scholarly journals Green Light Emission ofZnxCd1-xSeNanocrystals Synthesized by One-Pot Method

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shu-Ru Chung ◽  
Kuan-Wen Wang ◽  
Hong-Shuo Chen
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Light Emission ◽  
Green Light ◽  
Particle Size Effect ◽  
Partial Replacement ◽  
Face Centered Cubic ◽  
One Pot ◽  
Zn Content ◽  
High Emission

We present a facile one-pot synthesis to prepare ternaryZnxCd1-xSe(x= 0.2, 0.5, 0.8, and 1) nanocrystals (NCs) with high emission quantum yield (QY, 45~89%). The effect of Zn content (x) ofZnxCd1-xSeNCs on their physical properties is investigated. The NCs have a particle size of 3.2 nm and face centered cubic structure. However, the actual compositions of the NCs are Zn0.03Cd0.97Se, Zn0.11Cd0.89Se, and Zn0.38Cd0.62Se when Zn content is 0.2, 0.5, and 0.8, respectively. In terms of the optical properties, the emission wavelength shifts from 512 to 545 nm with increasing Zn content from 0 to 0.8 while the QY changes from 89 to 45, respectively. Partial replacement of Cd by Zn is beneficial to improve the QY of Zn0.2and Zn0.5NCs. The optical properties of ternary NCs are affected by compositional effect rather than particle size effect.

Particle size effect on structural and optical properties of Y2O3:Nd3+ nanoparticles prepared by coconut water-assisted sol-gel route

2018 ◽  
Vol 200 ◽  
pp. 43-49 ◽  
Author(s):  
Maria A. Gomes ◽  
Antônio Carlos Brandão-Silva ◽  
Jhon F.M. Avila ◽  
Márcio A.R.C. Alencar ◽  
José J. Rodrigues ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Size Effect ◽  
Sol Gel ◽  
Particle Size Effect ◽  
Coconut Water ◽  
Structural And Optical Properties

STRUCTURAL, ELECTRICAL AND OPTICAL PROPERTIES OF TiO2THIN FILM DEPOSITED ON THE NANO POROUS SILICON TEMPLATE

2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850017
Author(s):  
MAHMOOD BAHAR ◽  
ENSIEH KHALILI DERMANI
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Porous Silicon ◽  
Light Emission ◽  
Electrochemical Etching ◽  
Green Light ◽  
Blue Emission ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Green Light Emission

The porous silicon (PSi), which is produced by the electrochemical etching, has been used as a substrate for the growth of the titanium oxide (TiO2) thin films. By using the EBPVD method, TiO2thin films have been deposited on the surface of the PSi substrate. TiO2/PSi layers were annealed at the temperature of 400[Formula: see text]C, 500[Formula: see text]C and 600[Formula: see text]C for different tests. The morphology and structures of layers were investigated by the scanning electron microscopy (SEM) and X-ray diffraction (XRD). The current–voltage characteristic curves of samples and the ideality factor of heterojunction were studied. The results showed that the electrical properties of the samples change with increase in the annealing temperature. The optical properties of the prepared samples were investigated by using UV–Vis and photoluminescence (PL) spectroscopy. Green light emission of the PSi combined with the blue light and violet–blue emission obtained from the TiO2/PSi PL spectra. The results showed that the optical band gap energy of the PSi has increased from 1.86[Formula: see text]eV to 2.93[Formula: see text]eV due to the deposition of TiO2thin film.

scholarly journals Green Synthesis of Highly Luminescent Carbon Quantum Dots from Lemon Juice

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Bui Thi Hoan ◽  
Phuong Dinh Tam ◽  
Vuong-Hung Pham
Keyword(s):  
Photoelectron Spectroscopy ◽  
Light Emission ◽  
Green Light ◽  
Carbon Quantum Dots ◽  
Lemon Juice ◽  
One Pot ◽  
Transmission Electron ◽  
Green Light Emission ◽  
Different Temperatures ◽  
The One

