Quantum yields of [W(CN)8]4? formation in charge-transfer photochemistry of octacyanotungstate (V)

1982 ◽  
Vol 7 (3) ◽  
pp. 131-134 ◽  
Author(s):  
Barbara Sieklucka ◽  
Aleksandra Kanas ◽  
Alina Samotus
Keyword(s):  
Charge Transfer ◽  
Quantum Yields

A general strategy via charge transfer sensitization to achieve efficient NIR luminescence in lanthanide-doped NaGdS2 nanocrystals

2021 ◽  
Vol 9 (15) ◽  
pp. 5148-5153
Author(s):  
Shiteng Wang ◽  
Chunguang Zhang ◽  
Wei Zheng ◽  
Zhongliang Gong ◽  
Ping Huang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Quantum Yields ◽  
General Strategy ◽  
Nir Luminescence ◽  
Co Doped

A strategy based on S2−-to-Yb3+ charge transfer sensitization is developed to achieve efficient NIR luminescence in Yb3+ singly-doped and Yb3+/Er3+ co-doped NaGdS2 nanocrystals with quantum yields up to 21.2% and 25.0%, respectively.

scholarly journals Solution-Processed OLEDs Based on Thermally Activated Delayed Fluorescence Copper(I) Complexes with Intraligand Charge-Transfer Excited State

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1125
Author(s):  
Teng Teng ◽  
Jinfan Xiong ◽  
Gang Cheng ◽  
Changjiang Zhou ◽  
Xialei Lv ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Functional Theory ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Wide Range

A new series of tetrahedral heteroleptic copper(I) complexes exhibiting efficient thermally-activated delayed fluorescence (TADF) in green to orange electromagnetic spectral regions has been developed by using D-A type N^N ligand and P^P ligands. Their structures, electrochemical, photophysical, and electroluminescence properties have been characterized. The complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 0.71 at room temperature in doped film and the lifetimes are in a wide range of 4.3–24.1 μs. Density functional theory (DFT) calculations on the complexes reveal the lowest-lying intraligand charge-transfer excited states that are localized on the N^N ligands. Solution-processed organic light emitting diodes (OLEDs) based on one of the new emitters show a maximum external quantum efficiency (EQE) of 7.96%.

scholarly journals Tetraphenylethenyl-Modified 1,8-Naphthalimide Dye with Efficient Aggregation-Enhanced Emisssion, Solvatochromism and Intramolecular Charge Transfer Characteristics

2021 ◽  
Vol 2109 (1) ◽  
pp. 012025
Author(s):  
Qiuli Zhao ◽  
Qinghao Yang
Keyword(s):  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Quantum Yields ◽  
Transfer Property ◽  
Organic Luminophores ◽  
Emission Color ◽  
High Fluorescence ◽  
Photo Stability ◽  
Chemical Fields ◽  
Naphthalimide Dye

Abstract 1,8-naphthalimide (NI) dyes are one class of important organic luminophores with good photo-stability, high fluorescent quantum yields and broad emission color-tunability, which are widely used in biological and chemical fields. However, they exhibit bad ACQ property, which heavily limits their application in real word. Contrary to ACQ, tetraphenylethene (TPE) is an AIE luminogen. To eliminate the ACQ effect of NI, TPE was used as core and NI chromophores was used as peripheries to obtain a new dye TPEDNI. TPEDNI dye demonstrates typical aggregation-enhanced emission (AEE) characteristic with high fluorescence Φ>F, solid up to 100% in the film state, which is 24 times of that for its THF solution. Besides, TPEDNI exhibits marked solvatochromism, and the emission peak red-shifts from 505 nm in hexane to 610 nm in acetonitrile. TPENI also displays evident intramolecular charge transfer property in THF/water mixtures

Influence of protonation of peripheral substituents on photophysical and photochemical properties of tetrapyrazinoporphyrazines

