scholarly journals Selective Synthesis and Photoluminescence Study of Pyrazolopyridopyridazine Diones and N-Aminopyrazolopyrrolopyridine Diones

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2409
Author(s):  
Ching-Chun Tseng ◽  
Cheng-Yen Chung ◽  
Shuo-En Tsai ◽  
Hiroyuki Takayama ◽  
Naoto Uramaru ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Intensity ◽  
Substituent Effect ◽  
Emission Spectra ◽  
Selective Synthesis ◽  
Hydrazine Monohydrate ◽  
Photoluminescence Study ◽  
Chloro Group

The newly designed luminol structures of pyrazolopyridopyridazine diones and N-aminopyrazolopyrrolopyridine diones were synthesized from versatile 1,3-diaryfuropyrazolopyridine-6,8-diones, 1,3-diarylpyrazolopyrrolopyridine-6,8-diones, or 1,3-diaryl-7-methylpyrazolopyrrolopyridine-6,8-diones with hydrazine monohydrate. Photoluminescent and solvatofluorism properties containing UV–Vis absorption, emission spectra, and quantum yield (Φf) study of pyrazolopyridopyridazine diones and N-aminopyrazolopyrrolopyridine diones were also studied. Generally, most of pyrazolopyrrolopyridine-6,8-diones 6 exhibited the significant fluorescence intensity and the substituent effect when compared with N-aminopyrazolopyrrolopyridine diones, particularly for 6c and 6j with a m-chloro group. Additionally, the fluorescence intensity of 6j was significantly promoted due to the suitable conjugation conformation. Based on the quantum yield (Φf) study, the value of compound 6j (0.140) with planar structural skeletal was similar to that of standard luminol (1, 0.175).

scholarly journals Synthesis and characterization of CdSxSe1−xalloy quantum dots with composition-dependent band gaps and paramagnetic properties

RSC Advances ◽  
2018 ◽  
Vol 8 (52) ◽  
pp. 30002-30011 ◽  
Author(s):  
Yueh-Chi Chung ◽  
Chien-Hsin Yang ◽  
Hao-Wen Zheng ◽  
Ping-Szu Tsai ◽  
Tzong-Liu Wang
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Fluorescence Intensity ◽  
Band Gaps ◽  
Synthesis And Characterization ◽  
Paramagnetic Properties

Both the fluorescence intensity and quantum yield of all the nanocrystals are much enhanced after the CdSxSe1−xQD cores are coated with a ZnS shell.

Enhancement of Fluorescence in Colloidal CuInS2 Nanocrystals by Introduction of Crystal Defect

2009 ◽  
Vol 1176 ◽  
Author(s):  
Masato Uehara ◽  
Kosuke Watanabe ◽  
Yasuyuki Tajiri ◽  
Hiroyuki Nakamura ◽  
Hideaki Maeda
Keyword(s):  
Phase Separation ◽  
Quantum Yield ◽  
Metal Complexes ◽  
Fluorescence Intensity ◽  
Fluorescence Quantum Yield ◽  
Bulk Material ◽  
Crystal Defects ◽  
Crystal Defect ◽  
Cu Deficiency ◽  
Cuins2 Nanocrystals

AbstractCu-In-S nanocrystals were developed as a low toxic fluorescent. The stoichiometric CuInS2 nanocrystals were synthesized facilely by heating a solution of metal complexes. The fluorescence would be originated from the crystal defect. We intentionally introduced the crystal defects related to Cu deficiency in nanocrystal with the prospect that the fluorescence intensity would be increased. The nanocrystals have many defects without phase separation as observed in bulk material. Consequently, the fluorescence quantum yield achieved to c.a. 6%. Moreover, the fluorescence quantum yield was increased up to 15% by the ZnS-coating.

Manifestation of Сoncentration Quenching of Fluoroaluminate Glasses Doped with Erbium

2019 ◽  
Vol 822 ◽  
pp. 871-877
Author(s):  
Victor Klinkov ◽  
Aleksander Semencha ◽  
Evgenia Tsimerman ◽  
Artem Osipov ◽  
Margarita G. Dronova
Keyword(s):  
Quantum Yield ◽  
Decay Curve ◽  
Emission Spectra ◽  
Luminescence Spectra ◽  
Ion Energy ◽  
Maximum Value ◽  
Absolute Quantum Yield ◽  
Concentration Dependences ◽  
Yield Values ◽  
Absolute Quantum

Fluoroaluminate glasses of the composition 2Ва (РО3)2–98MgCaSrBaYAl2F14-xErF3, where x=0, 0.1, 0.5, 1.0 mol. % have been prepared by melt quenching technique and characterized by optical absorption, emission spectra and decay curve analysis. Measured transmission spectra indicate the high practical relevance of the composition of glasses under investigation for photonics and optoelectronics products. In the region of 500–700 nm, luminescence spectra with peaks at about 522, 550, and 665 nm were obtained. The positions of the luminescence bands have been described using an erbium ion energy scheme. The concentration dependences of the absolute quantum yield values for the series of Er3+-doped fluoroaluminate glasses were also established. The maximum value of absolute quantum yield was found for a sample with Er3+ concentration 0.21∙1020 сm-3. The main reason for reducing the values of absolute quantum yield is concentration quenching.

