Effect of fast thermal annealing on the optical spectroscopy in MBE- and CBE-grown GaInNAs/GaAs QWs: blue shift versus red shift

2004 ◽  
Vol 151 (5) ◽  
pp. 284-289 ◽  
Author(s):  
N. Balkan ◽  
A. Erol ◽  
R.J. Potter ◽  
S. Mazzucato ◽  
C.J. Hepburn ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Optical Spectroscopy ◽  
Blue Shift ◽  
Red Shift

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

1987 ◽  
Vol 65 (9) ◽  
pp. 2013-2018 ◽  
Author(s):  
R. Manoharan ◽  
Sneh K. Dogra
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Medium ◽  
Fluorescence Spectrum ◽  
Blue Shift ◽  
Proton Donor ◽  
Red Shift ◽  
The Other ◽  
Spectral Shifts ◽  
Other Hand

The red shift observed in the absorption spectrum of 2,7-diaminofluorene (DAF) in ether and acetonitrile is either due to the proton-donating capacity of the solute or due to its dispersive interactions with the solvent and a blue shift in methanol and water is due to the proton-accepting nature of DAF. DAF acts as a proton donor in S1 state in all solvents. The red shift in the fluorescence spectrum of the monocation of DAF relative to that of DAF is not because of the —NH2 group becoming more basic but because of the large solvent relaxating in aqueous medium. On the other hand, the monocation of DAF in cyclohexane follows the normal blue shift in the fluorescence spectrum. pKa values for the various prototropic reactions in S0 and S1 states are determined and discussed.

Effect of Thermal Annealing on the Photoluminescence Properties of a GaInNAs/GaAs Single Quantum Well

2000 ◽  
Vol 639 ◽  
Author(s):  
Laurent Grenouillet ◽  
Catherine Bru-Chevallier ◽  
Gérard Guillot ◽  
Philippe Gilet ◽  
Philippe Ballet ◽  
...  
Keyword(s):  
Quantum Well ◽  
Thermal Annealing ◽  
Low Temperatures ◽  
Blue Shift ◽  
Emission Peak ◽  
Single Quantum ◽  
Photoluminescence Properties ◽  
Single Quantum Well ◽  
Peak Energy ◽  
Strong Blue Shift

ABSTRACTWe report on the effect of thermal annealing on the photoluminescence properties of a Ga0.65In0.35N0.02As0.98/GaAs single quantum well. Thermal annealing is shown to decrease the strong nitrogen-induced localization effects observed at low temperatures and to reduce the full width at half maximum of the emission peak. It also induces a strong blue shift of the emission peak energy, which is thought not to arise from an In-Ga interdiffusion alone, as it is much larger than in a nitrogen-free reference single quantum well.

scholarly journals Impact of Solvents, Magnesium Oxide and Aluminium Oxide Nanoparticles on the Photophysical Properties of Acridine Orange Dye

2021 ◽  
pp. 1-7
Author(s):  
Fairooz Kareem ◽  
Mahasin Al-Kadhemy ◽  
Asrar Saeed
Keyword(s):  
Acridine Orange ◽  
Magnesium Oxide ◽  
Fluorescence Spectra ◽  
Aluminium Oxide ◽  
Blue Shift ◽  
Red Shift ◽  
Oxide Nanoparticles ◽  
Absorption And Fluorescence Spectra ◽  
Aluminium Oxide Nanoparticles ◽  
Al2o3 Nps