2010 ◽  
Vol 14 (07) ◽  
pp. 582-591 ◽  
Author(s):  
Veronika Novakova ◽  
Eva H. Mørkved ◽  
Miroslav Miletin ◽  
Petr Zimcik
Keyword(s):  
Charge Transfer ◽  
Sulfuric Acid ◽  
Singlet Oxygen ◽  
Electron Pair ◽  
Intramolecular Charge Transfer ◽  
Quantum Yields ◽  
Considerable Decrease ◽  
Fluorescence Quantum Yields ◽  
Photochemical Properties ◽  
Free Electron Pair

Octasubstituted zinc tetrapyrazinoporphyrazines with four N,N-dimethylaminophenyls and four phenyl or pyridin-3-yl substituents were synthesized and fully characterized. Their fluorescence quantum yields in DMF or pyridine were very low, almost undetectable, as a consequence of ultrafast intramolecular charge transfer. Titration of their DMF solutions with sulfuric acid led to increase of the fluorescence quantum yields by two orders of magnitude when the full protonation of peripheral substituents was achieved. Intramolecular charge transfer is no longer a favorable way of excited-state relaxation at full protonation of N,N-dimethylaminophenyl substituents because of loss of donor centers (free electron pair on its nitrogen). Similarly, singlet oxygen quantum yields also increased by two orders of magnitude when sulfuric acid was added to tetrapyrazinoporphyrazine solutions in DMF. Protonation at azomethine nitrogens of tetrapyrazinoporphyrazine macrocycle was observed at higher acid concentrations and it led to considerable decrease of fluorescence quantum yields. Octaphenyl zinc tetrapyrazinoporphyrazine and octa(pyridin-3-yl) zinc tetrapyrazinoporphyrazine were used as controls without intramolecular charge transfer. Their fluorescence and singlet oxygen quantum yields were high in DMF and decreased at higher concentrations of sulfuric acid due to protonation of azomethine nitrogens. The results suggest that the photophysical and photochemical properties of studied compounds may be controlled by changes of pH of medium.

A red thermally activated delayed fluorescence emitter employing dipyridophenazine with a gradient multi-inductive effect to improve radiation efficiency

2019 ◽  
Vol 7 (25) ◽  
pp. 7525-7530 ◽  
Author(s):  
Huiqin Wang ◽  
Bingjie Zhao ◽  
Peng Ma ◽  
Zhe Li ◽  
Xinyu Wang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Inductive Effect ◽  
Intramolecular Charge Transfer ◽  
Radiative Transition ◽  
Delayed Fluorescence ◽  
Radiation Efficiency ◽  
Quantum Yields ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Electro Luminescence

Red TADF emitter oTPA-DPPZ employs dipyridophenazine with gradient multi-inductive effect as acceptor, which enhances intramolecular charge transfer and radiative transition, resulting photo- and electro-luminescence quantum yields of 75% and 18.5%.

Photodisproportionation of (1,5-Cyclooctadiene) copper(I) Hexafluoroacetylacetonate Induced by Metal-to-Ligand Charge Transfer Excitation

2003 ◽  
Vol 58 (7) ◽  
pp. 704-707 ◽  
Author(s):  
Horst Kunkely ◽  
Arnd Vogler
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Quantum Yields ◽  
Long Wavelength ◽  
Ligand Charge Transfer ◽  
Elemental Copper ◽  
Charge Transfer Excitation ◽  
Reactive Excited State

The complex CuI(COD)(hfac) with COD = 1,5- cyclooctadiene and hfac = hexafluoroacetyl-acetonate shows two long-wavelength absorptions at λmax = 308 and 241 nm which are assigned to hfac intraligand (IL) and CuI →COD metal-to-ligand charge transfer (MLCT) transitions, respectively. The photolysis of CuI(COD)(hfac) in hexane leads to the release of the olefin and the subsequent disproportionation of CuI(hfac) to elemental copper and CuII(hfac)2 with the quantum yields Φ = 10−3 at λirr =313 nm and Φ = 3×10−3 at λirr = 254 nm. It is suggested that the reactive excited state is of the MLCT type.

