Download or read book Synthesis of Quantum Dots with Tunable Fluorescence Lifetimes written by Thomas Michael Barnard and published by . This book was released on 2005 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dots are semiconductor crystals less than ̃10 nm in diameter. At this size, regime quantum confinement effects become significant. With cadmium selenide for example, a strong fluorescence becomes evident in the visible range once the spheres approach this scale. This fluorescence emission wavelength can be tuned from blue-green to red by merely changing the diameter of the sphere. The fluorescent properties of CdSe quantum dots have been exploited in numerous applications such as microscopic biological imaging, where the quantum dots perform better than traditional organic dyes. We have synthesized a new hybrid material that combines the remarkable fluorescent attributes of quantum dots with the long-excited state lifetimes of lanthanide complexes. In this new material, the lanthanide that is attached to the quantum dot can absorb light from a very short laser pulse (̃ 5 nanoseconds) and stay excited for a long period of time (microseconds to milliseconds). Eventually the excitation energy from the lanthanide is transferred to the quantum dot causing the quantum dot to fluoresce, effectively lengthening the lifetime of the quantum dot by several orders of magnitude. Furthermore, the lifetime is a function of the separation between the lanthanide and the quantum dot. By adjusting the separation between them, the fluorescent lifetimes of the quantum dots could be tuned. One potential application for this new tunable material would be for making nanoscale barcodes.
Download or read book Synthesis and Characterization of Fluorescence Lifetime Probe Library Constructed Using Quantum Dots and Organic Dyes in a Multicomponent Silica Shell written by Ashwin Melkote Kainkaryam and published by . This book was released on 2017 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the recent years, significant emphasis is dedicated towards the application of nanomaterials for targeted deliveries. Using the diverse optic properties of quantum dots and fluorescent dyes and the versatile advantages of silica shell such as being biocompatible, their ease of synthesis and their drug loading platforms, they are used in biomedical and biological applications. This project explains the synthesis and characterization of multiplexed nanoprobes which are used for cancer detection studies. The nanoprobes were synthesized with various sizes and aspect ratios, involving various fluorescent dyes with a wide range of lifetime., and with varied loading concentrations of dyes and quantum dots as cores to sandwiching dyes between a shell and a core.
Download or read book Synthesis and Structural Characterization of ZnTe ZnSe Core shell Tunable Quantum Dots written by Juan Guan and published by . This book was released on 2008 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Colloidal semiconductor nanocrystals or quantum dots have attracted much attention recently with their unique optical properties. Here we present a novel approach to synthesize ZnTe/ZnSe core/shell tunable quantum dots. Characterizations such as transmission electron microscopy, wavelength dispersive X-ray spectroscopy, powder x-ray diffraction are employed to give evidence for the core/shell structure. Absorption, and photoluminescence spectra demonstrate the tunability of this ZnTe/ZnSe core/shell system, and fluorescence lifetime decays suggest a core/shell structure is made.
Download or read book Silver Micro Nanoparticles written by Samir Kumar and published by BoD – Books on Demand. This book was released on 2021-09-15 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the different methodologies for producing and synthesizing silver nanoparticles (AgNPs) of various shapes and sizes. It also provides an in-depth understanding of the new methods for characterizing and modifying the properties of AgNPs as well as their properties and applications in various fields. This book is a useful resource for a wide range of readers, including scientists, engineers, doctoral and postdoctoral fellows, and scientific professionals working in specialized fields such as medicine, nanotechnology, spectroscopy, analytical chemistry diagnostics, and plasmonics.
