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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TLDR
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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Sequential Cation Exchange in Nanocrystals: Preservation of Crystal Phase and Formation of Metastable Phases
Hongbo Li,Marco Zanella,Alessandro Genovese,Mauro Povia,Andrea Falqui,Cinzia Giannini,Liberato Manna +6 more
TL;DR: It is demonstrated that it is possible to convert CdSe nanocrystals of a given size, shape, and crystal structure into ZnSe Nanocrystals that preserve all these characteristics of the starting particles through a sequence of two cation exchange reactions.
Journal ArticleDOI
Sorting fluorescent nanocrystals with DNA.
Daniele Gerion,Wolfgang J. Parak,Shara C. Williams,Daniela Zanchet,Christine M. Micheel,A. Paul Alivisatos +5 more
TL;DR: The possibility of directing fluorescent nanocrystals toward specific biological targets and detecting them, combined with their superior photostability compared to organic dyes, opens the way to improved biolabeling experiments, such as gene mapping on a nanometer scale or multicolor microarray analysis.
Journal ArticleDOI
Freely Dispersible Au@TiO2, Au@ZrO2, Ag@TiO2, and Ag@ZrO2 Core−Shell Nanoparticles: One-Step Synthesis, Characterization, Spectroscopy, and Optical Limiting Properties
Renjis T. Tom,A. Sreekumaran Nair,Navinder Singh,M. Aslam,C. L. Nagendra,Reji Philip,K. Vijayamohanan,Thalappil Pradeep +7 more
TL;DR: In this paper, a one-step route for the synthesis of Au@TiO2 and Ag@ZrO2 particles with controllable shell thickness is described, with a crystalline core in the size range of 30−60 nm diameter and an amorphous shell of ∼3 nm thickness.
Journal ArticleDOI
Surface modification to reduce nonspecific binding of quantum dots in live cell assays.
Elizabeth L. Bentzen,Ian D. Tomlinson,John N. Mason,Paul J. Gresch,Michael R. Warnement,David W. Wright,Elaine Sanders-Bush,Randy D. Blakely,Sandra J. Rosenthal +8 more
TL;DR: Evidence suggests that nonspecific binding is related to cell type and may be significantly reduced by functionalizing quantum dots with poly(ethylene glycol) ligands (PEG).
Journal ArticleDOI
Current directions in core–shell nanoparticle design
TL;DR: This overview is mainly based on frequently cited and more specialized recent review articles from leaders in their respective field, and considers a variety of nanoscopic core-shell architectures from highly fluorescent nanoparticles (NPs), protected magnetic NPs, multifunctional NPS, thermoresponsive NPs and biocompatible systems to, finally, smart drug-delivery systems.
References
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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.