Journal ArticleDOI
Synthesis and Characterization of Surface-Modified Colloidal CdTe Quantum Dots
TLDR
In this paper, a controlled synthesis of quantized colloidal CdTe nanocrystals (in aqueous solutions) with narrow size distributions and stabilized against rapid oxidation was achieved by capping the quantum dot particles with 3-mercapto-1,2-propanediol.Abstract:
The controlled synthesis of quantized colloidal CdTe nanocrystals (in aqueous solutions) with narrow size distributions and stabilized against rapid oxidation was achieved by capping the quantum dot particles with 3-mercapto-1,2-propanediol. Nanocrystals (i.e., quantum dots) with mean diameters of 20, 25, 35, and 40 A were produced. Optical absorption spectra showed strong excitonic peaks at the smallest size; the absorption coefficient was shown to follow an inverse cube dependence on particle diameter, while the extinction coefficient per particle remained constant. The quantum yield for photoluminescence increased with decreasing particle size and reached 20% at 20 A. The valence band edges of the CdTe quantum dots were determined by pulse radiolysis experiments (hole injection from oxidizing radicals); the bandgaps were estimated from pulse radiolysis data (redox potentials of hole and electron injecting radicals) and from the optical spectra. The dependence of the CdTe bandgap on quantum dot size was found to be much weaker than predicted by the effective mass approximation; this result is consistent with recently published theoretical calculations by several groups. 36 refs., 5 figs., 1 tab.read more
Citations
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Journal ArticleDOI
Experimental Determination of the Extinction Coefficient of CdTe, CdSe, and CdS Nanocrystals
TL;DR: In this article, the extinction coefficient per mole of nanocrystals at the first exitonic absorption peak, e.g., for high-quality CdTe, CdSe, and CdS, was found to be strongly dependent on the size of the nanocrystal, between a square and a cubic dependence.
Journal ArticleDOI
Size-dependent optical properties of colloidal PbS quantum dots.
Iwan Moreels,Karel Lambert,Dries Smeets,David De Muynck,Tom Nollet,José C. Martins,Frank Vanhaecke,André Vantomme,Christophe Delerue,Guy Allan,Zeger Hens +10 more
TL;DR: At high energies, the molar extinction coefficient epsilon increases with the Qdot volume d(3) and agrees with theoretical calculations using the Maxwell-Garnett effective medium theory and bulk values for the Q dot dielectric function.
Journal ArticleDOI
The Role of Ligands in the Chemical Synthesis and Applications of Inorganic Nanoparticles.
Amelie Heuer-Jungemann,Neus Feliu,Neus Feliu,Ioanna Bakaimi,Majd A. Hamaly,Alaaldin M. Alkilany,Alaaldin M. Alkilany,Indranath Chakraborty,Atif Masood,Maria Francesca Casula,Athanasia Kostopoulou,Eunkeu Oh,Kimihiro Susumu,Michael H. Stewart,Igor L. Medintz,Emmanuel Stratakis,Wolfgang J. Parak,Antonios G. Kanaras +17 more
TL;DR: This article analyzes the interaction of nanoparticle surface and ligands with different chemical groups, the types of bonding, the final dispersibility of ligand-coated nanoparticles in complex media, their reactivity, and their performance in biomedicine, photodetectors, photovoltaic devices, light-emitting devices, sensors, memory devices, thermoelectric applications, and catalysis.
Journal ArticleDOI
Size-dependent valence and conduction band-edge energies of semiconductor nanocrystals.
TL;DR: This work investigates the size-dependent valence and conduction band-edge energies of CdSe, CdTe, PbS, and PbSe semiconductor quantum dots (QDs) through the use of photoelectron spectroscopy in air (PESA).
Journal ArticleDOI
The Influence of Carboxyl Groups on the Photoluminescence of Mercaptocarboxylic Acid-Stabilized CdTe Nanoparticles
TL;DR: In this paper, the pH-dependent photoluminescence (PL) of MPA-and TGA-stabilized CdTe nanoparticles was systematically investigated before and after addition of poly(acrylic acid) (PAA) into the CdTE solutions.
References
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Book
Optical Processes in Semiconductors
TL;DR: Optical processes in semiconductors as mentioned in this paper, Optical Process in Semiconductors (OPP), Optical Process of Semiconductor (OPS) and Optical Process (OPI)
Journal ArticleDOI
Quantum Semiconductor Structures
Book ChapterDOI
Quantum Size Effects in Layered Semiconductor Colloids
M. W. Peterson,Arthur J. Nozik +1 more
TL;DR: In this article, the formation of colloidal particles in the quantum-size regime (25 to 200 A) has been reported for eight semiconductors with layered structures, i.e., HgI2, BiI3, PbI2 and Bi2S3 Sb 2S3, MoS2, WSe2 and WS2.