Investigation of a novel triazatetrabenzcorrole photosensitizer

2002 ◽  
Vol 06 (07) ◽  
pp. 484-488 ◽  
Author(s):  
Zhenglin Song ◽  
Fushi Zhang ◽  
Xue Li ◽  
Shek-Kiu Chan ◽  
Fuqun Zhao ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Photodynamic Therapy ◽  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Emission Spectra ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Sulfo Groups

A novel phthalocyanine-like photosensitizer, oxophosphorus(V) tetrasulfotriaza-tetrabenzcorrole ( POTBCS 4), has been synthesized. Its structure and absorption spectrum are unique. POTBCS 4 has an axial P = O group and peripheral sulfo groups. The fluorescence emission spectra, fluorescence quantum yield and quantum yield of singlet oxygen generation have been studied. The uptake and the photodynamic activities against HeLa cells were measured. The results indicated that POTBCS 4 was a potential photosensitizer for photodynamic therapy (PDT).

scholarly journals Luminescent Tetranuclear Gold(I) Dibenzo[g,p]chrysene Derivatives: Effect of the Environment on Photophysical Properties

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 949 ◽  
Author(s):  
Francisco J. Caparrós ◽  
Mani Outis ◽  
Yongsik Jung ◽  
Hyeonho Choi ◽  
João Carlos Lima ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Quantum Yield ◽  
31P Nmr ◽  
High Resolution Mass Spectrometry ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Intermolecular Contacts ◽  
Supramolecular Aggregation ◽  
Resolution Mass

A new 2,7,10,15-tetraethynyldibenzo[g,p]chrysene ligand (1) and two tetranuclear gold(I) derivatives containing PPh3 (3) and PMe3 (4) phosphines were synthesized and characterized by 1H and 31P NMR, IR spectroscopy, and high-resolution mass spectrometry. The compounds were studied in order to analyze the effect of the introduction of gold(I) on the supramolecular aggregation and photophysical properties. Absorption and emission spectra displayed broad bands due to the establishment of π π interactions as an indication of intermolecular contacts and the formation of aggregates. A decrease of the recorded quantum yield (QY) of the gold(I) derivatives was observed compared to the uncomplexed ligand. The introduction of the complexes into poly methyl methacrylate (PMMA) and Zeonex 480R matrixes was analyzed, and an increase of the measured QY of 4 in Zeonex was observed. No phosphorescent emission was detected.

scholarly journals Demonstration of catecholamine and resorcinolamine derivatives as formaldehyde-induced fluorescence in protein models.

1988 ◽  
Vol 36 (6) ◽  
pp. 615-620
Author(s):  
L J Bryan ◽  
S R O'Donnell
Keyword(s):  
Fluorescence Intensity ◽  
Alkyl Chain ◽  
Emission Spectra ◽  
Ring Structure ◽  
Histochemical Demonstration ◽  
Wide Range ◽  
Protein Models ◽  
Fluorescence Microphotometry ◽  
Potential Use ◽  
Long Alkyl Chain

We assessed in protein droplet models the potential use of the formaldehyde condensation method for histochemical demonstration of a wide range of catecholamines and resorcinolamines. The experiments showed that all of the amines tested, except salbutamol and carbuterol, formed fluorophores, and that the fluorescence was specific [i.e., there was no fluorescence in the absence of formaldehyde, the fluorescence was quenched by water, and the fluorophores were subject to photodecomposition by the exciting (405-nm) light]. Peak wavelengths of the emission spectra were 480-485 nm for fluorophores of resorcinolamine derivatives. The fluorescence intensity of the catecholamines was greater than that of the resorcinolamines. Fluorophore formation was not hindered by substitution of t-butyl, phenylisoprophyl, or p-hydroxyphenylisopropyl on the amino-N in catecholamines (t-butylnorepinephrine, Cc24, Cc25, respectively) or resorcinolamines (terbutaline, Th1161, fenoterol, respectively), and fluorophores also formed for catecholamines with the amino-N in a ring structure (rimiterol) or with a long alkyl chain substituted on the amino-N (hexoprenaline). Our study showed that fluorescence microphotometry can be used to detect a range of drugs that are catecholamines or resorcinolamines, and hence it should be possible to use this technique to study the properties of dissipation of these amines in tissues.