Absorption and fluorescence spectroscopy techniques were applied to investigate the photophysical characteristics of acridine orange (AO) dye in solvents that included distilled water, dimethyl sulfoxide (DMSO), acetone and ethanol in various concentrations (1×10-4–1×10-6) M. All of the samples were served at room temperature. The relationships between various parameters describing the strength of optical transitions in atoms and molecules were reviewed. This study expresses various viewpoints by describing how concentration and solvent affect the dye's absorption and fluorescence spectra. The absorption spectra of AO exhibit a band at (490 nm), except for DMSO, which shifts more towards red by 5 nm. The fluorescence spectra show a blue shift in AO aqueous solution around 6 nm until (0.5×10-4) M, followed by a red shift at around 7 nm at (1×10-6) M. There is a blue shift in (1×10-5) M for DMSO at around 4 nm, then a 10 nm red shift in higher concentrations as well as a 9 nm red shift in acetone and 6 nm in ethanol. Adding magnesium oxide nanoparticles (MgO NPs) quenched AO in both absorption and fluorescence spectra, whereas maximum fluorescence and intensity increased when aluminium oxide nanoparticles (Al2O3 NPs) were added to the solution. KEYWORDS Laser dye, absorption spectrum, fluorescence spectrum, MgO NPs, Al2O3 NPs

Structural and optical properties of CdSe, CdTe and CdSeTe nanoparticles dispersed in SiO2 films

2003 ◽  
Vol 789 ◽  
Author(s):  
P. Babu Dayal ◽  
N. V. Rama Rao ◽  
B. R. Mehta ◽  
S. M. Shivaprasad ◽  
P. D. Paulson
Keyword(s):  
Surface Layer ◽  
Silicon Dioxide ◽  
Thermal Annealing ◽  
Blue Shift ◽  
Annealing Effect ◽  
Self Organization ◽  
Structural And Optical Properties ◽  
Annealing Conditions ◽  
Optical And Electronic Properties ◽  
Nanoparticle Core

ABSTRACTCdSexTe1-x nanoparticles (with different stoichiometry ratio x) dispersed in silicon dioxide films have been grown by magnetron sputtering technique followed by thermal annealing. Effect of thermal annealing conditions on the structural, compositional, optical and electronic properties of nanoparticles has been studied using GAXRD, XPS, TEM, and spectroscopic ellipsometry techniques. A structural transformation in the nanoparticle core mediated purely by surface layer effects in the case of CdTe and a spontaneous self-organization of nanoparticles into nanorods in the case of CdSe via fractal growth has been observed. Preliminary observations from the ellipsometry measurements carried out on some of these nanoparticle films shows a blue shift of absorption edge.

scholarly journals Interaction Mechanism between Antibiotics and Humic Acid by UV-Vis Spectrometry

2018 ◽  
Vol 15 (9) ◽  
pp. 1911 ◽  
Author(s):  
Xiaoyu Yuan ◽  
Shengke Yang ◽  
Jie Fang ◽  
Xueli Wang ◽  
Haizhen Ma ◽  
...  
Keyword(s):  
Humic Acid ◽  
Absorption Band ◽  
Interaction Mechanism ◽  
Blue Shift ◽  
Degree Of Polymerization ◽  
Ultraviolet Spectrum ◽  
Red Shift ◽  
Vis Spectroscopy ◽  
Nm Range ◽  
Peak Value

In this study, the interaction between the humus and two antibiotics was studied by UV-Vis spectroscopy to describe the interaction mechanism and the effects of different environmental factors on the mechanism. Results showed that humic acid (HA) containing more aromatic groups was easily associated with antibiotics. In the HA-OTC, with the increase of the concentration of OTC, there were obvious absorption peaks in the 230–260 nm and 330–360 nm range, and the absorption band of the HA ultraviolet spectrum underwent a slight blue shift and the absorption intensity increased, demonstrating that a new ground state complex was generated. In the HA-SD, with the increase of SD concentration, an aromatic structure absorption peak appeared in the 190–220 nm range, and the peak value increased and the absorption band underwent a red shift, and the aromatization of HA decreased, which enhanced the interaction between the antibiotics and HA. With the increase of pH, the absorption band of HA, HA-OTC and HA-SD ultraviolet spectrum suffered a blue shift, the degree of polymerization of HA molecules decreased, and the number of adsorption binding sites increased, which resulted in the interaction of HA with antibiotics being enhanced. The absorption band of HA, HA-OTC and HA-SD displayed a red shift with the increase of ionic strength, which indicated that the repulsion within HA particles was weakened, and the molecular polymerization was strengthened and therefore, the interaction between antibiotics and HA was inhibited. The UV characteristics of the HA, HA-OTC and HA-SD systems were insensitive to the temperature. This study lays the foundation for better studying the effect of humus on the distribution of antibiotic residues in the environment.