Download or read book SYNTHESIS AND BIOLOGICAL APPLICATIONS OF HEAVY METAL FREE SEMICONDUCTOR NANOCRYSTALS written by Ying Qi and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor nanocrystals, also called quantum dots (QDs), are an interesting class of materials exhibiting size-tunable optical properties. QDs are attractive for a variety of applications, such as biological sensing and imaging, high color definition display technologies, and photovoltaics. The most widely studied QDs are compound semiconductors of the type CdX and PbX (with X= S, Se, and Te). The absorption and fluorescence emission wavelengths of these QDs span the visible and near infrared (NIR) regions of the electromagnetic spectrum. However, the highly toxic heavy metals Cd and Pb contained in these materials are problematic for their widespread use in commercial applications. Substitution of the heavy metals with Zn and Sn can yield QDs that are less toxic and more environmentally friendly. ZnSe QDs are highly luminescent in the UV-blue region of the spectrum and can be engineered to emit at longer wavelengths by doping them with transition metals, such as Mn or Cu. Encapsulation of ZnSe QDs with an inorganic shell, such as ZnS, has been shown to increase their stability and fluorescence intensity (quantum yield). However, the thermodynamic stability of such core/shell particles must be studied to understand the feasibility and long-term stability of atomically-abrupt interfaces between the core and the shell. The thermodynamic stability of ZnSe/ZnTe and ZnTe/ZnSe core/shell QDs was explored in this study. It was found that ZnSe/ZnTe core/shell QDs are thermodynamically more stable than ZnTe/ZnSe core/shell QDs. Functionalization of the surface of the QDs with biomolecules enables their use in biological sensing and imaging applications. A ZnSe-based QD-DNA biosensor was fabricated and characterized using a novel portable time-domain LED fluorimeter that enables nanosecond fluorescence lifetime measurements. SnSe QDs that absorb near-infrared (NIR) radiation are attractive nano-materials for applications in photovoltaics, photodetectors and photothermal therapy. A new synthesis method for small-size (
Download or read book Ternary Quantum Dots written by Oluwatobi Samuel Oluwafemi and published by Woodhead Publishing. This book was released on 2021-07-02 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ternary Quantum Dots: Synthesis, Properties, and Applications reviews the latest advances in ternary (I-III-VI) chalcopyrite quantum dots (QDs), along with their synthesis, properties and applications. Sections address the fundamental key concepts of ternary quantum dots, progress in synthesis strategies (i.e., organic and aqueous synthesis), and characterization methods (i.e., transmission electron microscopy, dynamic light scattering, etc.). Properties of ternary quantum dots are comprehensively reviewed, including optical, chemical and physical properties. The factors and mechanisms of the cytotoxicity of ternary quantum dot-based nanomaterials are also described. Since ternary chalcopyrite quantum dots are less toxic and more environmentally benign than conventional binary II-VI chalcogenide quantum dots, they are being investigated to replace conventional quantum dots in a range of applications. Thus, this book reviews QDs in various applications, such as solar cells, photocatalytic, sensors and bio-applications. Reviews fundamental concepts of ternary quantum dots and quantum dot-nanocomposites including the most relevant synthesis strategies, key properties, and characterization techniques Delves into the cytotoxicity of quantum dots looking at the factors and mechanisms that influence cytotoxicity including demonstration of cytotoxicity assays for in vitro and in vivo tests Touches on the many applications of ternary quantum dots including biomedical applications, applications in solar cells, sensing applications, and photocatalytic applications
Download or read book Nanocrystal Quantum Dots written by Victor I. Klimov and published by CRC Press. This book was released on 2017-12-19 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of recent advancements in colloidal nanocrystals and quantum-confined nanostructures, Nanocrystal Quantum Dots is the second edition of Semiconductor and Metal Nanocrystals: Synthesis and Electronic and Optical Properties, originally published in 2003. This new title reflects the book’s altered focus on semiconductor nanocrystals. Gathering contributions from leading researchers, this book contains new chapters on carrier multiplication (generation of multiexcitons by single photons), doping of semiconductor nanocrystals, and applications of nanocrystals in biology. Other updates include: New insights regarding the underlying mechanisms supporting colloidal nanocrystal growth A revised general overview of multiexciton phenomena, including spectral and dynamical signatures of multiexcitons in transient absorption and photoluminescence Analysis of nanocrystal-specific features of multiexciton recombination A review of the status of new field of carrier multiplication Expanded coverage of theory, covering the regime of high-charge densities New results on quantum dots of lead chalcogenides, with a focus studies of carrier multiplication and the latest results regarding Schottky junction solar cells Presents useful examples to illustrate applications of nanocrystals in biological labeling, imaging, and diagnostics The book also includes a review of recent progress made in biological applications of colloidal nanocrystals, as well as a comparative analysis of the advantages and limitations of techniques for preparing biocompatible quantum dots. The authors summarize the latest developments in the synthesis and understanding of magnetically doped semiconductor nanocrystals, and they present a detailed discussion of issues related to the synthesis, magneto-optics, and photoluminescence of doped colloidal nanocrystals as well. A valuable addition to the pantheon of literature in the field of nanoscience, this book presents pioneering research from experts whose work has led to the numerous advances of the past several years.
