scholarly journals Development of Quantum Dot (QD) Based Color Converters for Multicolor Display

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1089
Author(s):  
Muhammad T. Sajjad ◽  
Ashu K. Bansal ◽  
Francesco Antolini ◽  
Eduard Preis ◽  
Lenuta Stroea ◽  
...  
Keyword(s):  
Polymer Matrix ◽  
Cost Effective ◽  
Final Size ◽  
Force Microscopy ◽  
Morphological Studies ◽  
Color Displays ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Color Conversion ◽  
Temperature Time

Many displays involve the use of color conversion layers. QDs are attractive candidates as color converters because of their easy processability, tuneable optical properties, high photoluminescence quantum yield, and good stability. Here, we show that emissive QDs with narrow emission range can be made in-situ in a polymer matrix, with properties useful for color conversion. This was achieved by blending the blue-emitting pyridine based polymer with a cadmium selenide precursor and baking their films at different temperatures. To achieve efficient color conversion, blend ratio and baking temperature/time were varied. We found that thermal decomposition of the precursor leads to highly emissive QDs whose final size and emission can be controlled using baking temperature/time. The formation of the QDs inside the polymer matrix was confirmed through morphological studies using atomic force microscopy (AFM) and transmission electron microscopy (TEM). Hence, our approach provides a cost-effective route to making highly emissive color converters for multi-color displays.

scholarly journals Glittering ZnO/Ag/MnO Nano Superstructures for Photocatalytic Applications

2020 ◽  
Vol 32 (10) ◽  
pp. 2453-2459
Author(s):  
J.P. Shubha ◽  
S. Shwetha Priyadharshini ◽  
S. Jayadev
Keyword(s):  
Electron Microscopy ◽  
Cost Effective ◽  
Zinc Nitrate ◽  
Ion Concentration ◽  
Manganese Acetate ◽  
Blue Dye ◽  
Hydrogen Ion Concentration ◽  
Morphological Studies ◽  
Transmission Electron ◽  
Green Route

ZnO/Ag/MnO ternary heterostructure nanomaterials have been synthesized via cost effective green route using zinc nitrate, manganese acetate and silver nitrate as oxidizers and perished curd as a fuel. The obtained ZnO/Ag/MnO nanomaterials are analyzed using Powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), morphological studies by scanning electron microscopy (FESEM), internal structure by transmission electron microscopy (TEM). Both PXRD and FESEM techniques were used to confirm the formation of particles and flakes composition of ZnO/Ag/MnO nanomaterials. Photocatalytic activity of ZnO/Ag/MnO was assessed by varying light source, hydrogen ion concentration, amount of catalyst and amount of dye. The ZnO/Ag/MnO nanoparticles exhibited an enhanced photodegradation of methylene blue dye under visible light.

Optimization of UHV-CVD Thin Films for Gate Dielectric Applications

2006 ◽  
Vol 45 ◽  
pp. 1351-1354
Author(s):  
Bridget R. Rogers ◽  
Zhe Song ◽  
Robert D. Geil ◽  
Robert A. Weller
Keyword(s):  
Silicon Oxide ◽  
Gate Dielectric ◽  
High Surface ◽  
Ex Situ ◽  
Oxide Surfaces ◽  
Layer By Layer ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Initial Stage ◽  
Different Temperatures

In-situ and ex-situ spectroscopic ellipsometry (SE), atomic force microscopy (AFM), transmission electron microscopy (TEM), and time of flight medium energy backscattering (ToF MEBS), are used to investigate the properties of 30 and 60 Å ZrO2 films deposited at different temperatures on hydrogen terminated silicon (H-Si) and native silicon oxide surfaces. Results show that the initial-stage deposition of ZrO2 on H-Si and native silicon oxide surfaces are different. A 3-dimesional (3D) type nucleation process of ZrO2 on H-Si leads to high surface roughness films, while layer-by-layer deposition on native silicon oxide surfaces leads to smooth, uniform ZrO2 films. An interfacial layer, between the substrate and the metal oxide, is formed through two independent mechanisms: reaction between the starting surfaces and ZTB or its decomposition intermediates, and diffusion of reactive oxidants through the forming ZrO2 interfacial stack layer to react with the substrate.

