Mn2+ ion influenced optical and photocatalytic behaviour of Mn–ZnS quantum dots prepared by a microwave assisted technique

RSC Advances ◽  
2014 ◽  
Vol 4 (84) ◽  
pp. 44592-44599 ◽  
Author(s):  
S. Joicy ◽  
R. Saravanan ◽  
D. Prabhu ◽  
N. Ponpandian ◽  
P. Thangadurai
Keyword(s):  
Quantum Dots ◽  
Light Emission ◽  
Blue Emission ◽  
Photon Absorption ◽  
Electron Trapping ◽  
Microwave Assisted ◽  
Orange Emission ◽  
Interstitial Zinc ◽  
Sulfur Emission ◽  
Emission Quenching

(a) Photon absorption and exciton formation, (b) interstitial sulfur emission, (c) interstitial zinc emission, (d) blue emission, (e) electron trapping by Mn ions' d state, (f) orange light emission and (g) orange emission quenching by electrons trapped by the neighbouring Mn2+ ions.

A facile and rapid approach to synthesize uric acid-capped Ti3C2 MXene quantum dots for the sensitive determination of 2,4,6-trinitrophenol both on surfaces and in solution

2020 ◽  
Vol 8 (47) ◽  
pp. 10837-10844
Author(s):  
Xin Wang ◽  
Xiaodan Zhang ◽  
Haiyan Cao ◽  
Yuming Huang
Keyword(s):  
Quantum Dots ◽  
Uric Acid ◽  
Blue Light ◽  
Light Emission ◽  
Blue Light Emission ◽  
Microwave Assisted ◽  
Sensitive Determination ◽  
Microwave Assisted Method

The UA@Ti3C2 QDs with blue light emission were synthesized by a simple and green microwave-assisted method, and used as a sensitive and selective probe for the detection of TNP both on surfaces and in solution.

scholarly journals Fabrication and Characterization of a Light-Emitting Device Based on the CdS/ZnS Spherical Quantum Dots

2021 ◽  
Author(s):  
Kobra Hasanirokh ◽  
Asghar Asgari ◽  
Saber Mohammadi
Keyword(s):  
Quantum Dots ◽  
Current Density ◽  
White Light ◽  
Light Emission ◽  
Blue Emission ◽  
Critical Factor ◽  
White Light Emission ◽  
Device Structure ◽  
Light Emitting ◽  
Particle Layer

Abstract In 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 ITO/ ZnO / QD / CBP/ MoO 3 / 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 get the red shifted as the dot size increases. Furthermore, this QD-LED with a smaller nano particle layer has a higher current density.

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.

scholarly journals A Facile Microwave-Assisted Hydrothermal Synthesis of Graphene Quantum Dots for Organic Solar Cell Efficiency Improvement

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Thi Thu Hoang ◽  
Hoai Phuong Pham ◽  
Quang Trung Tran
Keyword(s):  
Quantum Dots ◽  
Organic Solar Cells ◽  
Energy Levels ◽  
Graphene Quantum Dots ◽  
Blue Emission ◽  
Spectroscopic Characterization ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Microwave Assisted

Carbon-based nanomaterials have successively remained at the forefront of different research fields and applications for years. Understanding of low-dimension carbon material family (CNT, fullerenes, graphene, and graphene quantum dots) has arrived at a certain extension. In this report, graphene quantum dots were synthesized from graphene oxide with a microwave-assisted hydrothermal method. Compared with conventional time-consuming hydrothermal routes, this novel method requires a much shorter time, around ten minutes. Successful formation of quantum dots derived from graphene sheets was verified with microscopic and spectroscopic characterization. Nanoparticles present a diameter of about 2-8 nm, blue emission under ultraviolet excitation, and good dispersion in polar solvents and can be collected in powder form. The synthesized graphene quantum dots were utilized as a hole transport layer in organic solar cells to enhance the cell quantum efficiency. Such quantum dots possess energy levels (Ec and Ev) relevant to HOMO and LUMO levels of conductive polymers. Mixing P3HT:PCBM polymer and graphene quantum dots of sufficient extent notably helps reduce potential difference at interfaces of the two materials. Overall efficiency consequently advances to 1.43%, an increase of more than 44% compared with pristine cells (0.99%).

Yellowish and blue luminescent graphene oxide quantum dots prepared via a microwave-assisted hydrothermal route using H2O2 and KMnO4 as oxidizing agents

2018 ◽  
Vol 42 (6) ◽  
pp. 3999-4007 ◽  
Author(s):  
Chechia Hu ◽  
Tzer-Rurng Su ◽  
Tzu-Jen Lin ◽  
Chien-Wei Chang ◽  
Kuo-Lun Tung
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Blue Light ◽  
Light Emission ◽  
Quantum Yields ◽  
Hydrothermal Route ◽  
Blue Light Emission ◽  
Oxidizing Agents ◽  
Microwave Assisted ◽  
Graphene Oxide Quantum Dots

Microwave-assisted hydrothermal synthesized GOQDs exhibit yellowish-green and blue light emission with quantum yields of 15.1% and 8.4%, respectively.

InAs/InGaAs quantum dots confined by InAlAs barriers for enhanced room temperature light emission: Photoelectric properties and deep levels

2021 ◽  
Vol 238 ◽  
pp. 111514
Author(s):  
Sergii Golovynskyi ◽  
Oleksandr I. Datsenko ◽  
Luca Seravalli ◽  
Giovanna Trevisi ◽  
Paola Frigeri ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Room Temperature ◽  
Light Emission ◽  
Deep Levels ◽  
Photoelectric Properties
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