Download or read book Synthesis Properties and Surface Modifications of Cdse Quantum Dots written by Himani Sharma and published by LAP Lambert Academic Publishing. This book was released on 2010-11 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emergence of colloidal semiconductor nanocrystals has generated great fundamental and technical interest in recent years. The size dependent emission property for Cadmium Selenide quantum dots renders it indispensable in the field of nanocrystal-based emitters used in electronic and bioelectronic devices. Investigation of these semiconductor quantum dots reveals the evolution of the electronic structure from an extended solid state to the molecular limit, an extremely important issue of basic and applied research in condensed matter physics. The work presented in this book mainly deals with the synthesis and characterization of chemically synthesized CdSe nanoparticles. A detailed investigation of the optical, structural and morphological properties of CdSe QDs and their correlation with both core and surface has been carried out. The theoretical aspect of quantum confinement and stability of CdSe quantum dots with organic and inorganic layers, are correlated to understand the surface modification aspects. Finally CdSe-polymer nanocomposites were discussed for their potential application in biomarkers and photo-electronic devices.
Download or read book Synthesis and Surface Modification of CdSe and CdS Quantum Dots Exhibiting High Quantum Yield written by Jeweliet A. Yost and published by . This book was released on 2011 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigates the effect of surface treatment with various reducing and oxidizing agents on the quantum yield (QY) of CdSe and CdS quantum dots (QDs).
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.
Download or read book Nanocrystals written by Sudheer Neralla and published by BoD – Books on Demand. This book was released on 2012-08-29 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystals research has been an area of significant interest lately, due to the wide variety of potential applications in semiconductor, optical and biomedical fields. This book consists of a collection of research work on nanocrystals processing and characterization of their structural, optical, electronic, magnetic and mechanical properties. Various methods for nanocrystals synthesis are discussed in the book. Size-dependent properties such as quantum confinement, superparamagnetism have been observed in semiconductor and magnetic nanoparticles. Nanocrystals incorporated into different material systems have proven to possess improved properties. A review of the exciting outcomes nanoparticles study has provided indicates further accomplishments in the near future.
Download or read book Quantum Dots written by Inamuddin and published by Materials Research Forum LLC. This book was released on 2021-04-05 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides a thorough survey of current research in quantum dots synthesis, properties, and applications. The unique properties of these new nanomaterials offer multifunctional applications in such fields as photovoltaics, light-emitting diodes, field-effect transistors, lasers, photodetectors, solar cells, biomedical diagnostics and quantum computing. Keywords: Quantum Dots (QD), Photovoltaics, Light-emitting Diodes, Field-effect Transistors, Lasers, Photodetectors, Solar Cells, Biomedical Diagnostics, Quantum Computing, QD Synthesis, Carbon QDs, Graphene QDs, QD Sensors, Supercapacitors, Magnetic Quantum Dots, Cellular/Molecular Separation, Chromatographic Separation Column, Photostability, Luminescence of Carbon QDs, QD Materials for Water Treatment, Semiconductor Quantum Dots, QD Drug Delivery, Antibacterial Quantum Dots.
Download or read book Synthesis and Characterizations of Pb modified CdSe Aqueous Quantum Dots and Their Applications in Quantum Dot Sensitized Solar Cells written by Cheng-Hsin Lu and published by . This book was released on 2016 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum Dots (QDs) are semiconductor nanocrystals with typical size ranges around 1-20 nm. They exhibit distinctive size-dependent photoluminescence (PL) properties due to the quantum confinement effect. QDs have great potentials in display, lighting, lasing, bioimaging, fluorescent label, sensor, photodetector, and photovoltaic applications, and have been widely studied in the past decades. Cadmium selenide (CdSe) QDs have been synthesized using an environmentally friendly, aqueous method under low temperature. While traditional QDs synthesized by hot injection method using organic solvent generally exhibit edge-state emission with narrow peaks, aqueous quantum dots (AQDs) tend to have trap-state emissions with broad peaks. The objective of this thesis is to investigate how Pb modifications in CdSe AQDs synthesis can affect the optoelectronic properties of the QDs and how these modifications affect their corresponding photovoltaic performance in quantum dot-sensitized solar cell (QDSSC) applications. Lead (Pb) precursor has been introduced either during the synthesis or after the synthesis of CdSe AQDs forming either Pb-doped or Pb-coated CdSe QDs, respectively. Pb-doped CdSe QDs exhibit red-shift in both absorption and emission spectra while Pb-coated CdSe QDs exhibit blue-shift in both absorption and emission spectra along with the generation of more surface defects. Although blue-shifted absorption indicating a narrower absorption range and the surface defects providing undesired recombination pathways are detrimental to solar cell performance, however surprisingly, we found that QDSSCs made from Pb-coated CdSe QDs actually had better solar cell performance than that made from Pb-doped CdSe QDs. We attributed this finding to a protection/passivation layer formed in-situ when the coated Pb react with the iodide/triiodide electrolyte during solar cell operation resulting in QDSSCs with better charge injection and stability.
