Download or read book Synthesis and Characterization of Cadmium Selenide CdSe Quantum Dots Using Inverse Micelle Technique written by Nor Aliya Hamizi and published by . This book was released on 2011 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Zinc Doped Cadmium Selenide Quantum Dots Via Inverse Micelle Technique written by Fatihah Aplop and published by . This book was released on 2015 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis of Cadmium Selenide Quantum Dots for Fabrication of Hybrid Light Emitting Diodes written by Michael Zachary McCreary and published by . This book was released on 2014 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: The synthesis of CdSe quantum dots was carried out using a variety of methods including co-precipitation method, reverse micellar method, and hot injection method. Of these three methods, only the hot injection method produced an immediately viable product for application in the hybrid light emitting diode proposed. The co-precipitation method did generate the ability to perform the reverse micellar method which produced ~30 nm diameter nanorods of mostly amorphous material. These rods were analyzed using XRD, and TEM. The hot injection method using octadecene as the solvent and various ligands, including oleic acid, benzene-1,4-dithiol, mercapto-benzoic acid and TOP, created quantum dots exhibiting photoluminescence in the green region of the visible spectrum. These quantum dots were characterized using UV-Visible Spectroscopy and Photoluminescence Spectroscopy. The oleic acid capped QD had a characteristic wavelength of 560 nm. While the mercapto-benzoic acid and benzene-1,4-dithiol capped QD had a characteristic wavelengths of 510 nm and 555 nm, respectively, all under the same operating conditions. For the purposes of device fabrication, the NN-Labs QDs were mostly used because their performance was much better than quantum dots synthesized in house. The fabrication of a hybrid light emitting diode has been developed with the structure ITO/PEDOT:PSS/PVK/CdSe QD/Alq3/Al. The device has exhibited a turn-on voltage from 2-3 V with currents ranging from 4-5 mA. The PEDOT:PSS layer was deposited using spin coating and analyzed using Photoluminescence Spectroscopy, Atomic Force Microscopy, Optical Microscopy, and Surface Profiling. The layer produce is sufficient for device fabrication. To facilitate proper hole transport and a sufficient quantum dot layer, a PVK/QD composite solution was used to create a monolayer layer of quantum dots by phase separation of the solutes in the solution. Alq3 and Al were deposited using thermal evaporation techniques.

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 GB T 24370 2009 Translated English of Chinese Standard GB T 24370 2009 GBT24370 2009 written by https://www.chinesestandard.net and published by https://www.chinesestandard.net. This book was released on 2024-09-26 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Standard specifies the UV-Vis absorption spectroscopy for the characterization of cadmium selenide (CdSe) quantum dot nanocrystals. This Standard is applicable to the dispersion liquid of cadmium selenide quantum dot nanocrystals coated with surfactant molecule---TOPO, Trioctylphosphine formed in n-hexane. The UV-Vis absorption spectrum characterization of dispersion liquids of cadmium selenide quantum dot nanocrystals coated with other surfactant molecules formed in various non-polar reagents, cadmium selenide quantum dot nanocrystals synthesized in aqueous systems and semiconductor quantum dot nanocrystals of other compositions may also take this Standard as a reference.

Download or read book Synthesis and Characterization Studies of Cadmium Selenide Quantum Dots written by Shiau Ying Ch'ng and published by . This book was released on 2010 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Synthesis and Characterization of Size Tuning Glutathione Capped Cadmium Selenide Quantum Dots written by Harshani Niroshika Rathnaweera and published by . This book was released on 2015 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization Studies of Cadmium Selenide Zinc CdSe Zn Quantom Dots written by Siti Rawasiah Sukardi and published by . This book was released on 2013 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Sulfide and Selenide Nanoparticles written by Geoffrey Douglas McCool and published by . This book was released on 2004 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanoscale Materials written by Luis M. Liz-Marzán and published by Springer Science & Business Media. This book was released on 2007-05-08 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organized nanoassemblies of inorganic nanoparticles and organic molecules are building blocks of nanodevices, whether they are designed to perform molecular level computing, sense the environment or improve the catalytic properties of a material. The key to creation of these hybrid nanostructures lies in understanding the chemistry at a fundamental level. This book serves as a reference book for researchers by providing fundamental understanding of many nanoscopic materials.

