(Invited) Impact of Boron Doping and H2 Annealing on Light Emission from Ge/Si Core-Shell Quantum Dots

2021 ◽  
Vol 104 (4) ◽  
pp. 105-112
Author(s):  
Seiichi Miyazaki ◽  
Katsunori Makihara
Keyword(s):  
Quantum Dots ◽  
Light Emission ◽  
Boron Doping ◽  
Core Shell

scholarly journals Fabrication of a light-emitting device based on the CdS/ZnS spherical quantum dots

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Kobra Hasanirokh ◽  
Asghar Asgari ◽  
Saber Mohammadi
Keyword(s):  
Quantum Dots ◽  
Current Density ◽  
White Light ◽  
Light Emission ◽  
Blue Emission ◽  
White Light Emission ◽  
Core Shell ◽  
Device Structure ◽  
Light Emitting ◽  
Particle Layer

AbstractIn this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process. These four-layer quantum well quantum dots (QWQDs) can generate the white light emission. The positional design of different layers i.e., core/shell QD emitters is a critical factor for white emissive devices. The blue emission generated by CdS core mixes with green/orange components originating from ZnS inner shell and creates an efficiency white light emission. Then, we fabricate a white-QDLED with a device structure of FTO/ ZnO / QD / CBP/ MoO3 / Al films. A thin film of CdS/ZnS/CdS/ZnS QDs is deposited by electrostatically assembled colloidal QD solutions. The experimental results show that the emission spectra of QDs and current density through the LED are controlled by varying the particle sizes. The peaks of absorbance and Photoluminescence (PL) spectrums for core/shell structures get the red shifted as the dot size increases. Furthermore, this QD-LED with a smaller nano particle layer has a higher current density.

Zinc quinolate complex decorated CuInS2/ZnS core/shell quantum dots for white light emission

2017 ◽  
Vol 5 (29) ◽  
pp. 7291-7296 ◽  
Author(s):  
Sabyasachi Pramanik ◽  
Satyapriya Bhandari ◽  
Arun Chattopadhyay
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Light Emission ◽  
White Light Emission ◽  
Core Shell ◽  
Light Emitting

Formation of a zinc-quinolate complex on the surface of CuInS2/ZnS core shell quantum dots leading to the fabrication of an advanced white light emitting nanocomposite.

scholarly journals Tunable light emission by exciplex state formation between hybrid halide perovskite and core/shell quantum dots: Implications in advanced LEDs and photovoltaics

2016 ◽  
Vol 2 (1) ◽  
pp. e1501104 ◽  
Author(s):  
Rafael S. Sanchez ◽  
Mauricio Solis de la Fuente ◽  
Isaac Suarez ◽  
Guillermo Muñoz-Matutano ◽  
Juan P. Martinez-Pastor ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Light Emission ◽  
Mixed System ◽  
Core Shell ◽  
Carrier Injection ◽  
Intermediate Band ◽  
Light Emitting ◽  
Exciplex Emission ◽  
Halide Perovskite

We report the first observation of exciplex state electroluminescence due to carrier injection between the hybrid lead halide perovskite (MAPbI3–xClx) and quantum dots (core/shell PbS/CdS). Single layers of perovskite (PS) and quantum dots (QDs) have been produced by solution processing methods, and their photoluminescent properties are compared to those of bilayer samples in both PS/QD and QD/PS configurations. Exciplex emission at lower energies than the band gap of both PS and QD has been detected. The exciplex emission wavelength of this mixed system can be simply tuned by controlling the QD size. Light-emitting diodes (LEDs) have been fabricated using those configurations, which provide light emission with considerably low turn-on potential. The “color” of the LED can also be tuned by controlling the applied bias. The presence of the exciplex state PS and QDs opens up a broad range of possibilities with important implications not only in tunable LEDs but also in the preparation of intermediate band gap photovoltaic devices with the potentiality of surpassing the Shockley-Queisser limit.

High-Temperature Synthesis of CdSe-Based Core/Shell, Core/Shell/Shell, and Core/Graded-Shell Nanoplatelets for Stable and Efficient Narrowband Emitters

2019 ◽  
Author(s):  
Aurelio A. Rossinelli ◽  
Henar Rojo ◽  
Aniket S. Mule ◽  
Marianne Aellen ◽  
Ario Cocina ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Temperature ◽  
Equilibrium Shape ◽  
Size Variation ◽  
Crystal Defects ◽  
Atomic Scale ◽  
Quantum Yields ◽  
Core Shell ◽  
Compositional Gradient ◽  
High Quality

<div>Colloidal semiconductor nanoplatelets exhibit exceptionally narrow photoluminescence spectra. This occurs because samples can be synthesized in which all nanoplatelets share the same atomic-scale thickness. As this dimension sets the emission wavelength, inhomogeneous linewidth broadening due to size variation, which is always present in samples of quasi-spherical nanocrystals (quantum dots), is essentially eliminated. Nanoplatelets thus offer improved, spectrally pure emitters for various applications. Unfortunately, due to their non-equilibrium shape, nanoplatelets also suffer from low photo-, chemical, and thermal stability, which limits their use. Moreover, their poor stability hampers the development of efficient synthesis protocols for adding high-quality protective inorganic shells, which are well known to improve the performance of quantum dots. <br></div><div>Herein, we report a general synthesis approach to highly emissive and stable core/shell nanoplatelets with various shell compositions, including CdSe/ZnS, CdSe/CdS/ZnS, CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S, and CdSe/ZnSe. Motivated by previous work on quantum dots, we find that slow, high-temperature growth of shells containing a compositional gradient reduces strain-induced crystal defects and minimizes the emission linewidth while maintaining good surface passivation and nanocrystal uniformity. Indeed, our best core/shell nanoplatelets (CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S) show photoluminescence quantum yields of 90% with linewidths as low as 56 meV (19.5 nm at 655 nm). To confirm the high quality of our different core/shell nanoplatelets for a specific application, we demonstrate their use as gain media in low-threshold ring lasers. More generally, the ability of our synthesis protocol to engineer high-quality shells can help further improve nanoplatelets for optoelectronic devices.</div>

Enhanced Photocurrent Generation in Proton‐Irradiated “Giant” CdSe/CdS Core/Shell Quantum Dots

2019 ◽  
Vol 29 (46) ◽  
pp. 1904501 ◽  
Author(s):  
Chao Wang ◽  
David Barba ◽  
Gurpreet S. Selopal ◽  
Haiguang Zhao ◽  
Jiabin Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Core Shell ◽  
Photocurrent Generation

Surface Organic Ligands-Passivated Quantum Dots: Toward High-Performance Light-Emitting Diodes with Long Lifetime

2021 ◽  
Author(s):  
Lishuang Wang ◽  
Ying Lv ◽  
Jie Lin ◽  
Jialong Zhao ◽  
Xingyuan Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Organic Ligands ◽  
Colloidal Quantum Dots ◽  
Core Shell ◽  
Light Emitting ◽  
Long Lifetime

For quantum dots light-emitting diodes (QLEDs), typical colloidal quantum dots (QDs) are usually composed of a core/shell heterostructure which is covered with organic ligands as surface passivated materials to confine...

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