scholarly journals The Cruciality of Single Amino Acid Replacement for the Spectral Tuning of Biliverdin-Binding Cyanobacteriochromes

2020 ◽  
Vol 21 (17) ◽  
pp. 6278
Author(s):  
Keiji Fushimi ◽  
Hiroki Hoshino ◽  
Naeko Shinozaki-Narikawa ◽  
Yuto Kuwasaki ◽  
Keita Miyake ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Near Infrared ◽  
Structural Characteristics ◽  
Blue Shift ◽  
Amino Acid Replacement ◽  
Red Shift ◽  
Single Amino Acid ◽  
Structural Basis ◽  
Small Unit

Cyanobacteriochromes (CBCRs), which are known as linear tetrapyrrole-binding photoreceptors, to date can only be detected from cyanobacteria. They can perceive light only in a small unit, which is categorized into various lineages in correlation with their spectral and structural characteristics. Recently, we have succeeded in identifying specific molecules, which can incorporate mammalian intrinsic biliverdin (BV), from the expanded red/green (XRG) CBCR lineage and in converting BV-rejective molecules into BV-acceptable ones with the elucidation of the structural basis. Among the BV-acceptable molecules, AM1_1870g3_BV4 shows a spectral red-shift in comparison with other molecules, while NpF2164g5_BV4 does not show photoconversion but stably shows a near-infrared (NIR) fluorescence. In this study, we found that AM1_1870g3_BV4 had a specific Tyr residue near the d-ring of the chromophore, while others had a highly conserved Leu residue. The replacement of this Tyr residue with Leu in AM1_1870g3_BV4 resulted in a blue-shift of absorption peak. In contrast, reverse replacement in NpF2164g5_BV4 resulted in a red-shift of absorption and fluorescence peaks, which applies to fluorescence bio-imaging in mammalian cells. Notably, the same Tyr/Leu-dependent color-tuning is also observed for the CBCRs belonging to the other lineage, which indicates common molecular mechanisms.

Effects of Cu Dopant on Lattice and Optical Properties of ZnS Quantum Dots

2016 ◽  
Vol 16 (4) ◽  
pp. 3816-3820
Author(s):  
Lu Shuhua ◽  
Wang Aiji ◽  
Chen Tingfang ◽  
Wang Yinshu
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Quantum Dot ◽  
Blue Shift ◽  
Red Shift ◽  
Colloidal Nanocrystals ◽  
Long Tail ◽  
Low Concentrations ◽  
Cu Dopant ◽  
Cu Ions

Doped and undoped ZnS colloidal nanocrystals have drawn much attention due to their versatile applications in the fields of optoelectronics and biotechnology. In this paper, Cu doped ZnS quantum dots were synthesized via the simple thermolysis of ethylxanthate salts. The lattice and optical properties of the nanocrystals were then studied in detail. The quantum dot lattice contracted linearly between Cu concentrations of 0.2–2%, while it continued to contract more gradually as Cu concentrations were further increased from 4 to 6%, due in part to the Cu ions located on the surface of the ZnS lattice. Cu incorporation induces a long tail in absorption at long wavelengths. The PL spectrum shows a red shift at first, and then a blue shift with increases in Cu concentration. Cu doped at low concentrations (0.2–1%) enhanced the emission, while high Cu concentrations (2–6%) quenched emissions.

