Effect of Ligand Exchange on the Stability and Optical Properties of CdSe Quantum Dots

2007 ◽  
Vol 1056 ◽  
Author(s):  
Jacqueline T. Siy ◽  
Lindsay Leone ◽  
Michael H. Bartl
Keyword(s):  
Quantum Dots ◽  
Ligand Exchange ◽  
Size Reduction ◽  
Fine Tuning ◽  
Nanocrystal Quantum Dots ◽  
The Stability ◽  
Post Synthesis ◽  
Control Of Parameters ◽  
Amine Ligand ◽  
Solvent Volume

ABSTRACTA new post-synthesis heat/ligand-exchange treatment on CdSe nanocrystal quantum dots that allows fine-tuning the quantum dots size without losing important properties (e.g. photoluminescence) is presented. The careful control of parameters such as the reaction temperature, the quantum dot to alkyl-amine ligand mole ratio and the solvent volume is shown to provide tunable size reduction of the nanocrystals. This size reduction phenomenon provides new insights into the surface chemistry and stability of nanocrystals and can serve as a platform for designing, controlling and processing nanomaterials with tailored properties.

scholarly journals Novel post-synthesis purification strategies and the ligand exchange processes in simplifying the fabrication of PbS quantum dot solar cells

RSC Advances ◽  
2020 ◽  
Vol 10 (51) ◽  
pp. 30707-30715
Author(s):  
Anju Elsa Tom ◽  
Ajith Thomas ◽  
V. V. Ison
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Quantum Dot ◽  
Ligand Exchange ◽  
Quantum Dot Solar Cells ◽  
Exchange Processes ◽  
Post Synthesis ◽  
Pbs Quantum Dot

Quantum dots (QDs) solids with iodide passivation are a key component for most of the well-performing PbS QDs solar cells.

scholarly journals Near‐Infrared Active Lead Chalcogenide Quantum Dots: Preparation, Post‐Synthesis Ligand Exchange, and Applications in Solar Cells

2019 ◽  
Vol 58 (16) ◽  
pp. 5202-5224 ◽  
Author(s):  
Aabhash Shrestha ◽  
Munkhbayar Batmunkh ◽  
Antonio Tricoli ◽  
Shi Zhang Qiao ◽  
Sheng Dai
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Ligand Exchange ◽  
Near Infrared ◽  
Lead Chalcogenide ◽  
Post Synthesis

Armor-Like Passivated CsPbBr3 Quantum Dots: Boosted Stability with Hand-in-Hand Ligands and Enhanced Performance of Nuclear Battery

2021 ◽  
Author(s):  
Haibo Zeng ◽  
Dandan Yang ◽  
Zhiheng Xu ◽  
Chunhui Gong ◽  
Xiaoming Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Inorganic Perovskite ◽  
Surface Ligands ◽  
Perovskite Quantum Dots ◽  
Stability Issue ◽  
The Stability ◽  
Nuclear Battery ◽  
Cspbbr3 Quantum Dots

One of the main reasons for the stability issue of inorganic perovskite quantum dots (PQDs) is the fragile protection of surface ligands. Here, an armor-like passivation strategy is proposed to...

scholarly journals Hot-Wire Laser-Directed Energy Deposition: Process Characteristics and Benefits of Resistive Pre-Heating of the Feedstock Wire

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 634
Author(s):  
Agnieszka Kisielewicz ◽  
Karthikeyan Thalavai Pandian ◽  
Daniel Sthen ◽  
Petter Hagqvist ◽  
Maria Asuncion Valiente Bermejo ◽  
...  
Keyword(s):  
Heat Input ◽  
Energy Deposition ◽  
Fine Tuning ◽  
Hot Wire ◽  
Process Stability ◽  
Electrical Signals ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Directed Energy ◽  
The Stability

This study investigates the influence of resistive pre-heating of the feedstock wire (here called hot-wire) on the stability of laser-directed energy deposition of Duplex stainless steel. Data acquired online during depositions as well as metallographic investigations revealed the process characteristic and its stability window. The online data, such as electrical signals in the pre-heating circuit and images captured from side-view of the process interaction zone gave insight on the metal transfer between the molten wire and the melt pool. The results show that the characteristics of the process, like laser-wire and wire-melt pool interaction, vary depending on the level of the wire pre-heating. In addition, application of two independent energy sources, laser beam and electrical power, allows fine-tuning of the heat input and increases penetration depth, with little influence on the height and width of the beads. This allows for better process stability as well as elimination of lack of fusion defects. Electrical signals measured in the hot-wire circuit indicate the process stability such that the resistive pre-heating can be used for in-process monitoring. The conclusion is that the resistive pre-heating gives additional means for controlling the stability and the heat input of the laser-directed energy deposition.

