scholarly journals Оптические свойства нанокластеров серебра, синтезированных в поверхностно-привитой полиакриловой кислоте при разных плотностях прививки

2019 ◽  
Vol 126 (2) ◽  
pp. 220
Author(s):  
А.А. Горбачев ◽  
Н.И. Сушко ◽  
П.П. Першукевич ◽  
О.Н. Третинников

AbstractFluorescent silver nanoclusters immobilized on a plastic substrate are obtained by photoinduced template synthesis using polyacrylic acid chemically grafted to the substrate surface as a template. The electronic absorption and fluorescence spectra of nanoclusters are studied depending on the polyacrylic acid grafting density. It is found that the optical absorption and fluorescence intensities of nanoclusters monotonically increase with increasing grafting density. The position and shape of the absorption and emission spectra almost do not change. The higher the polymer template grafting density, the higher the fluorescence stability of samples during storage at room temperature.

2012 ◽  
Vol 557-559 ◽  
pp. 1031-1036 ◽  
Author(s):  
Jian Xin Yang ◽  
Xiang Hui Wang

A series of fluorescence compounds, 4-benzofuranyl-1,8-naphthalimides, were prepared through cycloaddition reaction from 4-ethynyl-1,8-naphthalimides and o-iodophenols which catalyzed by a Pd(PPh3)2Cl2 / CuI system under mild conditions. The intermediate material, 4-ethynyl-1,8- naphthalimide, was synthesized from 4-bromo-1,8- naphthalimide and trimethylsilyl- acetylene. The absorption and fluorescence spectra of 4-benzofuranyl-1,8- naphthalimides were studied and the quantum yields were measured. The maximum UV/vis absorption spectra were in the range of 375-400 nm and the maximum emission spectra were in the range of 470-510 nm. The electro- luminescent properties were also mensurated through a doped electroluminescent device which contains 1% 1,8-naphthalimides and 99% CBP (4,4'-N,N'-dicarbazole-biphenyl), It’s shown the maximum brightness reached 3700 cd/ m2 at 22.5V.


2019 ◽  
Vol 16 (3(Suppl.)) ◽  
pp. 0764 ◽  
Author(s):  
Al-Hamdani Et al.

            The research is dealing with the absorption and fluorescence spectra for the hybrid of  an Epoxy Resin doped with organic dye Rhodamine (R6G) of different concentrations (5*10-6, 5*10-5, 1*10-5, 1*10-4, 5*10-4) Mol/ℓ at room temperature. The Quantum efficiency Qfm, the rate of fluorescence emission Kfm (s-1), the non-radiative lifetime τfm (s), fluorescence lifetime τf and the Stokes shift were calculated. Also the energy gap (Eg) for each dye concentration was evaluated. The results showed that the maximum quantum efficiency 62 % and maximum stokes shift 96 nm was obtained in dye concentration 5*10-6 and 1*10-4. The energy gap ranges between 1.066 eV to 1.128 eV depending proportionally on the dye concentrations.


1990 ◽  
Vol 45 (5) ◽  
pp. 618-622 ◽  
Author(s):  
A. Bączyński ◽  
P. Targowski ◽  
B. Ziętek ◽  
D. Radomska

Abstract Analytical expressions of absorption and fluorescence spectra of some coumarins in ethyl alcohol at room temperature are given. Satisfactory agreement of measured and calculated spectra is obtained. It was possible to obtain the pure electronic transition energies immediately after excitation (from absorption spectra) and after the thermal and orientational equilibrium is reached (from fluorescence). An optical transition carries a dye-solvent system to a state in which the mutual interaction energy is larger than in the initial state


Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 138
Author(s):  
Zhijiang Che ◽  
Jian Zhang ◽  
Baiyi Wu ◽  
Qiangqiang Hu ◽  
Wenxiang Mu ◽  
...  