Download or read book Carbonaceous Quantum Dots Synthesis And Applications written by Kulvinder Singh and published by Bentham Science Publishers. This book was released on 2023-08-09 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference is a comprehensive guide to carbon quantum/ dots (CQDs) for researchers. The book includes ten chapters that explain the synthesis of CQDs, their chemical properties and their application in the field of nanotechnology. The content starts with a detailed introduction to CQDs, followed by the synthesis, chemical properties, and characterization of quantum dots. Subsequent chapters cover CQD application in the fabrication of biomedical materials, chemical sensing, wastewater treatment, toxicology, and energy storage. The final chapter of the book explores the future prospects of these quantum dots which gives a glimpse of new horizons in research and development. This book provides guidance to students and researchers who require an understanding of carbonaceous quantum dots. It also serves as a handbook for professionals, researchers and students working in chemical technology sectors.
Download or read book Colloidal Quantum Dot Optoelectronics and Photovoltaics written by Gerasimos Konstantatos and published by Cambridge University Press. This book was released on 2013-11-07 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: Captures the most up-to-date research in the field, written in an accessible style by the world's leading experts.
Download or read book Quantum Dots for DNA Biosensing written by Jun-Jie Zhu and published by Springer Science & Business Media. This book was released on 2013-12-04 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a broad introduction to all major aspects of quantum dot properties including fluorescence, electrochemical, photochemical and electroluminescence. Such properties have been produced for applications in biosensing, cell tracking, in vivo animal imaging and so on. It focuses on their special applications in DNA biosensing and provides readers with detailed information on the preparation and functionalization of quantum dots and the fabrication of DNA biosensors, using examples to show how these properties can be used in DNA biosensor design and the advantages of quantum dots in DNA biosensing. Further new emerging quantum dots such as metal nanoclusters and graphene dots and their applications in DNA biosensing have also been included.
Download or read book Encyclopedia of Color Science and Technology written by Renzo Shamey and published by Springer Nature. This book was released on 2023-09-29 with total page 1634 pages. Available in PDF, EPUB and Kindle. Book excerpt: This fully revised and expanded 2nd edition provides a single authoritative resource describing the concepts of color and the application of color science across research and industry. Significant changes for the 2nd edition include: New and expanded sections on color engineering More entries on fundamental concepts of color science and color terms Many additional entries on specific materials Further material on optical concepts and human visual perception Additional articles on organisations, tools and systems relevant to color A new set of entries on 3D presentation of color In addition, many of the existing entries have been revised and updated to ensure that the content of the encyclopedia is current and represents the state of the art. The work covers the full gamut of color: the fundamentals of color science; the physics and chemistry; color as it relates to optical phenomena and the human visual system; and colorants and materials. The measurement of color is described through entries on colorimetry, color spaces, color difference metrics, color appearance models, color order systems and cognitive color. The encyclopedia also has extensive coverage of applications throughout industry, including color imaging, color capture, display and printing, and descriptions of color encodings, color management, processing color and applications relating to color synthesis for computer graphics are included. The broad scope of the work is illustrated through entries on color in art conservation, color and architecture, color and education, color and culture, and biographies of some of the key figures involved in color research throughout history. With over 250 entries from color science researchers across academia and industry, this expanded 2nd edition of the Encyclopedia of Color Science and Technology remains the most important single resource in color science.