Highly luminescent carbon dots (C-dots) were synthesized by the one-pot simple hydrothermal method directly from lemon juice using different temperatures, time, aging of precursors, and diluted solvents to control the luminescence of C‐dots. The obtained C-dots were characterized by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectrophotometry, dynamic light scattering, ultraviolet-visible spectrophotometry, and photoluminescent spectrophotometry. The results show that C‐dots had strong green light emission with quantum yield in the range of 14.86 to 24.89% as a function of hydrothermal temperatures. Furthermore, light emission that is dependent on hydrothermal time, aging of precursor, and diluted solvent was observed. These results suggest that the C‐dots have potential application in optoelectronics and bioimaging.

scholarly journals Facile Fabrication of Fluorescent Inorganic Nanoparticles with Diverse Shapes for Cell Imaging

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 154
Author(s):  
Guifang Wang ◽  
Jing Wang ◽  
Linlin Zhao ◽  
Qiang Zhang ◽  
Yan Lu
Keyword(s):  
Cell Imaging ◽  
Light Emission ◽  
Sol Gel ◽  
Green Light ◽  
Spherical Shape ◽  
Inorganic Nanoparticles ◽  
Model Systems ◽  
One Pot ◽  
Sio2 Shell ◽  
Different Shapes

In the present work, we describe a facile and general method of fabricating fluorescent inorganic nanoparticles with diverse shapes for cell imaging application. The hematite (α-Fe2O3) nanoparticles (HNPs) with three different shapes (i.e., spindle shape, ellipsoidal shape and quasi-spherical shape) were first prepared as model systems in consideration of good biocompatibility and the controllable morphology of α-Fe2O3. Three fluorescent HNPs with different shapes were readily achieved via one-pot sol-gel reaction of AIE luminogen-functionalized siloxane (AIEgen-Si(OCH3)3) and TEOS in the presence of PVP-stabilized HNPs. Due to the fluorescence originating from the thin AIEgens-contained SiO2 shell around the HNPs, their photoluminescent intensities can be tuned by changing the concentrations of TEOS and AIEgen-Si(OCH3)3 in feed prior to the sol-gel reaction. When the as-prepared fluorescent products were dispersed in water, they gave intense green light emission upon excitation at 360 nm with relatively high fluorescence quantum yield. Further, fluorescent HNPs exhibited low cytotoxicity and excellent photostability and, thus, were used as optical probes to preliminarily explore the effect of nanoparticle shapes on their cellular uptake behaviors. This work should open a facile way to prepare various fluorescent inorganic nanoparticles with specific morphology for various biological applications.

Determination of particle size distribution of water-soluble CdTe quantum dots by optical spectroscopy

RSC Advances ◽  
2014 ◽  
Vol 4 (68) ◽  
pp. 36024-36030 ◽  
Author(s):  
J. C. L. Sousa ◽  
M. G. Vivas ◽  
J. L. Ferrari ◽  
C. R. Mendonca ◽  
M. A. Schiavon
Keyword(s):  
Quantum Dots ◽  
Particle Size ◽  
Optical Properties ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Water Soluble ◽  
Cdte Quantum Dots ◽  
One Pot ◽  
The One

In the present study, we report the synthesis of glutathione (GSH) capped CdTe quantum dots (QDs) using the one-pot approach as well as their optical properties.

Conductivity, photoconductivity and optical properties of amorphous GaN films

2001 ◽  
Vol 693 ◽  
Author(s):  
A. Koo ◽  
U. D. Lanke ◽  
B. J. Ruck ◽  
S. A. Brown ◽  
R. Reeves ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Light Emission ◽  
Visible Region ◽  
Green Light ◽  
Complex Form ◽  
Room Temperature Resistivity ◽  
Low Density ◽  
Preparation Conditions ◽  
Gap States

