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
Citations
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Semiconductor Nanocrystals as Fluorescent Biological Labels
TL;DR: Semiconductor nanocrystals prepared for use as fluorescent probes in biological staining and diagnostics have a narrow, tunable, symmetric emission spectrum and are photochemically stable.
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Quantum Dot Bioconjugates for Ultrasensitive Nonisotopic Detection
Warren C. W. Chan,Shuming Nie +1 more
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Chemistry and properties of nanocrystals of different shapes.
TL;DR: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties are equally important.
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Quantum dot bioconjugates for imaging, labelling and sensing
TL;DR: This review looks at current methods for preparing QD bioconjugates as well as presenting an overview of applications, and concludes that the potential of QDs in biology has just begun to be realized and new avenues will arise as the ability to manipulate these materials improves.
Journal ArticleDOI
Shape control of CdSe nanocrystals
Xiaogang Peng,Liberato Manna,Liberato Manna,Liberato Manna,Weidong Yang,Weidong Yang,Weidong Yang,Juanita N. Wickham,Juanita N. Wickham,Juanita N. Wickham,Erik C. Scher,Erik C. Scher,Erik C. Scher,Andreas Kadavanich,Andreas Kadavanich,Andreas Kadavanich,A. P. Alivisatos,A. P. Alivisatos,A. P. Alivisatos +18 more
TL;DR: Control of the growth kinetics of the II–VI semiconductor cadmium selenide can be used to vary the shapes of the resulting particles from a nearly spherical morphology to a rod-like one, with aspect ratios as large as ten to one.
References
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Journal ArticleDOI
Coupled Composite CdS−CdSe and Core−Shell Types of (CdS)CdSe and (CdSe)CdS Nanoparticles
TL;DR: In this paper, two emission bands were observed in the coupled and in the core−shell type mixed semiconductor nanoparticles, which were attributed to the 1se−1sh excitonic emission of CdS.
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A picosecond bleaching study of quantum‐confined cadmium sulfide microcrystallites in a polymer film
TL;DR: In this article, the authors show that the exciton-trapped carrier interaction is mainly responsible for the observed bleaching of the excitonic absorption, and the recovery time of the absorption bleaching is determined by the trapped carrier relaxation time, which is sensitive to fabrication methods and can be controlled by surface chemistry.
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Demonstration of a shell-core structure in layered CdSe-ZnSe small particles by X-ray photoelectron and Auger spectroscopies
Carolyn F. Hoener,Kristi Ann Allan,Allen J. Bard,Alan Campion,Marye Anne Fox,Thomas E. Mallouk,Stephen E. Webber,J. M. White +7 more
TL;DR: The potential positioning or different cations near the surface or at the center or small layered CdZnSe particles believed to have a shell-core structure has been demonstrated by the relative attenuation or the primary photoelectron and X-ray excited Auger signals from each cation as discussed by the authors.
Journal ArticleDOI
Quantum confinement in semiconductor heterostructure nanometer-size particles.
TL;DR: Nanometer-size semiconductor particles coated with another semiconductor can exhibit unusual and interesting phenomena associated with the redistribution of the electron and hole wave functions.
Journal ArticleDOI
Cathodoluminescence and photoluminescence of highly luminescent CdSe/ZnS quantum dot composites
Javier Rodríguez-Viejo,Klavs F. Jensen,Hedi Mattoussi,J. Michel,B. O. Dabbousi,Moungi G. Bawendi +5 more
TL;DR: In this article, the authors report room-temperature cathodoluminescence and photoluminecence spectra originating from ZnS overcoated CdSe nanocrystals, 33 and 42 A in diameter, embedded in a znS matrix.