Fluorescence of Trans-4-Cyano-4′-dimethylaminostilbene; No Evidence for a TICT State

1983 ◽  
Vol 38 (8) ◽  
pp. 928-936 ◽  
Author(s):  
Henry Gruen ◽  
Helmut Görner
Keyword(s):  
Charge Transfer ◽  
Double Bond ◽  
Relaxation Process ◽  
Singlet State ◽  
Intramolecular Charge Transfer ◽  
Solvent Polarity ◽  
Quantum Yields ◽  
Excited Singlet ◽  
Dual Emission ◽  
Fluorescence Maximum

AbstractThe fluorescence properties of trans-4-cyano-4′-dimethylaminostilbene (trans-1) and a rigid analogue, in which the dimethylaminophenyl group is replaced by an indoline ring, trans-l-(4-cyanophenyl)-2-(5-[2,3-dihydro]N-methylindolyl)ethylene (trans-2) were studied in 20 solvents. The quantum yields of fluorescence (Φf) and of trans→cis photoisomerization (Φt→c) as well as the fluorescence maximum (ν̃f) and the bandwidth (⊿ν̃f) were examined. The activation energies (range: 3.5-7.8 kcal/mol) obtained from <2>f and <£t_c measurements are nearly the same for 1 and 2 in a given solvent. Φf , ν̃f and ⊿ν̃f as a function of solvent polarity and temperature show similar trends for 1 and 2. No dual emission was observed for either of the cyanostilbenes. These findings indicate that a twisted intramolecular charge transfer (TICT) state is not involved in the relaxation process of the first excited trans singlet state (1t*). The main deactivation pathway of 1t* competing with fluorescence is trans→cis photoisomerization by twisting about the C = C double bond in the first excited singlet state for both.

Are Very Small Emission Quantum Yields Characteristic of Pure Metal-to-Ligand Charge-Transfer Excited States of Ruthenium(II)-(Acceptor Ligand) Chromophores?

2016 ◽  
Vol 55 (15) ◽  
pp. 7341-7355 ◽  
Author(s):  
Chia Nung Tsai ◽  
Shivnath Mazumder ◽  
Xiu Zhu Zhang ◽  
H. Bernhard Schlegel ◽  
Yuan Jang Chen ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Pure Metal ◽  
Quantum Yields ◽  
Ligand Charge Transfer

Ultrafast intramolecular charge transfer in tetrapyrazinoporphyrazines controls the quantum yields of fluorescence and singlet oxygen

2010 ◽  
Vol 12 (11) ◽  
pp. 2555 ◽  
Author(s):  
Veronika Novakova ◽  
Petr Zimcik ◽  
Miroslav Miletin ◽  
Lenka Vachova ◽  
Kamil Kopecky ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Singlet Oxygen ◽  
Intramolecular Charge Transfer ◽  
Quantum Yields

scholarly journals Synthesis and Photophysical Properties of a Series of Dimeric Indium Quinolinates

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 34
Author(s):  
Sang Woo Kwak ◽  
Ju Hyun Hong ◽  
Sang Hoon Lee ◽  
Min Kim ◽  
Yongseog Chung ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Nmr Spectroscopy ◽  
1H Nmr Spectroscopy ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Solvent Polarity ◽  
Low Energy ◽  
Quantum Yields ◽  
Absorption Bands ◽  
Indium Complexes

A novel class of quinolinol-based dimeric indium complexes (1–6) was synthesized and characterized using 1H and 13C(1H) NMR spectroscopy and elemental analysis. Compounds 1–6 exhibited typical low-energy absorption bands assignable to quinolinol-centered π–π* charge transfer (CT) transition. The emission spectra of 1–6 exhibited slight bathochromic shifts with increasing solvent polarity (p-xylene < tetrahydrofuran (THF) < dichloromethane (DCM)). The emission bands also showed a gradual redshift, with an increase in the electron-donating effect of substituents at the C5 position of the quinoline groups. The absolute emission quantum yields (ΦPL) of compounds 1 (11.2% in THF and 17.2% in film) and 4 (17.8% in THF and 36.2% in film) with methyl substituents at the C5 position of the quinoline moieties were higher than those of the indium complexes with other substituents.

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