scholarly journals SYNTHESIS AND OPTICAL PROPERTIES OF MESOMORPHIC GLASSY NANOCOMPOSITES BASED ON CADMIUM CAPRYLATE WITH CdSe / ZnS HETERONANOPARTICLES

2019 ◽  
Vol 85 (1) ◽  
pp. 13-18
Author(s):  
Tatiana Mirnaya ◽  
Galina Yaremchuk ◽  
Alexander Kosheliev
Keyword(s):  
Optical Properties ◽  
Liquid Crystalline ◽  
Spectral Characteristics ◽  
Fluorescence Band ◽  
Molar Ratio ◽  
Emission Region ◽  
Core Shell ◽  
Zns Nanoparticles ◽  
Long Wavelength ◽  
Wavelength Emission

The paper presents on the synthesis and optical properties of mesomorphic composites, based on a glassy liquid-crystalline caprylate matrix, with  CdSе/ZnS hetero-nanoparticles. The synthesis of complex core-shell semiconductor nanoparticles was carried out by fusing together a cadmium caprylate composite with CdSе nanoparticles and zinc caprylate composite with ZnS nanoparticles. The cadmium and zinc chalcogenide nanoparticles have been synthesized in molten cadmium caprylate and zinc caprylate respectively. It has been found by optical spectroscopy that the have hetero-nanoparticles a core-shell structure. The effect of the composition (molar ratio of the components) of CdSе/ZnS hetero-nanoparticles on their spectral characteristics has been studied. It has been shown that the nanocomposites with hetero-nanoparticles are characterized by a more intense exciton fluorescence band than composites with individual CdSе or ZnS nanoparticles. It has been found that by varying the hetero-nanoparticle composition, one can change the core-shell thickness ratio and adjust thereby the absorption and emission band edge. As the number of ZnS nanoparticles in CdSе/ZnS hetero-nanoparticles increases some narrowing of the long- wavelength emission region first takes plase, which may be attributed to a reduction in the recombination of the smaller number of surface trapped exciton, and then, at a large ZnS content, a broadening of the long- wavelength emission region takes plase due to the extended CdSе/ZnS surface. It has been found that the main  contribution to the exciton fluorescence of nanocomposites with CdSе/ZnS hetero-nanoparticles is made by cadmium selenide nanoparticles, and that zinc sulfide nanoparticles enhance exciton fluorescence, also due to decrease in surface emission. It has been shown that the nanocomposites with hetero-nanoparticles are characterized by a more intense exciton fluorescence band that the nanocomposites with individual CdSе. The highest emission is observed in the case of the 35-55 % ZnS content of the shell, and at a smaller or larger amount of ZnS, emission intensity decreases.  

Preparation and Characterization of the Core/Shell Structured of CdTe/Ni Fluorescent-Magnetic Particle

2011 ◽  
Vol 217-218 ◽  
pp. 216-219 ◽  
Author(s):  
Shi Chao Xu ◽  
Yue Qian Yang ◽  
Yan Shan Liu ◽  
Heng Miao ◽  
Mei Dong ◽  
...  
Keyword(s):  
Optical Properties ◽  
Hydrazine Hydrate ◽  
Magnetic Core ◽  
Red Shift ◽  
Nano Particles ◽  
Molar Ratio ◽  
Core Shell ◽  
Ni Nanoparticles ◽  
Dna Labeling ◽  
Dual Functional

The niclel nanoparticles were prepared via polyol process with hydrazine hydrate as reductant, the optimum conditions were investigated and proposed to be the molar ratio of NiCl2: NaOH: Hydrazine hydrate =1: 2: 11, 60 °C, pH5.5. The qualified fluorescent-magnetic dual functional CdTe/Ni nanoparticles were synthesized via layer-by-layer (LBL) technique, Ni was designed to be magnetic core and CdTe was used as fluorescent shell material, the molar ratio of CdTe:Ni is 4.5:1. The morphology of the Ni nano particles and CdTe/Ni core shell dual functional nano particles were characterized by transmission electron microscopy (TEM), and optical properties were investigated with fluorescence spectrum (FS) and ultra violet spectrum (UV). The synthesized CdTe/Ni nanoparticles showed yellow fluorescence when excited at 365nm, CdTe/Ni magnetic core shell QDs can be simply precipitated with a common magnet. TEM data indicated that ~15nm of Ni nanoparticles were obtained and ~25nm of CdTe/Ni core shell dual functional nanoparticles were prepared. Red shift of maximum absorbance peak was detected via UV, and these results inferred the QDs growth, moreover, 40nm red shift of maximum emission wavelength from 530nm to 570nm was observed, and which showed the growth QDs and formation of CdTe shell. The prepared magnetic core shell CdTe/Ni nanoparticles showed excellent optical properties, and it is expected to be useful and helpful in DNA sensing based on fluorescence resonance energy transfer, biological separating, and DNA labeling process.