Single crystal fibers of 30% Er3+-doped compound of Y3(ScxGa1−x)5O12 have been grown by using the micro-pulling down (μ-PD) technique successfully. Our main purpose is to tune the fluorescence properties by adjusting the ratios of Sc3+ and Ga3+ ions inside the matrix crystals. The crystal structures of the series compounds were measured and analyzed through X-ray diffraction (XRD) measurements. The components and doping elements distributions were measured by the X-ray Fluorescence spectrometry and electron-probe microanalyzer. The absorption and mid-infrared fluorescence spectra, including the fluorescent lifetime of Er3+:4I13/2 and 4I11/2 levels were measured and compared systematically at room temperature. Spectral analysis indicated that the fluorescent lifetime of Er3+:4I13/2 tended to shorten and the emission spectra began to show a red shift when the proportion of YSG increased in the compound. Furthermore, the Raman spectra were measured to reveal the variations of lattice vibration and phonon energy.


2015 ◽  
Vol 1089 ◽  
pp. 121-124
Author(s):  
Gao Zhang Gou ◽  
Bo Zhou ◽  
Ling Shi ◽  
Xian Lan Chen ◽  
Na Wu ◽  
...  

One Bis-Boc-L-alanine-1,8-naphthyridine ligand containing amino acid by amido bond named 2,7-Bis-Boc-L-alanine-1,8-naphthyridine (L1) was synthesized and characterized. And there absorption and fluorescence spectra in methanol is presented. It exhibits electronic absorption spectra with λmax at about 340 nm, which can be tentatively assigned to π→π* transition. The emission spectra of L1 in CH3OH shows a mirror symmetry peak with λmax at about 375 nm. Then, the comprehensive study of spectroscopic properties upon titration of L1 with heavy metal ions as ion source in CH3OH was investigated.


2013 ◽  
Vol 543 ◽  
pp. 373-376 ◽  
Author(s):  
Nurul Huda Yusoff ◽  
Muhamad Mat Salleh ◽  
Muhammad Yahaya

Room temperature fluorescence gas sensor was developed based on TiO2 nanoparticles coated with porphyrin dye thin films. The porphyrin dye used for this experiment were Iron (III) meso-tetraphenylporphine chloride (IMTPPCl) and Manganase (III) 5,10,15,20 tetra (4-pyridyl)-21H, 23H porphine chloride tetrakis (metachloride). The sensing sensitivity was due to the changes of the emission spectra produce by the thin film when expose to the organic vapors from volatile organic compounds; ethanol, acetone and 2-propanol. Both thin films show good response toward volatile organic vapors. However, TiO2 nanoparticles with porphyrin; IMTPPCl thin film shows pronounced interaction, marked fluorescence spectra and more selective property, hence useful for chemical identification purpose.


2021 ◽  
Vol 2063 (1) ◽  
pp. 012025
Author(s):  
Roza Al-Aqar

Abstract The compound of (4-hydroxy-3-nitro-1,8-naphthalic anhydride) and the dopant material (4-hydroxy-m-benzene-disulfonic acid) were synthesized. The UV-Vis absorption and fluorescence spectra of the compound were recorded. The bathochromic shifts in absorption due to the changes in the solvent polarity was observed, in DMSO solvent, the compound shows different peaks, three bands in the UV region and one band in the visible region, one absorption peak at 402 nm, which might be attributed to the (ICT) band. The emission spectra of this compound were sensitive to the solvent polarity. They moved to lower energies with increasing the polarity of the solvent. The influence of the solvent polarity on the fluorescence maximum was more pronounced compared with the absorption maximum, showing ca. 3 nm red shift on moving from butanol to DMSO. The effect of the dopant material on the conductivities (ionic and specific) of the compound was studied, the ionic conductivity was increased as the weight of the dopant material increases, and the ionic conductivity (G) was measured in water as a solvent. the (G) of the compound was 2.4X10-6 Siemens at 0.01 gm of the dopant material, and was 2.62X10-4 Siemens after the dopant material was added (0.1 gm).


2019 ◽  
Vol 12 (24) ◽  
pp. 1-9
Author(s):  
Asmaa N. Ahmed

been taken at room temperature down to liquid nitrogen temperature (77K). Polar and nonpolar solvents have been used to study the solvent effect on the absorption and fluorescence spectra of solute molecules. Some of the spectroscopic parameters have been determined as functions of solvent polarity and temperature. The results indicate that the band width FWHM increases with increasing the solvent polarity and temperature, while the peak emission cross section decreases with increasing of solvent polarity and decreases with increasing the temperatures. Clear vibrational structure spectra of benzoanthracene molecules have been observed in Nonane and Hexane solvents at 77K.


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