Behavior of Dopant-Related Defects in AlGaAs Superlattices

1989 ◽  
Vol 163 ◽  
Author(s):  
N.D. Theodore ◽  
P. Mei ◽  
S.A. Schwarz ◽  
C.B. Carter ◽  
C. Palmstrom ◽  
...  
Keyword(s):  
Time Behavior ◽  
Dislocation Loops ◽  
Silicon Doping ◽  
Transmission Electron ◽  
Mixing Behavior ◽  
High Resolution Tem ◽  
Different Temperatures ◽  
Time Periods ◽  
Silicon Doped ◽  
Temperature Time

AbstractDuring the course of investigation of the mixing of highly silicon-doped GaAs/AlAs superlattices, defects such as dislocation loops and Si-rich precipitates were found to form in the specimens. These defects formed at particular doping levels upon annealing of the samples. The presence of the defects can be related to changes in mixing behavior. In the present study, transmission electron microscopy has been used to characterize the defects. Superlattices with varying silicon doping levels were annealed at different temperatures for varying time-periods, to observe the temperature-time behavior of the dislocation loops. The defects aggregate preferentially in the GaAs as opposed to the AlAs in the superlattice. A number of the dislocation-loops were investigated using high-resolution TEM. All the loops observed were interstitial in nature.

Enhancing properties of polyvinyl alcohol film using sorghum starch nanocrystals – A cost effective filler from natural source

2017 ◽  
Vol 2 (2) ◽  
pp. 169 ◽  
Author(s):  
S. Vasantha Kumar ◽  
V. A. Sajeevkumar ◽  
Johnsy George ◽  
Sunny Kumar
Keyword(s):  
Food Packaging ◽  
Cost Effective ◽  
Natural Source ◽  
Nanocomposite Films ◽  
Poly Vinyl Alcohol ◽  
Force Microscopy ◽  
Morphological Studies ◽  
Atomic Force ◽  
Polyvinyl Alcohol Film ◽  
Starch Nanocrystals

<p>Poly Vinyl Alcohol (PVA) nanocomposite films with Sorghum Starch Nanocrystals (SSN) were prepared by incorporating various concentrations of SSN in PVA.  SSN was isolated using acid hydrolysis of sorghum starch.  The morphological studies of SSN using Atomic Force Microscopy (AFM) revealed that the particle size varied from 65 to 68 nm.  The mechanical properties of PVA-SSN nanocomposite films indicated an improvement in tensile strength and percentage elongation at break when compared to that of PVA films.  This can be attributed to the stronger interaction of PVA with SSN due to hydrogen bonding.  Besides this, PVA-SSN nanocomposite films also exhibited good thermal properties.  Thus, the use of SSN (a cost effective filler from natural source) imparted superior properties to the PVA nanocomposite films, which will be beneficial for applications such as food packaging. </p>

Thin Films of Titanium Dioxide Prepared by Chemical Routes using Novel Precursors

2002 ◽  
Vol 755 ◽  
Author(s):  
K. Shalini ◽  
S. Chandrasekaran ◽  
S.A. Shivashankar
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Film Growth ◽  
Anatase Phase ◽  
Chemical Vapor ◽  
Inert Atmosphere ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Transmission Electron ◽  
Different Temperatures

ABSTRACTNovel, volatile, stable, oxo-β-ketoesterate complexes of titanium, whose synthesis requires only an inert atmosphere, as opposed to a glove box, have been developed. Using one of the complexes as the precursor, thin films of TiO2 have been deposited on glass substrates by metalorganic chemical vapor deposition (MOCVD) at temperatures ranging from 400°C to 525°C and characterized by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. All the films grown in this temperature range are very smooth; those grown above 480°C consist of nearly monodisperse, nanocrystals of the anatase phase. Optical studies show the bandgaps in the range 3.4–3.7 eV for films grown at different temperatures. Thin films of anatase TiO2 have also been grown by spin-coating technique using another ketoesterate complex of titanium, demonstrating that the newly developed complexes can be successfully used for thin film growth by various chemical routes.

scholarly journals Graphite Nanosheet Exfoliation From Graphite Flakes Through Functionalization Using Phthalic Acid

2015 ◽  
Vol 60 (2) ◽  
pp. 1251-1255
Author(s):  
J.H. Kim ◽  
J.-H. Lee
Keyword(s):  
Phthalic Acid ◽  
Nitrogen Atmosphere ◽  
Graphite Nanosheets ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Graphite Nanosheet ◽  
Different Temperatures ◽  
Ft Ir ◽  
Ir Analysis

