scholarly journals Full-color-emitting (CuInS2)ZnS-alloyed core/shell quantum dots with trimethoxysilyl end-capped ligands soluble in an ionic liquid

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25576-25582 ◽  
Author(s):  
Huiqing Wang ◽  
Jiayuan Hu ◽  
Min Zhu ◽  
Yucheng Li ◽  
Hao Qian ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ionic Liquid ◽  
Blue Shift ◽  
Core Shell ◽  
Full Color ◽  
Pl Intensity

ZCIS QDs were fabricated by varying ratio stock A to stock B. PL intensity enhanced and blue shift as shell layers increase. Emissions covering 800 nm to 518 nm tuned by compositions or shell layers. Ligand exchanged by MPtMS enable solubility in IL.

Versatile surface-active ionic liquid: construction of microemulsions and their applications in light harvesting

2020 ◽  
Vol 22 (15) ◽  
pp. 8157-8163
Author(s):  
Krishnaiah Damarla ◽  
Sanjay Mehra ◽  
Pratap Bahadur ◽  
Debes Ray ◽  
V. K. Aswal ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ionic Liquid ◽  
Light Harvesting ◽  
Advanced Materials ◽  
Core Shell ◽  
Surface Active Ionic Liquid ◽  
Surface Active

This article outlines a sustainable method towards the synthesis of advanced materials such as core/shell Quantum Dots (QDs) and their in situ stabilization using microemulsions (MEs).

Effects of Low Energy Carbon Ion Implantation on the Material Properties of InAs/GaAs Quantum Dots with Variation in Capping Layer

2015 ◽  
Vol 1743 ◽  
Author(s):  
S. Upadhyay ◽  
A Mandal ◽  
A. Basu ◽  
P. Singh ◽  
S. Chakrabarti
Keyword(s):  
Quantum Dots ◽  
Ion Implantation ◽  
Blue Shift ◽  
Low Energy ◽  
Stress Generation ◽  
Carbon Ions ◽  
Implantation Energy ◽  
Carbon Ion ◽  
Capping Layer ◽  
Pl Intensity

ABSTRACTUnder controlled irradiation of low energy carbon ions, photoluminescence (PL) study of InAs quantum dots prepared with different capping structures (GaAs and InAlGaAs) was carried out. Samples were investigated by varying implantation energy from 15 keV to 50 keV with fluence ranging between 3 × 1011ions/cm2 and 8 × 1011 ions/cm2. For fixed fluence of 4 × 1011ions/cm2, low temperature PL showed enhancement in a certain range of energy, along with a blue shift in the PL peak wavelength. In contrast, with varying fluence at fixed implantation energy of 50 keV, PL enhancement was not significant, rather a drop in PL intensity was noted at higher fluence from 5 × 1011 to 8 × 1011 ions/cm2. Moreover, carbon ion implantation caused a blue shift in the PL emission peak for both energy and fluence variations. PL intensity suppression was possibly caused by the formation of non-radiative recombination centers (NRCs) near the capping layer, while the corresponding blue shift might be attributed to stress generation in the capping layer due to implantation. As-grown and implanted InAlGaAs capped samples did not exhibit much variation in full width at half maxima of PL spectra; however, significant variation was observed for the GaAs capped sample. These results validate that InAlGaAs-capped QDs are more immune to ion implantation.

Continuous Synthesis of Full-Color Emitting Core/Shell Quantum Dots via Microreaction

2009 ◽  
Vol 9 (11) ◽  
pp. 4807-4813 ◽  
Author(s):  
Hongwei Yang ◽  
Weiling Luan ◽  
Zhen Wan ◽  
Shan-tung Tu ◽  
Wei-Kang Yuan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Core Shell ◽  
Continuous Synthesis ◽  
Full Color

scholarly journals Synthesis of Zn-Cu-In-S/ZnS Core/Shell Quantum Dots with Inhibited Blue-Shift Photoluminescence and Applications for Tumor Targeted Bioimaging

Theranostics ◽  
2013 ◽  
Vol 3 (2) ◽  
pp. 99-108 ◽  
Author(s):  
Weisheng Guo ◽  
Na chen ◽  
Yu Tu ◽  
Chunhong Dong ◽  
Bingbo Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Blue Shift ◽  
Core Shell

scholarly journals Ge/Si core/shell quantum dots in alumina: tuning the optical absorption by the core and shell size

