Download or read book Colloidal Synthesis and Optical Characterization of Monodisperse CdSe Semiconductor Quantum Dots written by Jason R. Seifter and published by . This book was released on 2006 with total page 77 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 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 Colloidal CdSe CdS Nanostructures written by Igor Coropceanu and published by . This book was released on 2016 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this thesis is the study of CdSe/CdS nanostructures, from their fundamental properties to their integration in practical devices. This material system has proven to be remarkably robust both as a platform for studying physics in confined semiconductors, as well as for enabling various optical and optoelectronic applications. In this thesis, we will discuss our recent efforts to improve the synthesis of CdSe/CdS structures, to better understand their optical properties and to use them to create highly performing luminescent solar concentrators. In the first part of the thesis we will discuss our efforts to improve the synthesis of CdSe/CdS nanostructures of different dimensionalities. In particular, we discuss the synthesis of CdSe/CdS quantum dots and seeded CdSe/CdS nanorods that have a near unity photoluminescence quantum yield and complete energy transfer from the shell to the core. Next, we discuss the fabrication of luminescent solar concentrators using these materials and the optical characterization of these devices. Finally, in the last section, we use a combination of synthesis, spectroscopy, and modeling to gain better insight into the photoluminescence lineshape of CdSe/CdS quantum dots.
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 584 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 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 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 Cadmium Telluride Quantum Dots written by John Donegan and published by CRC Press. This book was released on 2016-04-19 with total page 244 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 dev
Download or read book Synthesis and Structure of Colloidal Quantum Dots written by Ingrid Joylyn Paredes and published by American Chemical Society. This book was released on 2023-06-15 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology is an interdisciplinary field comprising materials scientists, chemists, physicists, and engineers dedicated to understanding the chemistry behind the associated synthesis, purification, modification, and applications. Already, nanotechnology has been instrumental to advances in medicine, electronics, catalysis, and cosmetics. The work of nanotechnologists has enabled society to move from the current “Silicon Age” into a new “Nano Age.” These alternatives to Si-based technologies are expected to combine the optoelectronic properties of bulk inorganic semiconductors with the benefits of additive device manufacturing—low cost, large area, and solution-based processes. This primer focuses on a class of nanomaterials known as colloidal quantum dots. Known for their solution processability and size-dependent optoelectronic properties, the study of colloidal quantum dots has garnered significant attention from the research community. The goal of this primer is to equip newcomers with the introductory knowledge and tools necessary to enter the field. As such, the scope of our work focuses on the synthesis and characterization of quantum dots; where possible, we point the reader to further reading specific to applications.
Download or read book Advanced Biomedical Engineering written by Gaetano Gargiulo and published by BoD – Books on Demand. This book was released on 2011-08-23 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a collection of recent and extended academic works in selected topics of biomedical signal processing, bio-imaging and biomedical ethics and legislation. This wide range of topics provide a valuable update to researchers in the multidisciplinary area of biomedical engineering and an interesting introduction for engineers new to the area. The techniques covered include modelling, experimentation and discussion with the application areas ranging from acoustics to oncology, health education and cardiovascular disease.
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 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 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capturing the most up-to-date research in colloidal quantum dot (CQD) devices, this book is written in an accessible style by the world's leading experts. The application of CQDs in solar cells, photodetectors and light-emitting diodes (LEDs) has developed rapidly over recent years, promising to transform the future of clean energy, communications, and displays. This complete guide to the field provides researchers, students and practitioners alike with everything they need to understand these developments and begin contributing to future applications. Introductory chapters summarise the fundamental physics and chemistry, whilst later chapters review the developments that have propelled the field forwards, systematically working through key device advances. The science of CQD films is explained through the latest physical models of semiconductor transport, trapping and recombination, whilst the engineering of organic and inorganic multilayered materials is shown to have enabled major advances in the brightness and efficiency of CQD LEDs.
Download or read book Semiconductor Nanocrystals written by Alexander L. Efros and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: A physics book that covers the optical properties of quantum-confined semiconductor nanostructures from both the theoretical and experimental points of view together with technological applications. Topics to be reviewed include quantum confinement effects in semiconductors, optical adsorption and emission properties of group IV, III-V, II-VI semiconductors, deep-etched and self assembled quantum dots, nanoclusters, and laser applications in optoelectronics.