Synthesis and Photophysical Properties of Side-Chain Polyfluorenes

2017 ◽  
Vol 865 ◽  
pp. 60-63
Author(s):  
Ning Wang ◽  
Xiao Dan Hu
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Photophysical Properties ◽  
Gel Permeation Chromatography ◽  
Blue Shift ◽  
Red Shift ◽  
Side Chain ◽  
Gel Permeation

In this paper, we reported one vinylfluorene derivative 9,9-dihexyl-vinylfluorene and its corresponding polymers. The monomer and polymers were characterized by NMR, UV-Vis, PL and Gel Permeation Chromatography (GPC). Compared with the monomer, the polymers showed blue-shift in UV-Vis spectra but red-shift in PL spedtra. This kind of side-chain polyfluorenes could be candidates of blue OLED, organic solar cells, and so on.

Analysis of Localized Surface Plasmon Resonance in Ag/ITO/CdS/SiO2 Multilayered Nanostructured Composite

NANO ◽  
2015 ◽  
Vol 10 (08) ◽  
pp. 1550117
Author(s):  
Chao Liu ◽  
Jingwei Lv ◽  
Famei Wang ◽  
Qiang Liu ◽  
Haiwei Mu ◽  
...  
Keyword(s):  
Refractive Index ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Localized Surface Plasmon Resonance ◽  
Surrounding Medium ◽  
Blue Shift ◽  
Red Shift ◽  
Localized Surface Plasmon ◽  
Extinction Spectra

Multilayered nanoshells have attracted much attention due to their unique optical, electronic and magnetic properties. In this work, numerical calculation using discrete dipole approximation (DDA) is conducted to investigate the quad-layered metal nanoshell consisting of a particle with a dielectric silica (SiO2) core, inner cadium sulfide (CdS) shell, middle indium tin oxide (ITO) shell and outer metal silver (Ag) shell. The phenomenon is interpreted by plasmon hybridization theory and the Ag–ITO–CdS–SiO2 multilayered nanoshells are studied by extinction spectra of localized surface plasmon resonance. The variation in the spectrum peak with nanoparticle thickness and refractive index of the surrounding medium is derived. The electric field enhancement contour around the nanoparticles under illumination is analyzed at the plasmon resonance wavelength. The [Formula: see text], [Formula: see text], and [Formula: see text] modes red-shift with the refractive index of the surrounding medium and increase in the layer thickness causes either blue-shift or red-shift as shown by the extinction spectra. The mechanism of the red-shift or blue-shift is discussed. The [Formula: see text] mode blue-shifts and furthermore, the [Formula: see text] and [Formula: see text] modes of the Ag coated multilayered nanostructure are noticeable by comparing the extinction efficiency spectra of the Au–ITO–CdS–SiO2 and Ag–ITO–CdS–SiO2 multilayered nanoshells.

Chemical Effects in Ion Implantation Induced Quantum Well Intermixing

2000 ◽  
Vol 647 ◽  
Author(s):  
Todd W. Simpson ◽  
Paul G. Piva ◽  
Ian V. Mitchell
Keyword(s):  
Quantum Well ◽  
Ion Implantation ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Blue Shift ◽  
Quantum Well Intermixing ◽  
Chemical Effects ◽  
M 31 ◽  
Shift Data ◽  
Fluence Dependence

AbstractIon implantation followed by rapid thermal annealing is used to induce layer intermixing and thus selectively blue-shift the emission wavelength of InP-based quantum well hetero- structures. The intermixing is greatly enhanced over thermal intermixing due to the supersaturation of defects. The magnitude of the observed blue-shift has been studied previously as a function of ion fluence and ion mass: the dependence on ion mass is well established, with heavier ions producing a larger shift. We show here that chemical effects can also play a significant role in determining the induced blue-shift. Data are presented from the implantation of the similar mass ions; aluminum (m~27), silicon (m~28) and phosphorus (m~31). The P- induced blue shift displays a monotonic increase with fluence, consistent with previous studies; however, the fluence dependence of Al- and Si-induced blue-shifts both deviate significantly from the behaviour for P. These results have important implications for attempts to scale intermixing behaviour with ion mass.

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