AbstractIn order to fabricate graphite nanosheets from graphite flakes, edge-functionalized graphite nanosheets were prepared by a functionalization method using phthalic acid as the molecule to be grafted. A polyphosphoric acid/P2O5solution containing graphite and phthalic acid were heated at different temperatures for 72 h in a nitrogen atmosphere. It was confirmed by transmission electron microscopy and atomic force microscopy that the resultant phthalic acid-functionalized graphite nanosheets had a large surface area of 20.69μm2in average and an average thickness of 1.39 nm. It was also found by X-ray diffractometry and Fourier transform infrared spectroscopy (FT-IR) analysis that the functionalization caused the formation of C=O bonds at the edges of the graphite nanosheets. The yield from this functionalization method was found to be dependent on the reaction temperature, only when it is between 70 and 130°C, because of the dehydration of phthalic acid at higher temperatures. This was confirmed by FT-IR analysis and the observation of low thermal energies at low temperatures.

Morphological studies of linear (AB)n multiblock copolymers and their blends

1992 ◽  
Vol 50 (1) ◽  
pp. 384-385
Author(s):  
Richard J. Spontak ◽  
Steven D. Smith ◽  
Arman Ashraf
Keyword(s):  
Electron Microscopy ◽  
Microphase Separation ◽  
Multiblock Copolymers ◽  
First Order ◽  
Morphological Studies ◽  
Transmission Electron ◽  
First Order Phase Transition ◽  
Covalently Bonded ◽  
Total Molecular Weight ◽  
First Order Phase

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

The Electrical Characterization and Physical Failure Analysis for Transistor Gate Leakage

2006 ◽  
Author(s):  
Tsung-Te Li ◽  
Chao-Chi Wu ◽  
Jung-Hsiang Chuang ◽  
Jon C. Lee
Keyword(s):  
Failure Analysis ◽  
Electrical Characterization ◽  
Physical Analysis ◽  
Gate Leakage ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Voltage Stress ◽  
Leakage Site

Abstract This article describes the electrical and physical analysis of gate leakage in nanometer transistors using conducting atomic force microscopy (C-AFM), nano-probing, transmission electron microscopy (TEM), and chemical decoration on simulated overstressed devices. A failure analysis case study involving a soft single bit failure is detailed. Following the nano-probing analysis, TEM cross sectioning of this failing device was performed. A voltage bias was applied to exaggerate the gate leakage site. Following this deliberate voltage overstress, a solution of boiling 10%wt KOH was used to etch decorate the gate leakage site followed by SEM inspection. Different transistor leakage behaviors can be identified with nano-probing measurements and then compared with simulation data for increased confidence in the failure analysis result. Nano-probing can be used to apply voltage stress on a transistor or a leakage path to worsen the weak point and then observe the leakage site easier.

Nanocomposite synthesis by thermolysis of [Ag(hfac)(COD)] in amorphous polystyrene

2012 ◽  
Vol 19 (2) ◽  
pp. 195-197 ◽  
Author(s):  
Gianfranco Carotenuto ◽  
Mariano Palomba ◽  
Luigi Nicolais
Keyword(s):  
Polymer Matrix ◽  
Nanocomposite Films ◽  
Numerical Density ◽  
Silver Particles ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Yellow Coloration ◽  
Color Filters ◽  
Silver Atoms

AbstractLightfast color filters (intensively and brightly colored) can be easily produced by dying optical plastics with the surface plasmon resonance (SPR) of metal nanoparticles such as silver and gold. Here, color filters based on silver nanoparticles embedded in amorphous polystyrene have been prepared by dissolving and thermally decomposing (1,5-cyclooctadiene)(hexafluoro-acetylacetonate)silver(I) in amorphous polystyrene. The metal precursor quickly decomposes (10 s, at 180°C), leading to silver atoms that clusterize and produce a non-aggregated dispersion of silver particles in the polymer matrix. The intensity of the yellow coloration due to the SPR of nanoscopic silver can be widely tuned simply by varying the cluster numerical density in the polymer matrix that depends on the silver precursor concentration. The obtained nanocomposite films have been characterized by X-ray power diffraction, transmission electron microscopy, and UV-Vis spectroscopy.

Sign in / Sign up

Export Citation Format

Share Document