Fluorescence, Phosphorescence, and Delayed Fluorescence of Benzil in Imidazolium Ionic Liquids

2012 ◽  
Vol 65 (9) ◽  
pp. 1291 ◽  
Author(s):  
Dinesh Chandra Khara ◽  
Anunay Samanta
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
Emission Spectra ◽  
Wavelength Dependence ◽  
Delayed Fluorescence ◽  
Excitation Wavelength ◽  
Imidazolium Ionic Liquids ◽  
Thermally Activated ◽  
Phosphorescence At Room Temperature ◽  
The Media

Temperature dependence of the emission behaviour of benzil has been studied in three imidazolium ionic liquids differing in their polarity and viscosity. Room temperature absorption and steady-state emission spectra suggest that the ground and excited state conformers of benzil in ionic liquids are similar to those in conventional organic solvents. The non-degassed solutions of benzil in ionic liquids show phosphorescence at room temperature in contrast to conventional solvents where phosphorescence is commonly observed in degassed conditions. This study reveals that a thermally activated reverse intersystem crossing (T1↝S1) process is responsible for the drastic change in phosphorescence intensity with temperature in ionic liquids. The rate constant () of this process is found to be dependent on the polarity of the media and is 5 times higher in most polar ionic liquids. The evidence of the presence of multiple conformers of benzil in frozen conditions is obtained from the excitation wavelength dependence of the phosphorescence spectra.

Tunable afterglow luminescence and triple-mode emissions of thermally activated carbon dots confined within nanoclays

2019 ◽  
Vol 7 (43) ◽  
pp. 13640-13646 ◽  
Author(s):  
Yuchen Deng ◽  
Peng Li ◽  
Haiyan Jiang ◽  
Xu Ji ◽  
Huanrong Li
Keyword(s):  
Activated Carbon ◽  
Carbon Dots ◽  
Room Temperature ◽  
Delayed Fluorescence ◽  
Excitation Wavelength ◽  
Room Temperature Phosphorescence ◽  
Temperature Variations ◽  
Thermally Activated ◽  
Multi Mode ◽  
Triple Mode

Tunable afterglow luminescence and interesting multi-mode emissions (fluorescence (FL), delayed fluorescence (DF), and room-temperature phosphorescence (RTP)) via excitation wavelength and temperature variations were achieved.

Degradation of imidazolium ionic liquids in a thermally activated persulfate system

2021 ◽  
Vol 412 ◽  
pp. 128624
Author(s):  
Tian-Lin Ren ◽  
Xi-Wen Ma ◽  
Xiao-Qiong Wu ◽  
Li Yuan ◽  
Yang-Li Lai ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Imidazolium Ionic Liquids ◽  
Thermally Activated ◽  
Activated Persulfate

Preparation and Properties of La2O3-CaO-P2O5 Glasses Doped with Eu3+ Ions

2016 ◽  
Vol 675-676 ◽  
pp. 376-379 ◽  
Author(s):  
Narun Luewarasirikul ◽  
Piyachat Meejitpaisan ◽  
Jakrapong Kaewkhao
Keyword(s):  
Calcium Phosphate ◽  
Molar Volume ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Emission Spectra ◽  
Phosphate Glasses ◽  
Excitation Wavelength ◽  
Melt Quenching ◽  
Volume Measurements ◽  
Doped Glasses

Lanthanum calcium phosphate glasses doped with Eu3+ ions in compositions 20La2O3:10CaO:(70-x)P2O5:xEu2O3 (where x = 0.05, 0.10, 0.50 and 1.50 mol%) were prepared by melt-quenching technique. The density and molar volume measurements were carried out at room temperature. The absorption spectra were investigated in the UV-Vis-NIR region from 200 to 2500 nm. The emission spectra of Eu3+-doped glasses centered at 590 nm (5D0→7F1), 612 nm (5D0→7F2), 652 nm (5D0→7F3) and 699 nm (5D0→7F4) have been observed with 393 nm excitation wavelength.

