Quantum size dependence of femtosecond electronic dephasing and vibrational dynamics in CdSe nanocrystals

1994 ◽  
Vol 49 (20) ◽  
pp. 14435-14447 ◽  
Author(s):  
D. M. Mittleman ◽  
R. W. Schoenlein ◽  
J. J. Shiang ◽  
V. L. Colvin ◽  
A. P. Alivisatos ◽  
...  
2008 ◽  
Vol 1102 ◽  
Author(s):  
Chien-Tsung Wang ◽  
Chung-Hsiao Yeh

AbstractIn the study, semiconductor quantum dots (QDs) of CdSe nanocrystals have been demonstrated effective as the light energy harvesting assemblies in solar cells. Colloidal CdSe QDs were synthesized by the one-pot approach and linked through a surface modifier onto titania (TiO2) nanoparticles. The TiO2-CdSe composite, while employed as the photoanode in a photoelectrochemical apparatus, exhibited a higher photon-to-electron conversion efficiency (3-fold) than the TiO2 alone, and also a higher stability for photocurrent generation, according to photocurrent transient responses. The optical absorbance and photoluminescence of the CdSe colloid showed a blue shift in the absorption edge with decreasing the particle size (band energy gap shifts from 2.0 to 2.19 eV), suggesting a quantum size effect. The CdSe particle size was determined up to 5 nm by a transmission electron microscopy. A scheme describing the charge carrier rectification for the coupled semiconductor system is proposed.


1993 ◽  
Vol 70 (7) ◽  
pp. 1014-1017 ◽  
Author(s):  
R. W. Schoenlein ◽  
D. M. Mittleman ◽  
J. J. Shiang ◽  
A. P. Alivisatos ◽  
C. V. Shank

1999 ◽  
Vol 571 ◽  
Author(s):  
M. Jacobsohn ◽  
U. Banin

ABSTRACTSecond Harmonic Generation in CdSe nanocrystal quantum dots is observed by Hyper-Rayleigh scattering. We use a Ti-Sapphire femtosecond laser at 820 nm to induce the nonlinear optical response of the nanocrystals in solution. The unit cell normalized second harmonic coefficient βn, shows a substantial systematic enhancement in small sizes. The observed size dependence of the second harmonic generation process, is explained assuming two contributions. The first is a bulk-like contribution, from the non-centrosymmetric nanocrystal core, and the second, a contribution from the particle surface. The latter contribution is most significant in small nanocrystals with a substantial proportion of surface atoms.


1996 ◽  
Vol 197 (2-3) ◽  
pp. 238-246 ◽  
Author(s):  
L. Saviot ◽  
B. Champagnon ◽  
E. Duval ◽  
I.A. Kudriavtsev ◽  
A.I. Ekimov

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
H. Gordillo ◽  
I. Suárez ◽  
R. Abargues ◽  
P. Rodríguez-Cantó ◽  
S. Albert ◽  
...  

In this paper we review our recent progress in a still young type of active waveguides based on hybrid organic (polymer)—inorganic (semiconductor quantum dots) materials. They can be useful for the implementation of new photonic devices, because combining the properties of the semiconductor nanostructures (quantum size carrier confinement and temperature independent emission) with the technological capabilities of polymers. These optical waveguides can be easily fabricated by spin-coating and UV photolithography on many substrates (SiO2/Si, in the present work). We demonstrate that it is possible to control the active wavelength in a broad range (400–1100 nm), just by changing the base quantum dot material (CdS, CdSe, CdTe and PbS, but other are possible), without the necessity of changing fabrication conditions. Particularly, we have determined the optimum conditions to produce multi-color photoluminescence waveguiding by embedding CdS, CdSe and CdTe quantum dots into Poly(methyl methacrylate). Finally, we show new results regarding the incorporation of CdSe nanocrystals into a SU-8 resist, in order to extrapolate the study to a photolithographic and technologically more important polymer. In this case ridge waveguides are able to confine in 2D the light emitted by the quantum dots.


Nano Letters ◽  
2013 ◽  
Vol 14 (1) ◽  
pp. 353-358 ◽  
Author(s):  
Alicia W. Cohn ◽  
Jeffrey D. Rinehart ◽  
Alina M. Schimpf ◽  
Amanda L. Weaver ◽  
Daniel R. Gamelin

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