Download or read book Synthesis and Characterization of Infrared Quantum Dots written by Daniel Kelly Harris and published by . This book was released on 2014 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the development of synthetic methods to create application ready quantum dots (QDs) in the infrared for biological imaging and optoelectronic devices. I concentrated primarily on controlling the size and size distribution of indium arsenide and cadmium arsenide QDs. In the nanocrystal community, classical nucleation and growth is often invoked to explain size focusing. However, this model lacks predictive power and contradicts what is known about the chemistry of QD growth. I try to relate my experimental approach and my conclusions to our understanding of the mechanism of particle growth. This approach led me to explore the role of precursor conversion rate in the growth of III-V QDs and to develop a continuous injection synthesis method that I used to make both III-V and cadmium arsenide QDs. Cadmium arsenide (Cd 3As 2 ) is a narrow gap semiconductor that can form QDs with tunable emission between 530nm and 2000nm. I developed a synthetic strategy to precisely control the size of Cd3As 2 QDs while maintaining a narrow size distribution. Continuous precursor injection was used to drive growth and suppress size broadening. The quantum yields of Cd3As 2 QDs produced using this method ranged as high as 80%, and their emission is tunable over a broad range with narrow linewidths. However, they were found to be unstable in ambient conditions. Nevertheless, by processing in inert conditions we were able to make a crude photodetector that demonstrates that Cd3As 2 QDs are sufficiently stable for use in optoelectronic devices. Although growth of a Cd3 P2 shell provided enough added stability to observe emission after ligand exchange into water, these core-shell structures do not seem to be robust enough for biological applications. Indium arsenide (InAs) QDs are more easily stabilized with a core-shell structure. However, the spectral linewidths are broad and existing synthetic techniques produce only small particles with limited spectral tunability. Models predicted that decreasing precursor reactivity would produce larger, more monodisperse particles. Therefore, I chemically modified the group-V precursor to reduce reactivity. I made a library of group-V precursors, and I developed a framework for comparing the QDs that they produced and measuring the kinetics of precursor conversion and particle growth. Although we successfully reduced precursor reactivity, we found that the effect on particle size was minimal and that the least reactive precursors produced particles with inferior size distributions. To find another way to try to improve III-V synthesis, I adapted the continuous injection method developed for making Cd3As 2. Using this strategy, I was able to produce InAs QDs with broadly tunable size and narrow spectral features. However, continuous injection ceases to drive particle growth beyond about 5nm in diameter. We examined why particle growth stops, and proposed a strategy to prolong growth and size focusing. Ultimately, the continuous injection technique allowed us to produce InAs QDs with infrared emission and narrow spectral features that were ideally suited for producing QDs optimized for deep tissue imaging in mice. By adding a shell of CdSe, CdS, or ZnSe, the quantum yield and stability were enhanced. These emitters allowed us to see biodistribution and biological processes occurring inside live mice. Although we found that precursor chemistry did not affect particle growth to the degree we hoped, we were able to produce application ready QDs via a continuous injection procedure. Continuous injection synthesis of QDs is a precise way to tune QD size while maintaining narrow size distributions. We have used this technique to produce QDs with the specifications required for high impact applications.
Download or read book Nanoparticles written by Celso de Mello Donegá and published by Springer. This book was released on 2014-10-21 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book can be roughly divided into three parts: fundamental physico-chemical and physical principles of Nanoscience, chemistry and synthesis of nanoparticles, and techniques to study nanoparticles. The first chapter is concerned with the origin of the size dependence of the properties of nanomaterials, explaining it in terms of two fundamental nanoscale effects. This chapter also serves as a general introduction to the book, briefly addressing the definition and classification of nanomaterials and the techniques used to fabricate and study them. Chapter 2 lays out the theoretical framework within which to understand size effects on the properties of semiconductor nanocrystals, with particular emphasis on the quantum confinement effect. The optical properties of metal nanoparticles and metal nanostructures (periodic lattices) are discussed in Chapter 3. Chapter 4 is devoted to nanoporous materials, treating in detail their synthesis, structure and functional properties, as well as the physical properties of liquids confined in nanopores. The preparation methods, characterization techniques, and applications of supported nanoparticles are covered in Chapter 5. The sixth Chapter presents the essential physical-chemical concepts needed to understand the preparation of colloidal inorganic nanoparticles, and the remarkable degree of control that has been achieved over their composition, size, shape and surface. The last four Chapters are dedicated to a few selected characterization techniques that are very valuable tools to study nanoparticles. Chapter 7 concentrates on electron microscopy techniques, while Chapter 8 focuses on scanning probe microscopy and spectroscopy. Electron paramagnetic resonance (EPR) based spectroscopic techniques and their application to nanoparticles are explored in Chapter 9. Finally, Chapter 10 shows how solution Nuclear Magnetic Resonance (NMR) spectroscopic techniques can be used to unravel the surface chemistry of colloidal nanoparticles.