Ag2S/ZnS nanocomposites: Synthesis, structure and optical properties

2020 ◽  
pp. 2150033
Author(s):  
M. A. Ramazanov ◽  
S. G. Nuriyeva ◽  
H. A. Shirinova ◽  
A. H. Karimova ◽  
M. A. Nuriyev
Keyword(s):  
Optical Properties ◽  
Structural Investigation ◽  
Emission Spectra ◽  
Structural Features ◽  
Core Shell ◽  
Zns Nanoparticles ◽  
Sem Images ◽  
X Ray ◽  
The Core ◽  
Novel Method

Ag2S/ZnS nanocomposites were synthesized using a novel method, and their structural features and optical properties were also investigated. For the structural investigation of the core/shell-like nanocomposites, X-ray powder diffraction technique (XRD) and scanning electron microscopy (SEM) were used. Optical features of Ag2S/ZnS nanocomposites were studied by UV-Vis absorption and photoluminescence spectroscopy (PL). According to the SEM images, the sizes of the Ag2S, ZnS nanoparticles and Ag2S/ZnS core/shell-like nanocomposites are in the region of the 10–15; 25–50 and 15–80 nm, respectively. Furthermore, the absorption spectroscopy indicates that the bandgap of Ag2S/ZnS nanocomposites is approximately 2.4 eV. By comparison of the intensities of the emission spectra, it was clear that the intensity of Ag2S/ZnS is much lower than that of ZnS.

Confined synthesis of carbon dots with tunable long-wavelength emission in a 2-dimensional layered double hydroxide matrix

Nanoscale ◽  
2020 ◽  
Vol 12 (14) ◽  
pp. 7888-7894 ◽  
Author(s):  
Wendi Liu ◽  
Ruizheng Liang ◽  
Yanjun Lin
Keyword(s):  
Optical Properties ◽  
Layered Double Hydroxide ◽  
Layered Double Hydroxides ◽  
Carbon Dots ◽  
Long Wavelength ◽  
Wavelength Emission ◽  
Double Hydroxide ◽  
Double Hydroxides

CDs with gradual modulation in structures and optical properties can be obtained through a confined reaction in 2-dimentsonal layered double hydroxides.

Synthesis, Characterization, and Optical Properties of Near-Infrared Reflecting Composite Inorganic Pigments Composed of TiO2/CuO Core–Shell Particles

2018 ◽  
Vol 71 (5) ◽  
pp. 373 ◽  
Author(s):  
Bolong Yao ◽  
Siyao Geng ◽  
Jie Wang ◽  
Likui Wang
Keyword(s):  
Electron Microscopy ◽  
Optical Properties ◽  
Near Infrared ◽  
Diffuse Reflectance Spectroscopy ◽  
Infrared Region ◽  
Molar Ratio ◽  
Core Shell ◽  
Near Infrared Reflectance ◽  
Cu Content ◽  
Solar Reflectance

Pigments with dark appearance and high solar energy reflectance are of great application value. In the present work, dark grey composite pigments with a TiO2/CuO core–shell structure were prepared through calcination of precursors obtained from the precipitation of Cu(OH)2 on TiO2 particles. The composition, structure, and optical properties of the synthesised powders were characterised by colourimetry, near-infrared diffuse reflectance spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The pigments are composed of rutile TiO2 and tenorite CuO, and the powder colour changes from white to dark grey as the Cu content increases. With a molar ratio of CuO to TiO2 of 0.6, the pigment presents optimal colour (a* = 1.66, b* = −2.19, L* = 52.37) and optical performance. The near-infrared reflectance, the solar reflectance in the near-infrared region, and the total solar reflectance reach 87.2, 70.6, and 37.2 %, respectively. Furthermore, it is demonstrated that the composite pigments exhibit a deeper colour and higher reflectivity than conventional dark-blended powders. These cool dark pigments could be applied in the coatings for buildings (roofs and walls) to improve building comfortability and reduce cooling energy consumption.