Download or read book Colloidal Synthesis and Photophysical Characterization of Group IV Alloy and Group IV V Semiconductors written by Venkatesham Tallapally and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomaterials, typically less than 100 nm size in any direction have gained noteworthy interest from scientific community owing to their significantly different and often improved physical properties compared to their bulk counterparts. Semiconductor nanoparticles (NPs) are of great interest to study their tunable optical properties, primarily as a function of size and shape. Accordingly, there has been a lot of attention paid to synthesize discrete semiconducting nanoparticles, of where Group III-V and II-VI materials have been studied extensively. In contrast, Group IV and Group IV-V based nanocrystals as earth abundant and less-non-toxic semiconductors have not been studied thoroughly. From the class of Group IV, Ge1-xSnxalloys are prime candidates for the fabrication of Si-compatible applications in the field of electronic and photonic devices, transistors, and charge storage devices. In addition, Ge1-xSnx alloys are potentials candidates for bio-sensing applications as alternative to toxic materials. Tin phosphides, a class of Group IV-V materials with their promising applications in thermoelectric, photocatalytic, and charge storage devices. However, both aforementioned semiconductors have not been studied thoroughly for their full potential in visible (Vis) to near infrared (NIR) optoelectronic applications. In this dissertation research, we have successfully developed unique synthetic strategies to produce Ge1-xSnxalloy quantum dots (QDs) and tin phosphide (Sn3P4, SnP, and Sn4P3) nanoparticles with tunable physical properties and crystal structures for potential applications in IR technologies. Low-cost, less-non-toxic, and abundantly-produced Ge1-xSnxalloys are an interesting class of narrow energy-gap semiconductors that received noteworthy interest in optical technologies. Admixing of Îł-Sn into Ge results in an indirect-to-direct bandgap crossover significantly improving light absorption and emission relative to indirect-gap Ge. However, the narrow energy-gaps reported for bulk Ge1-xSnxalloys have become a major impediment for their widespread application in optoelectronics. Herein, we report the first colloidal synthesis of Ge1-xSnxalloy quantum dots (QDs) with narrow size dispersity (3.3±0.5 -- 5.9±0.8 nm), wide range of Sn compositions (0--20.6%), and composition-tunable energy-gaps and near infrared (IR) photoluminescence (PL). The structural analysis of alloy QDs indicates linear expansion of cubic Ge lattice with increasing Sn, suggesting the formation of strain-free nanoalloys. The successful incorporation of Îł-Sn into crystalline Ge has been confirmed by electron microscopy, which suggests the homogeneous solid solution behavior of QDs. The quantum confinement effects have resulted in energy gaps that are significantly blue-shifted from bulk Ge for Ge1-xSnxalloy QDs with composition-tunable absorption onsets (1.72±0.84 eV for x=1.5--20.6%) and PL peaks (1.62--1.31 eV for x=1.5--5.6%). Time-resolved PL (TRPL) spectroscopy revealed microsecond and nanosecond timescale decays at 15 K and 295 K, respectively owing to radiative recombination of dark and bright excitons as well as the interplay of surface traps and core electronic states. Realization of low-to-non-toxic and silicon-compatible Ge1-xSnxQDs with composition-tunable near IR PL allows the unprecedented expansion of direct-gap Group IV semiconductors to a wide range of biomedical and advanced technological studies. Tin phosphides are a class of materials that received noteworthy interest in photocatalysis, charge storage and thermoelectric devices. Dual stable oxidation states of tin (Sn2+ and Sn4+) enable tin phosphides to exhibit different stoichiometries and crystal phases. However, the synthesis of such nanostructures with control over morphology and crystal structure has proven a challenging task. Herein, we report the first colloidal synthesis of size, shape, and phase controlled, narrowly disperse rhombohedral Sn4P3, hexagonal SnP, and amorphous tin phosphide nanoparticles (NPs) displaying tunable morphologies and size dependent physical properties. The control over NP morphology and crystal phase was achieved by tuning the nucleation/growth temperature, molar ratio of Sn/P, and incorporation of additional coordinating solvents (alkylphosphines). The absorption spectra of smaller NPs exhibit size-dependent blue shifts in energy gaps (0.88--1.38 eV) compared to the theoretical value of bulk Sn3P4 (0.83 eV), consistent with quantum confinement effects. The amorphous NPs adopt rhombohedral Sn4P3 and hexagonal SnP crystal structures at 180 and 250 ̊C, respectively. Structural and surface analysis indicates consistent bond energies for phosphorus across different crystal phases, whereas the rhombohedral Sn4P3 NPs demonstrate Sn oxidation states distinctive from those of the hexagonal and amorphous NPs owing to complex chemical structure. All phases exhibit N(1s) and ʋ(N-H) energies suggestive of alkylamine surface functionalization and are devoid of tetragonal Sn impurities.