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 written by Rakshit Ameta and published by Elsevier. This book was released on 2022-09-20 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum Dots: Fundamentals, Synthesis and Applications compiles key information, along with practical guidance on quantum dot synthesis and applications. Beginning with an introduction, Part One highlights such foundational knowledge as growth mechanisms, shape and composition, electrochemical properties, and production scale-up for quantum dots. Part Two goes on to provide practical guides to key chemical, physical and biological methods for the synthesis of quantum dots, with Part Three reviewing the application of quantum dots and a range of important use cases, including photocatalysis, energy cells and medical imaging. Drawing on the knowledge of its expert authors, this comprehensive book provides practical guidance for all those who already study, develop or use quantum dots in their work. - Presents the foundational information needed to effectively understand and manipulate quantum dot properties - Consolidates key methods of quantum dot synthesis in a single volume - Reviews both current and future practical applications of quantum dots across a range of important fields
Download or read book Efficient Computation of Quantum Dot Properties written by Nathan John Weeks and published by . This book was released on 2019 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconducting quantum dots (QDs) exhibit tunable size dependent properties, leading some to designate these materials as “artificial atoms”. Synthetic methods of CdSe QDs have been highly refined and typically involve one-pot seeding and growth, resulting in the generation of colloidal crystallites ranging in diameter from ~1nm to ~6nm and with size distributions as low as 10%. Several reports describe the observation of “magic size” QDs during the early stages of growth, characterized by a stepwise increase in QD size—as opposed to the typically-observed continuous growth of QD sizes. While postulated to result from QD structures of energetic stability, evidence of the nature of stable structures is limited in experiment by microscopy and in computational simulation by the sheer number of electrons present within even the smallest of QDs. This work highlights a new computational approach toward treatment of QD behavior that forgoes quantum mechanical (electronic state) information in lieu of computational speeds many orders of magnitude faster than ab initio methods. The modification of traditional charge equilibration (qEQ) methods to also account for the unique dielectric environment experienced by a QD during its synthesis (QD-qEQ) yields an approach that is fast and atomistic, providing rich information about the partial charge of each atom in the system at energetic equilibrium. When applied to a structure-set of 35,000+ unique wurtzite CdSe QDs with diameters ≤ 2.50 nm, energetic depressions are apparent at certain QD sizes, which agree generally with the sizes at which CdSe magic size QDs have been reported experimentally. Further, analysis of QD surface characteristics associated with such magic sizes yield surfaces made up of highly coordinated and relatively low energy atoms, suggesting that the magic size phenomenon is due to a thermodynamic stability afforded by certain QD surface atom arrangements. The accuracy and versatility of QD-qEQ positions this method as a potential candidate for simulation of QD properties at much larger scales, an intractable problem with traditional computational methods.
Download or read book Cadmium Telluride Quantum Dots written by John Donegan and published by CRC Press. This book was released on 2013-12-03 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last two decades, semiconductor quantum dots—small colloidal nanoparticles—have garnered a great deal of scientific interest because of their unique properties. Among nanomaterials, CdTe holds special technological importance as the only known II–VI material that can form conventional p–n junctions. This makes CdTe very important for the development of novel optoelectronic devices such as light-emitting diodes, solar cells, and lasers. Moreover, the demand for water-compatible light emitters and the most common biological buffers give CdTe quantum dots fields a veritable edge in biolabeling and bioimaging. Cadmium Telluride Quantum Dots: Advances and Applications focuses on CdTe quantum dots and addresses their synthesis, assembly, optical properties, and applications in biology and medicine. It makes for a very informative reading for anyone involved in nanotechnology and will also benefit those scientists who are looking for a comprehensive account on the current state of quantum dot–related research.
Download or read book Biosynthesis of Cadmium Chalcogenide Quantum Dots and Enhancement of Their Functional Properties Via Surface Modification written by Zhou Yang and published by . This book was released on 2016 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Post-treatments, such as core/shell growth, phase transfer, and photoenhancement were utilized to modify the surface chemistry of these nanocrystals to improve their properties for potential applications. Core/shell structures on both CdS and CdSe cores with different shell structure (ZnS for CdS, CdS for CdSe) were achieved. This significantly improved their optical properties, for example, core/shell CdSe/CdS exhibits a quantum yield up to 12 %. A facile phase transfer protocol was proposed to efficiently transfer the QDs from aqueous phase to organic phase. In addition, photoenhancement via UV illumination was also introduced for CdSe QDs and their photoluminescence was highly improved. Owing to the post-treatments, the qualities of these cell-based QDs are comparable to that from chemical synthesis routes. Our biosynthetic approach to cadmium chalcogenide QDs production provides a viable pathway to realize the promise of green biomanufacturing of these materials for optoelectronic, energy, medicine and other emerging technological applications.