AbstractIt has been predicted that amorphous GaN has a low density of states in the gap, and therefore has potential as a useful opto-electronic material in the blue-green spectral region. We have synthesised amorphous GaN films on various substrates by ion assisted deposition and investigated the effects of sample preparation conditions on the conducting and optical properties. The room temperature resistivity ρ0 of stoichiometric (Ga:N of 1:1) films is above 105 Ω cm, and these films exhibit a complex form for the temperature dependence of the resistivity. Films having an excess of Ga show a much lower ρ0. The optical absorption shows ar 0 band-gap of 3 eV, with the gap falling below that value when the amorphous network incorporates homopolar (Ga-Ga) bonds. The best films are thus transparent across the visible region with a low density of gap states, undetectable in optical absorption. The photoluminescence spectra obtained from these a-GaN films consist of a broad green light emission peaking at 528 nm. Preliminary photoconductivity measurements show sensitivity in the UV.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Fluorescent Nanotechnology: An Evolution in Optical Sensors

2020 ◽  
Vol 17 ◽  
Author(s):  
Dilawar Hassan ◽  
Hadi Bakhsh ◽  
Asif M. Khurram ◽  
Shakeel A. Bhutto ◽  
Nida S. Jalbani ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Sensors ◽  
Light Emission ◽  
Environmental Contaminants ◽  
Fluorescent Nanoparticles ◽  
Sensing Applications ◽  
Properties Of Materials ◽  
Optical Properties Of Materials ◽  
Fluorescent Nanomaterials

Background: The optical properties of nanomaterials have evolved enormously with the introduction of nanotechnology. The property of materials to absorb and/or emit specific wavelength has turned them into one of the most favourite candidates to be effectively utilized in different sensing applications e.g organic light emission diodes (OLEDs) sensors, gas sensors, biosensors and fluorescent sensors. These materials have been reported as a sensor in the field of tissue and cell imaging, cancer detection and detection of environmental contaminants etc. Fluorescent nanomaterials are heling in rapid and timely detection of various contaminants that greatly impact the quality of life and food, that is exposed to these contaminants. Later, all the contaminants have been investigated to be most perilous entities that momentously affect the life span of the animals and humans who use those foods which have been contaminated. Objective: In this review, we will discuss about various methods and approaches to synthesize the fluorescent nanoparticles and quantum dots (QDs) and their applications in various fields. The application will include the detection of various environmental contaminants and bio-medical applications. We will discuss the possible mode of action of the nanoparticles when used as sensor for the environmental contaminants as well as the surface modification of some fluorescent nanomaterials with anti-body and enzyme for specific detection in animal kingdom. We will also describe some RAMAN based sensors as well as some optical sensing-based nanosensors. Conclusion: Nanotechnology has enabled to play with the size, shape and morphology of materials in the nanoscale. The physical, chemical and optical properties of materials change dramatically when they are reduced to nanoscale. The optical properties can become choosy in terms of emission or absorption of wavelength in the size range and can result in production of very sensitive optical sensor. The results show that the use of fluorescent nanomaterials for the sensing purposes are helping a great deal in the sensing field.

scholarly journals Synthesis and Optical Properties of B-Mg co-Doped ZnO Nanoparticles

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 882
Author(s):  
Yuechan Li ◽  
Yongli Li ◽  
An Xie
Keyword(s):  
Optical Properties ◽  
Zno Nanoparticles ◽  
Great Influence ◽  
Structure Study ◽  
Band Gap Energy ◽  
One Pot ◽  
Gap Energy ◽  
Doping Impurity ◽  
Shrinkage Effect ◽  
Co Doped

Doping impurity into ZnO is an effective and powerful technique to tailor structures and enhance its optical properties. In this work, Zn1−xMgxO and Zn1−x−yMgxByO nanoparticles (x = 0, 0.1, 0.2, 0.3, 0.4; y = 0, 0.02, 0.04) were synthesized via one-pot method. It shows that the Mg and B dopants has great influence on crystallinity and surface morphology of ZnO nanoparticles, without changing the wurtzite structure of ZnO. The band structure study indicates that the competition of Conductive Band (CB) shift, Burstein–Moss (B-M) shift and Shrinkage effect will cause the band gap energy change in ZnO.

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