Optical Properties and Liquid-Crystalline Behaviors of Cyclosiloxane-Based Oligomer Films

2011 ◽  
Vol 391-392 ◽  
pp. 1179-1182
Author(s):  
Fan Bao Meng ◽  
Hong Mei Gao ◽  
Cui Zhi Zhu ◽  
Ri Li ◽  
Xiao Yan Lin
Keyword(s):  
Optical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Liquid Crystalline ◽  
Cholesteric Phase ◽  
Polymer Systems ◽  
Long Wavelength ◽  
Chemical Structures ◽  
Temperature Ranges ◽  
Synthesized Materials

A series of liquid crystalline (LC) oligomer films (IP-VP) were prepared by use of cyclo(tetramethylhydrogeno)siloxane (CTMHS), and two different cholesteric monomers that possess ortho- or para-substituted benzene. The chemical structures, liquid-crystalline properties and optical properties of the synthesized materials were characterized by various experimental techniques. All the samples showed cholesteric phase with very wide mesophase temperature ranges. From IP to VP, the glass transition temperature and the isotropic temperature decreased slightly with increase of C2PB component in the polymer systems. The maximum reflection bands shift to long wavelength from IP to VP, suggesting the helical pitch become longer with more ortho-substituted benzene in the polymer systems

scholarly journals Synthesis and optical properties of new 4-substituted pyrimidines - D-A type chromophores

2021 ◽  
Vol 11 (2) ◽  
pp. 139-153
Author(s):  
Elena S. Drachjova ◽  
◽  
Tatyana V. Shavrina ◽  
Elena V. Shklyaeva ◽  
Georgy G. Abashev ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electrochemical Properties ◽  
Band Gap ◽  
Band Gap Energy ◽  
Long Wavelength ◽  
Gap Energy ◽  
Emission Maximum ◽  
Thiophene Moiety ◽  
Wavelength Emission

The set of 4-aryl(hetaryl)pyrimidines, where aryl/hetaryl is a highly electron donating substituent was synthesized. Optical and electrochemical properties of the synthesized compounds were studied and the values of a forbidden band gap energy ( ) were determined. The narrowest bandgap was found to be inherent to 4-ferrocenylpyrimidine (1.8 eV) and the most long-wavelength emission maximum ‑ to para-substituted pyrimidine which structure embeds a thiophene moiety between N-hexylcarbazolyl fragment and the pyrimidine core (577 нм).

Self-Assembly Optical Components

2003 ◽  
Vol 771 ◽  
Author(s):  
Pavel I. Lazarev ◽  
Michael V. Paukshto ◽  
Elena N. Sidorenko
Keyword(s):  
Optical Properties ◽  
Self Assembly ◽  
Crystalline State ◽  
Liquid Crystalline ◽  
Film Deposition ◽  
X Ray Diffraction ◽  
Optical Components ◽  
Crystal Film ◽  
Solid Film ◽  
Thin Crystal

AbstractWe report a new method of Thin Crystal Film deposition. In the present paper we describe the method of crystallization, structure, and optical properties of Bisbenzimidazo[2,1-a:1',2',b']anthra[2,1,9-def:6,5,10-d'e'f']-diisoquinoline-6,9-dion (mixture with cis-isomer) (abbreviated DBI PTCA) sulfonation product. The Thin Crystal Film has a thickness of 200-1000 nm, with anisotropic optical properties such as refraction and absorption indices. X-ray diffraction data evidences a lyotropic liquid crystalline state in liquid phase and crystalline state in solid film. Anisotropic optical properties of the film make it useful in optical devices, e.g. liquid crystal displays.

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