Download or read book Colloidal Semiconductor Nanocrystals Synthesis Properties and Applications written by Vladimir Lesnyak and published by Frontiers Media SA. This book was released on 2020-01-06 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Photophysical Properties of CdSe Quantum Dots written by Nick Rightmire and published by . This book was released on 2010 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Semiconductor Nanocrystal Quantum Dots written by Andrey Rogach and published by Springer Science & Business Media. This book was released on 2008-09-02 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to specifically focus on semiconductor nanocrystals, and address their synthesis and assembly, optical properties and spectroscopy, and potential areas of nanocrystal-based devices. The enormous potential of nanoscience to impact on industrial output is now clear. Over the next two decades, much of the science will transfer into new products and processes. One emerging area where this challenge will be very successfully met is the field of semiconductor nanocrystals. Also known as colloidal quantum dots, their unique properties have attracted much attention in the last twenty years.
Download or read book Tuning the Optical Properties of Nanoscale Materials on Surfaces Through Controlled Exchange Reactions on Cadmium Selenide Quantum Dots and Patterning of Gold and QD Nanoparticle Arrays written by Arika Pravitasari and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work focused on the integration of CdSe quantum dots (QDs) and Au nanoparticles (NPs) as building blocks for the development of quantum dot and plasmonic based optical and sensing devices. The manipulation of nanomaterials was performed to tune their surface and optical properties to study their fundamental chemical and physical processes as well as their applications. First, the cation exchange reactions between CdSe QDs and Ag+ cations were explored as the surface properties of the QDs were altered. The surface properties of CdSe QDs were tuned by local exposure of laser through photopatterning. The CdSe QDs with different surface properties altered by photopatterning were then exposed to a solution of increasing Ag+ concentrations. The decrease in the photoluminescence intensity of CdSe QDs were monitored and used as an indication for the cation exchange reactions taking place. Photoluminescence data confirmed that the cation exchange reactions exhibited different efficiencies for QDs that were photo-altered in comparison to pristine QDs. The second area of the study employed the use of directed assembly to fabricate pattern arrays of Au NPs. Fabrication of metallic nanostructure arrays using polystyrene (PS) microspheres often required the use of photo-resist, chemical etching and metal evaporation processes, here they were use to direct the assembly of colloidal Au nanoparticles (NPs) by simple evaporative processes. This created an inexpensive and simple bench-top method for bottom-up fabrication of metallic nanostructure arrays. Optimum parameter for the formation of uniform Au nanoring arrays was achieved by controlling the relative humidity (RH) and the relative concentration of Au NPs to PS microspheres. The fabricated Au nanostructure arrays serve as great platforms not only for future applications in plasmonic based sensing and optical devices but also for the fundamental studies of their localized surface plasmon resonance (LSPR). An alternative method of patterning, a combination between the use of a self-assembled monolayer (SAM) molecular linker and PS mask fabricated via polydimethylsiloxane (PDMS) micro-stamp was also discussed briefly. Particle lithography is a versatile method and can be used to fabricate pattern array of different nanomaterials with similar surface affinities. It was then modified to reduce the non-specific binding of CdSe QDs forming uniform nanoring arrays. The photoluminescence of the fabricated CdSe nanoring arrays was then altered to locally tune their surface and optical properties. This allowed for the post-fabrication surface modification of each nanoring for the creation of CdSe nanoring arrays of different surface and optical properties. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151756
Download or read book Molecular Nano Dynamics written by Hiroshi Fukumura and published by John Wiley & Sons. This book was released on 2009-09-09 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt: From artificial surfaces to living cells, Molecular Nano Dynamics, Vol. I and Vol. II explores more than 40 important methods for dynamic observation of the nanoscale. Edited by absolute science greats from Japan, this two-volume set covers all important aspects of this topic: nanoscale spectroscopy and characterization tools, nanostructure dynamics, single living cell dynamics, active surfaces, and single crystals. Destined to be the definitive reference work on nanoscale molecular dynamics and their observation for years to come, this is a must-have reference for chemists, physicists, physical chemists, theoretical chemists, and materials scientists.
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.