scholarly journals Спектры люминесценции мощных светодиодов на основе нитрида галлия в ультрафиолетовой и фиолетовой областях спектра

2018 ◽  
Vol 52 (10) ◽  
pp. 1172
Author(s):  
В.В. Волков ◽  
Л.М. Коган ◽  
А.Н. Туркин ◽  
А.Э. Юнович
Keyword(s):  
Quantum Yield ◽  
Density Of States ◽  
Emission Spectra ◽  
Two Dimensional ◽  
Emission Power ◽  
Light Emitting ◽  
Potential Fluctuations ◽  
Long Wavelength ◽  
External Quantum Yield ◽  
A Current

AbstractThe electroluminescence spectra of high-power light-emitting diodes (LEDs) based on p – n heterostructures of the InGaN/AlGaN/GaN type emitting in the visible short-wavelength and ultraviolet spectral regions (the range from 370 to 460 nm) are investigated. The shape of spectra is described by a model taking into account a two-dimensional combined density of states and potential fluctuations. Additional long-wavelength peaks are found in emission spectra. The emission power of ultraviolet and violet LEDs reaches 233 mW at a current of 350 mA, and the external quantum yield reaches 23% at the maximum (near a current of 100 mA).

Luminescence from Photosystem I at High Temperatures

1980 ◽  
Vol 35 (3-4) ◽  
pp. 289-292 ◽  
Author(s):  
P. V. Sane ◽  
T. S. Desai ◽  
V. G. Tatake
Keyword(s):  
High Temperatures ◽  
Photosystem I ◽  
Fluorescence Intensity ◽  
Emission Spectra ◽  
Delayed Fluorescence ◽  
Fluorescence Maximum ◽  
Different Temperatures ◽  
Spinach Leaf

Abstract The changes in the fluorescence and delayed fluorescence intensity of spinach leaf as affected by temperature were studied. It was observed that the delayed fluorescence showed a maximum at about 45 °C whereas the fluorescence maximum was at about 55 °C. An examination of the emission spectra of delayed fluorescence at different temperatures showed that at higher temperatures the relative emission at 735 nm was increased. It is argued that at higher temperatures the luminescence from photosystem I contributes to delayed fluorescence.

Highly reliable all-fiber temperature sensor based on the fluorescence intensity ratio (FIR) technique in Er3+/Yb3+ co-doped NaYF4 phosphors

2019 ◽  
Vol 7 (48) ◽  
pp. 15269-15275 ◽  
Author(s):  
Hui Zhang ◽  
Jiatao Ye ◽  
Xiuli Wang ◽  
Shilong Zhao ◽  
Ruoshan Lei ◽  
...  
Keyword(s):  
Fluorescence Intensity ◽  
Temperature Sensor ◽  
Intensity Ratio ◽  
Emission Spectra ◽  
Fluorescence Intensity Ratio ◽  
Feasible Method ◽  
Temperature Probe ◽  
Fir Technique ◽  
Co Doped

A simple and feasible method was used to fabricate the optical temperature probe. A point all-fiber temperature sensor was built based on the up-conversion emission spectra of Er3+/Yb3+ co-doped NaYF4 phosphors.

scholarly journals Polyol-Mediated Synthesis of Nitrogen-Containing Carbon-Dots from Tetracyanobenzene with Intense Red Fluorescence

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1470 ◽  
Author(s):  
Roman Lehmacher ◽  
Claus Feldmann
Keyword(s):  
Polyethylene Glycol ◽  
Liquid Phase ◽  
Quantum Yield ◽  
Carbon Dots ◽  
Emission Spectra ◽  
Excitation Wavelength ◽  
Polyethylene Glycol 400 ◽  
Strong Emission ◽  
Red Emission ◽  
Naked Eye

Nitrogen-containing C-dots were prepared by heating (160 °C, 1 h) 1,2,4,5-tetracyanobenzene (TCB) in polyethylene glycol 400 (PEG400). The as-prepared monocrystalline C-dots were 2–4 nm in diameter and contained 24.4 wt. % of nitrogen. They showed intense fluorescence under excitation at 400–500 nm as well as under excitation at 600–700 nm. In addition to an excitation-wavelength-depending emission at 400 to 650 nm, the emission spectra exhibited a strong emission peaking at 715 nm, whose position was independent from the wavelength of excitation. For this deep-red emission a remarkable quantum yield of 69% was detected. The synthesis of nitrogen-containing C-dotswas completely performed in the liquid phase. Moreover, the C-dots could be directly dispersed in water. The resulting aqueous suspensions of PEG400-stabilized nitrogen-containing C-dots also showed intense red emission that was visible to the naked eye.

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