Download or read book Chemical Synthesis and Optical Characterization of Regular and Magic Sized CdS Quantum Dot Nanocrystals Using 1 Dodecanethiol written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, cadmium sulfide (CdS) quantum dot (QD) nanoparticles have been synthesized using a one-pot noninjection reaction procedure in solvent medium 1-octadecene. This approach used a cadmium salt and 1-dodecanethiol, an organic sulfur, as the cadmium and sulfur sources, respectively, along with a long-chain organic acid (myristic acid, lauric acid, or stearic acid). The acid has dual effects as a surface capping ligand and a solubility controlling agent as well. UV-Vis and photoluminescence (PL) spectrometry techniques were used to characterize the optical properties, along with transmission electron microscopy (TEM) to identify the structure and size. Our newly developed synthesis procedure allowed for investigation of both regular and "magic-sized" CdS QDs by systematically controlling reaction parameters such as reactant type, reactant concentration, and reaction temperature. The organic sulfur (1-dodecanethiol) proved to be a useful sulfur source for synthesizing magic-sized CdS QDs, previously unreported. Several distinctive size regimes of magic-sized quantum dots (MSQDs), including Families 378 and 407, were successfully produced by controlling a small number of factors. Finally, the understanding of controlled Cd release in a MSQD formation mechanism is developed.
Download or read book Synthesis and Surface Characterization of Semiconductor Nanocrystals for Photovoltaic Application written by Irina Lokteva and published by . This book was released on 2010 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the first part of the thesis, the kinetics of a novel colloidal synthesis of nearly monodisperse CdSe and CdS QDs involving in situ formed Cd particles was studied. Reactions with different types of Se and S precursors, Cd to Se and S ratio, and different amount of the stabilizer (oleic acid) were characterized by UV-Vis absorption spectroscopy. Transmission electron microscopy (TEM) was used to determine the size distribution of as-synthesized CdSe and CdS NCs. In the second part, a surface modification of originally oleic acid-capped CdSe QDs with pyridine molecules was carried out. The pyridine-treated NCs were characterized by different analytical methods. Then the pyridine-treated CdSe QDs were used for the fabrication of hybrid P3HT/CdSe solar cells. Additionally, a cross-linking procedure of the pyridine-treated NCs was applied to enable more efficient charge transfer between nanoparticles in the hybrid blends. engl.
Download or read book Synthesis and Optical Properties of Plasmonic Fluorescent Quantum Dots written by Botao Ji and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the surface plasmons in metallic nanostructures and the exceptional optical and electrical properties of colloidal semiconductor quantum dots (QDs), QD/metal hybrid nanostructures attract much attention. However, although these structures are very promising, colloidal single QD/gold hybrids have rarely been synthesized.We managed to develop for the first time a generalized synthetic route to synthesize a QD/SiO2/Au core/shell/shell hybrid structure (golden QDs). First, hydrophobic QDs are individually encapsulated in silica beads via reverse microemulsion. The obtained QD/SiO2 nanoparticles are then coated with a continuous gold nanoshell using a solution deposition process. The thicknesses of the silica and the gold layers can be tailored independently to various dimensions. We showed that single golden thick-shell CdSe/CdS QDs provide a system with a stable and poissonian emission at room temperature and a high photostability. This novel hybrid golden QD structure behaves as a plasmonic resonator with a strong (~ 6) Purcell factor, in very good agreement with simulations. We also present the self-assembly of hydrophobic QDs into colloidal superparticles (SPs). With a fine choice of QDs, SPs could indeed possess outstanding properties including non-blinking fluorescence, high fluorescence intensity and multi-color emission. Multi-functional SPs could also be obtained by mixing fluorescent or magnetic nanocrystals. The subsequent growth of a silica shell on the SPs allowed an enhancement of their stability and we demonstrated this silica shell could itself be covered by a gold nanoshell to further improve the SPs photostability and biocompatibility.
