Robust DNA-Functionalized Core/Shell Quantum Dots with Fluorescent Emission Spanning from UV–vis to Near-IR and Compatible with DNA-Directed Self-Assembly

2012 ◽  
Vol 134 (42) ◽  
pp. 17424-17427 ◽  
Author(s):  
Zhengtao Deng ◽  
Anirban Samanta ◽  
Jeanette Nangreave ◽  
Hao Yan ◽  
Yan Liu
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Core Shell ◽  
Fluorescent Emission ◽  
Near Ir

scholarly journals EXPERIMENTAL STUDY OF 3D SELF-ASSEMBLED PHOTONIC CRYSTALS AND COLLOIDAL CORE-SHELL SEMICONDUCTOR QUANTUM DOTS

2017 ◽  
Vol 24 (1&2) ◽  
pp. 161-170
Author(s):  
Pham Thu Nga ◽  
Vu Duc Chinh ◽  
Nguyen Xuan Nghia ◽  
Nguyen Viet Huy ◽  
Dao Nguyen Thuan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Quantum Dots ◽  
Optical Properties ◽  
Photonic Crystal ◽  
Photonic Crystals ◽  
Self Assembly ◽  
Photonic Band Gap ◽  
Semiconductor Quantum Dots ◽  
Core Shell ◽  
Sphere Diameter

In this contribution we present an experimental study of 3D opal photonic crystals. The samples are opals constituted by colloidal silica spheres, realized with self-assembly technique. The sphere diameter is selected in order to obtain coupling of the photonic band gap with the emission from CdSe/ZnS colloidal quantum dots. The quantum dots infiltrated in the opals is expected to be enhanced or suppressed depending on the detection angle from the photonic crystal. The structural and optical characterization of the SiO2 opal photonic crystals are performed by field-emission scanning electron microscopy and reflectivity spectroscopy. Measurements performed on samples permits to put into evidence the influence of the different preparation methods on the optical properties. Study of self-activated luminescence of the pure opals is also presented. It is shown that the luminescence of the sample with QDs have original QD emission and not due to the photonic crystal structure. The optical properties of colloidal core-shell semiconductor quantum dots of CdSe/ZnS which are prepared in our lab will be mention.

Bioconjugates of Luminescent CdSe-ZnS Quantum Dots with Engineered Recombinant Proteins: Novel Self-Assembled Tools for Biosensing

2000 ◽  
Vol 642 ◽  
Author(s):  
Ellen R. Goldman ◽  
Hedi Mattoussi ◽  
Phan T. Tran ◽  
George P. Anderson ◽  
J. Matthew Mauro
Keyword(s):  
Quantum Dots ◽  
Recombinant Proteins ◽  
Self Assembly ◽  
Emission Spectra ◽  
Igg Antibody ◽  
Photo Degradation ◽  
Size Dependent ◽  
Near Ir ◽  
Wide Range

ABSTRACTColloidal semiconductor quantum dots (QDs) are luminescent nanoparticles with size- dependent emission spectra spanning a wide range of wavelengths in the visible and near IR. This property, as well as their higher resistance to photo-degradation compared to organic dye labels, makes QDs potentially suitable for certain biomolecule tagging and multiplexing applications. We describe an electrostatic self-assembly approach for conjugating highly luminescent colloidal CdSe-ZnS core-shell QDs with engineered two-domain recombinant proteins to form conjugates for sensing and imaging applications. The design, preparation, and characterization of high quantum yield IgG antibody-binding protein G bioconjugates using luminescence, electrophoretic gel shift, and affinity assays is reported.

Using Quantum Dots for Liquid-Phase Thermometry at Near-Infrared Wavelengths in Silicon Devices

2010 ◽  
Author(s):  
Myeongsub Kim ◽  
Minami Yoda
Keyword(s):  
Quantum Dots ◽  
Liquid Phase ◽  
Spatial Resolution ◽  
Near Infrared ◽  
Core Shell ◽  
Temperature Sensitive ◽  
Core Diameter ◽  
Silicon Devices ◽  
Near Ir ◽  
Visible Wavelengths

The need for new thermal management technologies to cool electronic components with their ever-increasing density and power requirements has renewed interest in techniques for measuring liquid-phase coolant temperatures, especially nonintrusive techniques with micron-scale spatial resolution. A variety of optical liquid-phase thermometry techniques exploit the changes in the emission characteristics of fluorescent, phosphorescent or luminescent tracers suspended in a liquid-phase coolant. Such techniques are nonintrusive and have micron-scale spatial resolution, but they also require optical access to both excite and image the emissions. Silicon (Si), the leading material for electronic devices, is opaque at visible wavelengths, but is partially transparent in the near-infrared (IR). To date, the only tracers that emit at near-IR wavelengths with reasonable quantum yield are IR quantum dots (IRQD), colloidal nanocrystals of semiconductor materials such as lead sulfide (PbS). Previous work has shown that the intensity of emissions at 1.55 μm from PbS IRQD suspended in toluene are temperature-sensitive, decreasing by as much as 15% as the temperature increased from 20 °C to 60 °C. The accuracy of temperature measurements using PbS IRQD was estimated to be about 5 °C, based on 95% confidence intervals, where the major limit on the accuracy of the technique was the poor photostability of this material [1]. Recently, a new method for creating a cadmium sulfide (CdS) overcoat layer on PbS “cores” has been developed [2]. The experimental results presented here on the temperature sensitivity of these PbS/CdS core-shell infrared quantum dots with an emission peak around 1.35 μm and a diameter of 5.7 nm (with a core diameter of 4 nm) suggest that these new core-shell structures are more temperature-sensitive than the PbS cores. These core-shell quantum dots, when suspended in toluene, were found to have a 0.5% decrease in emission power per °C increase in temperature at suspension temperatures ranging from 20 °C to 60 °C. The uncertainty in the liquid-phase temperatures derived from these emissions was estimated to be less than 0.3 °C based on the standard deviation. Furthermore, the PbS/CdS quantum dots were highly photostable, with a consistent response more than 100 days after suspension. These results imply that that these new IRQD can be used to measure liquid-phase coolant temperatures without disturbing the flow of coolant at an accuracy comparable to commercially available thermocouples in monolithic Si devices.

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>

Carbon Nanotubes, Quantum Dots and Dendrimers as Potential Nanodevices for Nanotechnology Drug Delivery Systems

2013 ◽  
Vol 6 (3) ◽  
pp. 2113-2124
Author(s):  
Prashant Malik ◽  
Neha Gulati ◽  
Raj Kaur Malik ◽  
Upendra Nagaich
Keyword(s):  
Carbon Nanotubes ◽  
Drug Delivery ◽  
Quantum Dots ◽  
Self Assembly ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Atomic Scale ◽  
Sustained Drug Delivery ◽  
Pharmaceutical Nanotechnology ◽  
Conventional Device

Nanotechnology deal with the particle size in nanometers. Nanotechnology is ranging from extensions of conventional device physics to completely new approaches based upon molecular self assembly, from developing new materials with dimensions on the nanoscale to direct control of matter on the atomic scale. In nanotechnology mainly three types of nanodevices are described: carbon nanotubes, quantum dots and dendrimers. It is a recent technique used as small size particles to treat many diseases like cancer, gene therapy and used as diagnostics. Nanotechnology used to formulate targeted, controlled and sustained drug delivery systems. Pharmaceutical nanotechnology embraces applications of nanoscience to pharmacy as nanomaterials and as devices like drug delivery, diagnostic, imaging and biosensor materials. Pharmaceutical nanotechnology has provided more fine tuned diagnosis and focused treatment of disease at a molecular level.    

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