Ni-catalyzed cascade coupling reactions: synthesis and thermally-activated delayed fluorescence characterization of quinazolinone derivatives

2021 ◽  
Author(s):  
Zhongyan Chen ◽  
Lepeng Chen ◽  
Shou-Feng Zhang ◽  
Qianqian Zhen ◽  
Wenzhang Xiong ◽  
...  
Keyword(s):  
Functional Groups ◽  
Room Temperature ◽  
Delayed Fluorescence ◽  
Coupling Reactions ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Quinazolinone Derivatives

A nickel-catalyzed synthesis of 1,3-diaryl-6H-pyrazino[2,1-b]quinazolin-6-one was developed. This method enabled to access valuable pyrazino-fused quinazolinones with tolerance of many functional groups even at room temperature. The desired pyrazino-fused quinazolinones emit...

scholarly journals Regioisomeric Effect on the Excited-State Fate Leading to Room-Temperature Phosphorescence or Thermally Activated Delayed Fluorescence in a Dibenzophenazine-Cored Donor–Acceptor–Donor System

2021 ◽  
Author(s):  
Takumi Hosono ◽  
Nicolas Oliveira Decarli ◽  
Paola Zimmermann Crocomo ◽  
Tsuyoshi Goya ◽  
Leonardo Evaristo de Sousa ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Room Temperature Phosphorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
Emission Behavior

Exploring design principle for switching thermally activated dealyed fluorescecne (TADF) and room temperature phosphorescence (RTP) is a fundamentally imporant research in developing triplet-mediated photofunctional organic materials. Herein systematic studies on the regioisomeric and substituents effects in a twisted donor–acceptor–donor (D–A–D) scaffold (A = dibenzo[a,j]phenazine; D = dihydrophenazasiline) on the fate of the excited state have been performed. The study revealed that the regiosiomerism clearly affects the emission behavior of the D–A–D compounds. Distinct difference in TADF, dual TADF & RTP, and dual RTP were observed, depending on the host used. Furthermore, OLED organic light-emitting diodes (OLEDs) fabricated with the developed emitters achieved high external quantum yields for RTP-based OLEDS up to 7.4%.

scholarly journals Thermally activated delayed fluorescence vs. room temperature phosphorescence by conformation control of organic single molecules

2019 ◽  
Vol 7 (22) ◽  
pp. 6616-6621 ◽  
Author(s):  
Przemyslaw Data ◽  
Masato Okazaki ◽  
Satoshi Minakata ◽  
Youhei Takeda
Keyword(s):  
Room Temperature ◽  
Single Molecules ◽  
Delayed Fluorescence ◽  
Room Temperature Phosphorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Molecular Conformations ◽  
Thermally Activated ◽  
Luminescent Compound

The time-resolved photophysical analysis of a multi-color-changing mechanochromic luminescent compound has been disclosed, which reveals distinct different emission paths to boost TADF and RTP of the emitter depending on its molecular conformations.

scholarly journals Ionic Liquid Catalyzed Per-O-Acetylation and Benzylidene Ring-Opening Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 642 ◽  
Author(s):  
Mayur Thul ◽  
Yao-Peng Wu ◽  
Yi-Jyun Lin ◽  
Shu-Lin Du ◽  
Hsin-Ru Wu ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Ring Opening ◽  
Room Temperature ◽  
Catalytic Amount ◽  
Atom Economy ◽  
Selective Catalyst ◽  
Imidazolium Ionic Liquids ◽  
Ring Opening Reaction ◽  
Brönsted Acid

Tunable aryl imidazolium ionic liquids acting as Brønsted acid ionic liquids were found to be efficient catalysts for per-O-acetylation and reductive ring opening of benzylidene acetals. This method requires a truly catalytic amount of the least expensive available ionic liquids that are water-stable and reusable and also stable at room temperature. The reactions were obtained in one hour with good to excellent yields. These reactions can form C−O and C−H bonds with a high atom economy. Furthermore, the ionic liquid is an anomeric selective catalyst in per-O-acetylation and reductive ring opening of benzylidene acetals of sugar moieties.

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