scholarly journals Exciton States in Free-Standing and Embedded Semiconductor Nanocrystals

10.5772/36679 ◽  
2012 ◽  
Author(s):  
Yuriel Nez ◽  
Mikhail I. ◽  
Erick M. ◽  
Carlos Trallero-Giner
Keyword(s):  
Semiconductor Nanocrystals ◽  
Free Standing

Synthesis and Characterization of III-V Rod Shape Semiconductor Nanocrystals

2005 ◽  
Vol 494 ◽  
pp. 121-128
Author(s):  
J.M. Nedeljković ◽  
O.I. Mićić ◽  
S.P. Ahrenkiel ◽  
A.J. Nozik
Keyword(s):  
Size Distribution ◽  
Semiconductor Nanocrystals ◽  
Synthesis And Characterization ◽  
Lateral Growth ◽  
Narrow Size Distribution ◽  
Free Standing ◽  
Quantum Rods ◽  
Metallic Catalyst ◽  
Strong Confinement

InP and InAs quantum rods were synthesized via the reactions of monodispersed indium droplets with phosphide or arsenide ions, respectively. In these reactions indium droplets, which do not act as a catalyst but rather as a reactant, are completely consumed. For the synthesis of InP and InAs quantum rods with a narrow size distribution, a narrow size distribution of indium particles is required because each indium droplet serves as a template to strictly limit the lateral growth of individual InP or InAs nanocrystals. Free-standing InP (130 Å diameter and 870 Å length) and InAs (180 Å diameter and 745 Å length) quantum rods without residual metallic catalyst at the rod tip were synthesized from the diluted transparent solutions of metallic indium. Both kinds of synthesized nanorods are in the strong confinement regime since the Bohr diameters of InP and InAs are 200 and 700 Å, respectively.

scholarly journals Environmental release of core–shell semiconductor nanocrystals from free-standing polymer nanocomposite films

2016 ◽  
Vol 3 (3) ◽  
pp. 657-669 ◽  
Author(s):  
Karthik V. Pillai ◽  
Patrick J. Gray ◽  
Chun-Chieh Tien ◽  
Reiner Bleher ◽  
Li-Piin Sung ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Particle Size ◽  
Size Dependence ◽  
Semiconductor Nanocrystals ◽  
Polymer Nanocomposite ◽  
Nanocomposite Films ◽  
Core Shell ◽  
Free Standing ◽  
New Approach

This work presents a new approach to study mechanisms and particle-size dependence of environmental release of nanoparticles from polymer nanocompsites using fluorescent quantum dots.

Body balance in a free-standing position in road and off-road cyclists

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Paulina Hebisz ◽  
Rafal Hebisz ◽  
Marek Zaton
Keyword(s):  
Sagittal Plane ◽  
Standing Position ◽  
The Body ◽  
Free Standing ◽  
Body Balance ◽  
Eyes Closed ◽  
Road Cycling ◽  
Progressive Exercise ◽  
Before And After ◽  
Road Cyclists

AbstractBackground: The purpose of this study was to compare body balance in road and off-road cyclists, immediately before and after the racing season.Material/Methods: Twenty individuals participated in the study and they were divided into two groups: specialists in road-cycling (n = 10) and in off-road cycling (n = 10). Immediately before and after the five-month racing season stabilographic trials were carried out (at rest and after progressive exercise). In assessing body balance the distance and velocity of the centre shifts (in the anterior-posterior and left-right direction) were analysed. The tests were performed with the cyclists’ eyes open, eyes closed, and in feedback.Results: After the racing season, in the off-road cyclists’ group, distance and velocity of the centre of pressure shifts increased after a progressive exercise.Conclusions: In the off-road cyclists’ group the balance of the body in the sagittal plane deteriorated after the racing season. Moreover, after the racing season off-road cyclists were characterized by a worse balance of the body, compared to road cyclists

Wrinkling Poly(trimethylene 2,5-Furanoate) Free-standing Films: Nanostructure Formation and Physical Properties

2020 ◽  
Author(s):  
Michelina Soccio ◽  
Nadia Lotti ◽  
Andrea Munari ◽  
Esther Rebollar ◽  
Daniel E Martínez-Tong
Keyword(s):  
Irradiation Time ◽  
Polymer Surface ◽  
Laser Source ◽  
Free Standing ◽  
Force Microscopy ◽  
Nanostructure Formation ◽  
Physicochemical Changes ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

<p>Nanostructured wrinkles were developed on fully bio-based poly(trimethylene furanoate) (PTF) films by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We investigated the effect of irradiation time on wrinkle formation using an UV pulsed laser source, at a fluence of 8 mJ/cm2. It was found that the pulse range between 600 and 4800 pulses allowed formation of periodic nanometric ripples. The nanostructured surface was studied using a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic physicochemical properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethyleneterephthalate), PET, and poly(trimethyleneterephthalate), PTT. The surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by nanomechanical force spectroscopy measurements. In particular, an increased Young’s modulus and higher stiffness for the nanostructured sample were measured. <br></p>

Ultrastrong, Free-Standing and Large Nanofilms of Pyrenearamid

2019 ◽  
Author(s):  
Amalia Rapakousiou ◽  
Alejandro López-moreno ◽  
Belén Nieto-Ortega ◽  
M. Mar Bernal ◽  
Miguel A. Monclús ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Building Block ◽  
Aromatic Polyamide ◽  
Free Standing ◽  
Spatial Confinement ◽  
Polymeric Structure ◽  
Reduced Modulus ◽  
Organizational Arrangement ◽  
Polycyclic Aromatic ◽  
Nanoscale Building Block

We introduce poly(1,6-pyrene terephthalamide) polymer (PPyrTA) as an aromatic polyamide analogue of poly(p-phenylene terephthalamide) (PPTA), also known as Kevlar®. This work shows that the incorporation of polycyclic aromatic pyrene moieties improves drastically the mechanical properties of the polymeric structure, increasing elastic nanoindentation-determined modulus and hardness by factors of 1.9 and 4.3, respectively. Liquid deprotonated dispersions of PPyrTA nanofibers were used as nanoscale building block for producing large-surface, free-standing polymer macroscopic nanofilms. This 2D assembly leads to further significant improvements in reduced modulus and hardness (more than twice) compared to the starting polymer macroscale fibres, due to a better re-organizational arrangement of the PPyrTA nanofibers in the nanofilms, formed under 2D spatial confinement.

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