Download or read book Synthesis and Characterization of CdSe Quantum Dots for Solar Cell Application written by Sinovuyo Makinana and published by . This book was released on 2017 with total page 232 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 Patterning of Cadmium Selenide Quantum Dot Nanocrystals for Use with Photovoltaic Applications written by Joseph Edison Weaver and published by . This book was released on 2012 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, cadmium selenide (CdSe) quantum dots (QDs) are synthesized and characterized for patterning applications as well as for photovoltaic devices. The QDs were patterned and embedded into various polymers to form fluorescent composites. Their photophysical properties were investigated in detail. Through template assisted deposition the QDs-polymer composites were patterned into fluorescent nanorods. CdSe QDs were combined with multi-wall carbon nanotubes (CNTs) using a synthesized organic perylene derivative dye (N,N'-di(ethanethiol)-perylene-3,4,9,10-tetracarboxyl diimide) (ETPTCDI) as a link between QDs and CNTs. Upon testing, the QDs-ETPTCDI-CNTs nanocomposite displayed photoactive properties. Photophysical quenching studies of QD-ETPTCDI-CNTs provided better understanding of the electron-hole transfer of each component in the nanocomposite. The nanocomposite material was patterned onto microelectrode devices for photocurrent measurements under an AM1.5 solar simulated light source. These nanocomposites can be used as photovoltaic devices. The preliminary characterization studies of the device show excellent photoresponse under AM1.5 solar simulated light. The band gap alignment of each component of the nanocomposite and the charge transfer kinetics are the key to efficient electron-hole transfer. Optimization of the semiconducting material's interface can potentially make these nanocomposites a system for photovoltaic-based devices.

Download or read book Synthesis and Characterization of CdSe Quantum Dots by UV Vis Spectroscopy written by Petero Kwizera and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesis and Characterization of CdSe Quantum Dots by UV-Vis Spectroscopy.

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 Quantum DOT Synthesis Characterization and Analysis written by Andrew Kevin Tobias and published by . This book was released on 2012 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dot applications are numerous and range from photovoltaic devices and lasers, to bio labeling. Group II-VI semiconductor nanocrystals, specifically CdSe quantum dots, have been shown to be useful in applications such as, imaging, biological labeling, LEDs, lasers and solar cells. To further our understanding of these systems, we have synthesized a wide range of quantum dot samples, and characterized them using spectroscopic techniques. Difficulties in sample reproducibility and variance in the electronic band structure of quantum dots from sample to sample create the necessity for analysis techniques that can accurately and reproducibly provide band energies. Cyclic voltammetry (CV) has been used to estimate HOMO/LUMO levels in molecular species and, similarly, can also be used to estimate valence and conduction band levels in quantum dots. CV has the potential to become a useful tool in engineering new nanocrystal technology, by providing information necessary for predicting and modeling interfacial charge transfer to and from quantum dots. Despite the potential use of CV analysis, limitations arise due to the physical nature of nanocrystals. Solubility and diffusion come into play in solution-state experiments, while sample degradation is an issue in thin films. Carbon paste electrodes have been used in electrochemical studies to eliminate these issues. I will present data obtained using a carbon paste electrode to investigate energy levels in core CdSe and ligands bound to their surface. Importantly, the results of this work allow us to determine HOMO-LUMO energy differences for candidate nanocrystal-molecule electron transfer systems.

Download or read book Synthesis and Characterization of Doped Core shell Quantum Dots written by Elizabeth J. Sodt and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The central theme of the research performed is the systematic modification of the optical properties of quantum dots by the formation of a shell of another quantum dot of a different band gap energy. Core/shell quantum dots such as CdS:Mn/CdS. CdS:Mn/ZnS, and ZnS:Mn/CdS with various concentrations of dopant Mn2 in the core and shell concentrations have been synthesized under mild conditions in the aqueous phase using stoichiometric amounts of the surfactant stabilizer dodecyl sulfate. These quantum dots exhibit UV-vis, emission, and electron paramagnetic resonance (EPR) spectral behavior that is dependent on the concentration of the shell and the dopant Mn2 in the core. The emission intensities of the core quantum dots do exhibit a systematic variation with Mn2 concentration. When a shell is added a systematic variation in the emission intensity and lifetime that are inversely proportional to the concentration of the shell is observed. When the large band gap ZnS is added as a shell to the small band gap CdS, the Mn2+ ions migrate from the core to the shell which is manifested in the emission and EPR spectra. Additionally the mixing of the valence and conduction band energy states of the large and small band gap shell and core respectively is also manifested in the emission spectra. In the reverse case, namely when CdS is added as a shell to ZnS the migration is not observed and the mixing of the valence and conduction band energy levels is minimum. The tunable optical properties of these core/shell quantum dots make them excellent platforms for the generation of nanosensors for nerve gas analogs.