Nanophotonics ◽  
2017 ◽  
Vol 6 (5) ◽  
pp. 1055-1062 ◽  
Author(s):  
Nikolina Nekić ◽  
Jordi Sancho-Parramon ◽  
Ivančica Bogdanović-Radović ◽  
Jörg Grenzer ◽  
René Hübner ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Blue Shift ◽  
Core Shell ◽  
Shell Size ◽  
Experimental Realization ◽  
Sputtering Deposition ◽  
The Core ◽  
Theoretical Predictions ◽  
The Matrix

AbstractGe/Si core/shell quantum dots (QDs) recently received extensive attention due to their specific properties induced by the confinement effects of the core and shell structure. They have a type II confinement resulting in spatially separated charge carriers, the electronic structure strongly dependent on the core and shell size. Herein, the experimental realization of Ge/Si core/shell QDs with strongly tunable optical properties is demonstrated. QDs embedded in an amorphous alumina glass matrix are produced by simple magnetron sputtering deposition. In addition, they are regularly arranged within the matrix due to their self-assembled growth regime. QDs with different Ge core and Si shell sizes are made. These core/shell structures have a significantly stronger absorption compared to pure Ge QDs and a highly tunable absorption peak dependent on the size of the core and shell. The optical properties are in agreement with recent theoretical predictions showing the dramatic influence of the shell size on optical gap, resulting in 0.7 eV blue shift for only 0.4 nm decrease at the shell thickness. Therefore, these materials are very promising for light-harvesting applications.

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>

Dispersive Liquid-Liquid Microextraction Based on Ionic Liquid and Spectrophotometric Determination of Bilirubin in Biological Samples

2020 ◽  
Vol 16 (5) ◽  
pp. 652-659
Author(s):  
Asiye A. Avan ◽  
Hayati Filik
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Biological Samples ◽  
Urine Samples ◽  
Spectrophotometric Detection ◽  
Full Color ◽  
Dispersive Liquid Liquid Microextraction ◽  
Urine And Serum ◽  
Liquid Microextraction

Background: An Ionic Liquid-based based Dispersive Liquid-Liquid Microextraction (IL-DLLME) method was not applied to preconcentration and determination of bilirubin. Ionic Liquids (ILs) are new chemical compounds. In recent years, Ionic Liquids (ILs) have been employed as alternative solvents to toxic organic solvents. Due to these perfect properties, ILs have already been applied in many analytical extraction processes, presenting high extraction yield and selectivity for analytes. Methods: In this study, IL-DLLME was applied to biological samples (urine and serum) for the spectrophotometric detection of bilirubin. For bilirubin analysis, the full-color development was based on the reaction with periodate in the presence of hydrochloric acid. The high affinity of bilirubin for the ionic liquid phase gave extraction percentages above 98% in 0.3 M HCl solution. Results: Several IL-extraction parameters were optimized and room temperature ionic liquid 1-butyl- 1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and ethanol were used as extraction and disperser solution. The linear range was found in the range of 0.5-6.0 μM (0.3-3.5 μg mL-1) and the limits of detection of the proposed method was 0.5 μM (0.3 μg mL-1). The proposed method was applied for the preconcentration and separation of trace bilirubin in real urine samples. Also, the recoveries for bilirubin in spiked biological samples (urine and serum) were found to be acceptable, between 95-102%. Conclusion: The proposed IL-DLLMEapproach was employed for the enrichment and determination of trace levels of bilirubin in urine samples using NaIO4 as an oxidizing agent and Uv-vis spectrophotometric detection. The periodate oxidation of bilirubin is rapid, effective, selective, and simple to perform. The method contains only HCl, NaOI4, and an anionic surfactant. The method may be useful for economizing in the consumption of reagents in bilirubin determining. The IL-DLLMEmethod ensures a high yield and has a low toxicity no skin sensitization, no mutagenicity and no ecotoxicity in an aquatic environment since only very low quantities of an IL is required. For full-color formation, no any extra auxiliary reagents are required. Besides, the IL-DLLME technique uses a low-cost instrument such as Uv-vis which is present in most of the medical laboratories.

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