Download or read book Applications of Quantum Dots written by Abhishek Gupta and published by Arcler Press. This book was released on 2018-12 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applications of Quantum Dots starts with a basic introduction that includes the characterization, usage and preparation in biological systems. Quantum dots have a broad spectrum of applications and this text book has covered the major applications like uncovering active precursors in colloidal quantum dot synthesis or designing artificial 2D crystals with site and size controlled quantum dots. The readers can also get the information regarding the recent developments in quantum dots/cnt co-sensitized organic solar cells and accumulation and distribution of non-targeted and anti-cd44-conjugated quantum dots in distinct phenotypes of breast cancer. Further the book also highlights the potential use of quantum dots in flow cytometry.
Download or read book Quantum dot Based Light emitting Diodes written by Morteza Sasani Ghamsari and published by BoD – Books on Demand. This book was released on 2017-10-25 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dot-based light emitting diodes were assigned to bringing together the latest and most important progresses in light emitting diode (LED) technologies. In addition, they were dedicated to gain the perspective of LED technology for all of its advancements and innovations due to the employment of semiconductor nanocrystals. Highly selective, the primary aim was to provide a visual source for high-urgency work that will define the future directions relating to the organic light emitting diode (OLED), with the expectation for lasting scientific and technological impact. The editor hopes that the chapters verify the realization of the mentioned aims that have been considered for editing of this book. Due to the rapidly growing OLED technology, we wish this book to be useful for any progress that can be achieved in future.
Download or read book Perovskite Quantum Dots written by Ye Zhou and published by Springer Nature. This book was released on 2020-08-27 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses perovskite quantum dots, discussing their unique properties, synthesis, and applications in nanoscale optoelectronic and photonic devices, as well as the challenges and possible solutions in the context of device design and the prospects for commercial applications. It particularly focuses on the luminescent properties, which differ from those of the corresponding quantum dots materials, such as multicolor emission, fluorescence narrowing, and tunable and switchable emissions from doped nanostructures. The book first describes the characterization and fabrication of perovskite quantum dots. It also provides detailed methods for analyzing the electrical and optical properties, and demonstrates promising applications of perovskite quantum dots. Furthermore, it presents a series of optoelectronic and photonic devices based on functional perovskite quantum dots, and explains the incorporation of perovskite quantum dots in semiconductor devices and their effect of the performance. It also explores the challenges related to optoelectronic devices, as well as possible strategies to promote their commercialization. As such, this book is a valuable resource for graduate students and researchers in the field of solid-state materials and electronics wanting to gain a better understanding of the characteristics of quantum dots, and the fundamental optoelectronic properties and operation mechanisms of the latest perovskite quantum dot-based devices.
Download or read book Core Shell Quantum Dots written by Xin Tong and published by Springer Nature. This book was released on 2020-07-01 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book outlines various synthetic approaches, tuneable physical properties, and device applications of core/shell quantum dots (QDs). Core/shell QDs have exhibited enhanced quantum yield (QY), suppressed photobleaching/blinking, and significantly improved photochemical/physical stability as compared to conventional bare QDs. The core-shell structure also promotes the easy tuning of QDs’ band structure, leading to their employment as attractive building blocks in various optoelectronic devices. The main objective of this book is to create a platform for knowledge sharing and dissemination of the latest advances in novel areas of core/shell QDs and relevant devices, and to provide a comprehensive introduction and directions for further research in this growing area of nanomaterials research.
