Journal ArticleDOI
(CdSe)ZnS Core-Shell Quantum Dots - Synthesis and Characterization of a Size Series of Highly Luminescent Nanocrystallites
B. O. Dabbousi,Javier Rodríguez-Viejo,F. V. Mikulec,Jason Heine,Hedi Mattoussi,R. Ober,K. F. Jensen,‡,§ and,Moungi G. Bawendi +7 more
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In this paper, a synthesis of highly luminescent (CdSe)ZnS composite quantum dots with CdSe cores ranging in diameter from 23 to 55 A was reported.Abstract:
We report a synthesis of highly luminescent (CdSe)ZnS composite quantum dots with CdSe cores ranging in diameter from 23 to 55 A. The narrow photoluminescence (fwhm ≤ 40 nm) from these composite dots spans most of the visible spectrum from blue through red with quantum yields of 30−50% at room temperature. We characterize these materials using a range of optical and structural techniques. Optical absorption and photoluminescence spectroscopies probe the effect of ZnS passivation on the electronic structure of the dots. We use a combination of wavelength dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, small and wide angle X-ray scattering, and transmission electron microscopy to analyze the composite dots and determine their chemical composition, average size, size distribution, shape, and internal structure. Using a simple effective mass theory, we model the energy shift for the first excited state for (CdSe)ZnS and (CdSe)CdS dots with varying shell thickness. Finally, we characterize the...read more
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Photonic crystals from core-shell colloids with incorporated highly fluorescent quantum dots
TL;DR: In this paper, the preparation of nanoscaled PS/PMMA core-shell spheres with highly fluorescent CdS/ZnS coated CdSe quantum dots (QDs) integrated in the core was reported.
Journal ArticleDOI
High levels of atmospheric carbon dioxide necessary for the termination of global glaciation
TL;DR: In simulations with a general circulation model, the system remains far short of deglaciation even at atmospheric carbon dioxide concentrations of 550 times the present levels (0.2 bar of CO2), and it is found that at much higher carbon dioxide levels, degLaciation is unlikely unless unknown feedback cycles that are not captured in the model come into effect.
Journal ArticleDOI
From Artificial Atoms to Nanocrystal Molecules: Preparation and Properties of More Complex Nanostructures
TL;DR: In this paper, the nature of the coupling between nanocrystal atoms and its response to vibrations and deformations of the nanocrystals molecule bonds are discussed. And the authors discuss synthetic approaches, predicted and observed physical properties, and prospects and challenges toward this new class of materials.
Journal ArticleDOI
Highly Efficient Copper–Indium–Selenide Quantum Dot Solar Cells: Suppression of Carrier Recombination by Controlled ZnS Overlayers
Jae-Yup Kim,Jiwoong Yang,Jung Ho Yu,Woonhyuk Baek,Chul Ho Lee,Hae Jung Son,Taeghwan Hyeon,Min Jae Ko,Min Jae Ko +8 more
TL;DR: Impedance studies reveal that the thick ZnS overlayers do not affect the energetic characteristics of the photoanode, yet enhance the kinetic characteristics, leading to more efficient photovoltaic performance.
Journal ArticleDOI
Elementary Building Blocks of Self-Assembled Peptide Nanotubes
TL;DR: An exceptional quantum-confined approach is shown here for the self-assembly mechanism in bio-inspired materials, finding the elementary building block of the studied PNT, which is self-assembled from short peptides composed of two phenylalanine residues, to be 0D-quantum-confinement, also called a quantum dot (QD).
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Synthesis and characterization of nearly monodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallites
TL;DR: In this paper, a simple route to the production of high-quality CdE (E=S, Se, Te) semiconductor nanocrystallites is presented, based on pyrolysis of organometallic reagents by injection into a hot coordinating solvent.