In situ ligand exchange of thiol-capped CuInS2/ZnS quantum dots at growth stage without affecting luminescent characteristics

2011 ◽  
Vol 363 (2) ◽  
pp. 703-706 ◽  
Author(s):  
Hyunki Kim ◽  
Minwon Suh ◽  
Byung-Hwa Kwon ◽  
Dong Seon Jang ◽  
Sung Wook Kim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ligand Exchange ◽  
Growth Stage

Study on the characteristics of secondary arc current of UHV high compensation degree TCSC line under the fine-tuning mode

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Baina He ◽  
Yadi Xie ◽  
Jingru Zhang ◽  
Nirmal-Kumar C. Nair ◽  
Xingmin He ◽  
...  
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Stability Margin ◽  
Transmission Capacity ◽  
Fine Tuning ◽  
Series Compensation ◽  
Arc Current ◽  
Compensation Device ◽  
The Stability ◽  
Recovery Voltage

Abstract In the transmission line, the series compensation device is often used to improve the transmission capacity. However, when the fixed series capacitor (FSC) is used in high compensation series compensation device, the stability margin cannot meet the requirements. Therefore, thyristor controlled series compensator (TCSC) is often installed in transmission lines to improve the transmission capacity of the line and the stability of the system. For cost considerations, the hybrid compensation mode of FSC and TCSC is often adopted. However, when a single-phase grounding fault occurs in a transmission line with increased series compensation degree, the unreasonable distribution of FSC and TCSC will lead to the excessive amplitude of secondary arc current, which is not conducive to rapid arc extinguishing. To solve this problem, this paper is based on 1000 kV Changzhi-Nanyang-Jingmen UHV series compensation transmission system, using PSCAD simulation program to established UHV series compensation simulation model, The variation law of secondary arc current and recovery voltage during operation in fine tuning mode after adding TCSC to UHV transmission line is analyzed, and the effect of increasing series compensation degree on secondary arc current and recovery voltage characteristics is studied. And analyze the secondary arc current and recovery voltage when using different FSC and TCSC series compensation degree schemes, and get the most reasonable series compensation configuration scheme. The results show that TCSC compensation is more beneficial to arc extinguishing under the same series compensation. Compared with several series compensation schemes, it is found that with the increase of the proportion of TCSC, the amplitude of secondary arc current and recovery voltage vary greatly. Considering various factors, the scheme that is more conducive to accelerating arc extinguishing is chosen.

The possibility of a stable flat dark energy-dominated Swiss-cheese brane-world universe

2020 ◽  
Vol 17 (05) ◽  
pp. 2050075
Author(s):  
Nasr Ahmed ◽  
Kazuharu Bamba ◽  
F. Salama
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Cosmological Models ◽  
Brane World ◽  
Fine Tuning ◽  
Energy Conditions ◽  
Late Time ◽  
Swiss Cheese ◽  
Black Strings ◽  
The Stability

In this paper, we study the possibility of obtaining a stable flat dark energy-dominated universe in a good agreement with observations in the framework of Swiss-cheese brane-world cosmology. Two different brane-world cosmologies with black strings have been introduced for any cosmological constant [Formula: see text] using two empirical forms of the scale factor. In both models, we have performed a fine-tuning between the brane tension and the cosmological constant so that the Equation of state (EoS) parameter [Formula: see text] for the current epoch, where the redshift [Formula: see text]. We then used these fine–tuned values to calculate and plot all parameters and energy conditions. The deceleration–acceleration cosmic transition is allowed in both models, and the jerk parameter [Formula: see text] at late-times. Both solutions predict a future dark energy-dominated universe in which [Formula: see text] with no crossing to the phantom divide line. While the pressure in the first solution is always negative, the second solution predicts a better behavior of cosmic pressure where the pressure is negative only in the late-time accelerating era but positive in the early-time decelerating era. Such a positive-to-negative transition in the evolution of pressure helps to explain the cosmic deceleration–acceleration transition. Since black strings have been proved to be unstable by some authors, this instability can actually reflect doubts on the stability of cosmological models with black strings (Swiss-cheese type brane-worlds cosmological models). For this reason, we have carefully investigated the stability through energy conditions and sound speed. Because of the presence of quadratic energy terms in Swiss-cheese type brane-world cosmology, we have tested the new nonlinear energy conditions in addition to the classical energy conditions. We have also found that a negative tension brane is not allowed in both models of the current work as the energy density will no longer be well defined.

scholarly journals Effective replacement of cetyltrimethylammonium bromide (CTAB) by mercaptoalkanoic acids on gold nanorod (AuNR) surfaces in aqueous solutions

Nanoscale ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 658-668 ◽  
Author(s):  
Rafael del Caño ◽  
Jose M. Gisbert-González ◽  
Jose González-Rodríguez ◽  
Guadalupe Sánchez-Obrero ◽  
Rafael Madueño ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Gold Nanorods ◽  
Ligand Exchange ◽  
Cetyltrimethylammonium Bromide ◽  
Gold Nanorod ◽  
Experimental Conditions ◽  
Seed Mediated ◽  
The Stability

The highly packed cetyltrimethylammonium bromide bilayer on the surface of gold nanorods synthesized by the seed-mediated procedure hampers the complete ligand exchange under experimental conditions that preserves the stability of the dispersions.

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