeon Chun ◽  
Hee Chang Yoon ◽  
Noh Soo Han ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Shell Structures ◽  
Core Shell ◽  
Enhancement Mechanism ◽  
Highly Efficient ◽  
Photoluminescence Quantum Yield

Synthesis and Characterization of Highly Luminescent (CdSe)ZnS Quantum Dots

1996 ◽  
Vol 452 ◽  
Author(s):  
F. V. Mikulec ◽  
B. O. Dabbousi ◽  
J. Rodriguez-Viejo ◽  
J. R. Heine ◽  
H. Mattoussi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Photoelectron Spectroscopy ◽  
Red Light ◽  
Visible Region ◽  
Closed Shell ◽  
X Ray ◽  
Transmission Electron ◽  
Organometallic Precursors ◽  
The Many

AbstractWe report the synthesis of a series of nearly monodisperse ZnS-overcoated CdSe quantum dots whose room temperature photoluminescence quantum yield approaches 50%. This spectrally narrow (FWHM < 40nm) band edge luminescence spans the visible region from blue to red light. We use a two-step synthesis based on the high temperature decomposition of organometallic precursors in a coordinating solvent. We characterize our composite quantum dots using optical spectroscopies, wavelength dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, high resolution transmission electron microscopy, small angle x-ray scattering, and wide angle x-ray diffraction. The data indicate that samples displaying the highest quantum yield are those which have just achieved a closed shell of ZnS encapsulating the CdSe core. As more ZnS is added, the quantum yield decreases somewhat, possibly due to the many defects present in larger ZnS shells.

Excitation Energy Dependence of the Photoluminescence Quantum Yield of Core/Shell CdSe/CdS Quantum Dots and Correlation with Circular Dichroism

2018 ◽  
Vol 30 (2) ◽  
pp. 465-471 ◽  
Author(s):  
Irina V. Martynenko ◽  
Anvar S. Baimuratov ◽  
Victoria A. Osipova ◽  
Vera A. Kuznetsova ◽  
Finn Purcell-Milton ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Circular Dichroism ◽  
Quantum Yield ◽  
Excitation Energy ◽  
Energy Dependence ◽  
Core Shell ◽  
Cds Quantum Dots ◽  
Photoluminescence Quantum Yield ◽  
Circular Dichroïsm

Highly luminescent, off-stoichiometric CuxInyS2/ZnS quantum dots for near-infrared fluorescence bio-imaging

RSC Advances ◽  
2015 ◽  
Vol 5 (54) ◽  
pp. 43449-43455 ◽  
Author(s):  
Hyung Seok Choi ◽  
Youngsun Kim ◽  
Jae Chul Park ◽  
Mi Hwa Oh ◽  
Duk Young Jeon ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Zinc Sulfide ◽  
Near Infrared ◽  
Core Shell ◽  
Near Infrared Fluorescence ◽  
Photoluminescence Quantum Yield ◽  
Copper Indium ◽  
Bio Imaging ◽  
Heating Up

We synthesized highly luminescent, NIR-emitting copper–indium–sulfur/zinc sulfide (CIS/ZnS) core–shell QDs with a high photoluminescence quantum yield (about 60%) using a heating up method.

Thin-shell CdSe/ZnCdS core/shell quantum dots and their electroluminescent device application

2018 ◽  
Vol 6 (41) ◽  
pp. 11104-11110 ◽  
Author(s):  
Song Wei ◽  
Yue Liu ◽  
Mingyue Ma ◽  
Yao Wu ◽  
Lijian Huang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Quantum Dot ◽  
Current Efficiency ◽  
Thin Shell ◽  
Light Emitting Diode ◽  
Core Shell ◽  
Light Emitting ◽  
Photoluminescence Quantum Yield ◽  
A Current

Thin-shell CdSe/2CdS0.5Zn0.5S core/shell quantum dots with a photoluminescence quantum yield of 82% were synthesized. A quantum dot light emitting diode with a current efficiency of 12.5 cd A−1was fabricated.

scholarly journals Engineering Sr-doping for enabling long-term stable FAPb1−xSrxI3 quantum dots with 100% photoluminescence quantum yield

2021 ◽  
Vol 9 (5) ◽  
pp. 1555-1566
Author(s):  
Andrés F. Gualdrón-Reyes ◽  
David F. Macias-Pinilla ◽  
Sofia Masi ◽  
Carlos Echeverría-Arrondo ◽  
Said Agouram ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Toxic Metals ◽  
Environmentally Friendly ◽  
Photoluminescence Quantum Yield ◽  
Improved Performance ◽  
Pb Substitution

The Pb substitution in quantum dots (PQDs) with lesser toxic metals has been widely searched to be environmentally friendly, and be of comparable or improved performance compared to the lead-perovskite.

Poly(Vinylidene Fluoride)-Passivated CsPbBr3 Perovskite Quantum Dots with Near-Unity Photoluminescence Quantum Yield and Superior Stability

2021 ◽  
Author(s):  
Lin Yang ◽  
Bowen Fu ◽  
Xu Li ◽  
Hao Chen ◽  
Lili Li
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Vinylidene Fluoride ◽  
Excellent Performance ◽  
Inorganic Perovskite ◽  
Photoluminescence Quantum Yield ◽  
Poly Vinylidene Fluoride ◽  
Perovskite Quantum Dots ◽  
Optoelectronic Applications ◽  
Pl Quenching

All inorganic perovskite quantum dots (QDs) have received great attention owing to their excellent performance in optoelectronic applications. However, they often suffer from the defect-related photoluminescence (PL) quenching and phase...

scholarly journals Chemical in‐depth analysis of (Ca/Sr)F 2 core–shell like nanoparticles by X‐ray photoelectron spectroscopy with tunable excitation energy

2021 ◽  
Vol 53 (5) ◽  
pp. 494-508
Author(s):  
Anja Müller ◽  
Thoralf Krahl ◽  
Jörg Radnik ◽  
Andreas Wagner ◽  
Carsten Kreyenschulte ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Photoelectron Spectroscopy ◽  
Core Shell ◽  
X Ray ◽  
Depth Analysis
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