Multifunctional Thermally Activated Delayed Fluorescence Emitters and Insight into Multicolor‐Mechanochromism Promoted by Weak Intra‐ and Intermolecular Interactions

2019 ◽  
Vol 7 (22) ◽  
pp. 1900727 ◽  
Author(s):  
Kailu Zheng ◽  
Hannan Yang ◽  
Fan Ni ◽  
Zhanxiang Chen ◽  
Shaolong Gong ◽  
...  
Keyword(s):  
Intermolecular Interactions ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Insight Into

scholarly journals Intermolecular interactions in molecular crystals and their effect on thermally activated delayed fluorescence of helicene-based emitters

2018 ◽  
Vol 6 (39) ◽  
pp. 10557-10568 ◽  
Author(s):  
Anastasia Klimash ◽  
Piotr Pander ◽  
Wim T. Klooster ◽  
Simon J. Coles ◽  
Przemyslaw Data ◽  
...  
Keyword(s):  
Intermolecular Interactions ◽  
Molecular Crystals ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor

In crystals of donor–acceptor helicene molecules, thermally activated delayed fluorescence (TADF) is strongly enhanced by the presence of occluded hexane molecules.

scholarly journals Photoluminescence and Electrochemiluminescence of Thermally Activated Delayed Fluorescence (TADF) Emitters Containing Diphenylphosphine Chalcogenide-Substituted Carbazole Donors

2021 ◽  
Author(s):  
Shiv Kumar ◽  
Pauline Tourneur ◽  
Jonathan Adsetts ◽  
Michael Wong ◽  
Pachaiyappan Rajamalli ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Polar Media ◽  
Delay Times ◽  
Derivatives Of ◽  
Homo Lumo ◽  
Rising Time ◽  
Insight Into

Aiming to develop efficient blue-emitting thermally activated delayed fluorescence (TADF) compounds, we have designed and synthesized derivatives of the well-known sky-blue emitter 2CzPN that contain electron-accepting phosphine chalcogenide groups to stabilize the HOMO level relative to the pristine compound, thus increasing the HOMO-LUMO gap and blue-shifting the emission wavelength. By cyclic voltammetry, photophysical data and quantum-chemical calculations, it was found that polar solvents and matrices validated the proposed concept, but these trends were not recovered in non-polar media. The suitability of these 2CzPN derivatives in polar matrices for optoelectronic applications was explored with electrochemiluminescence (ECL) by measuring emission delays, radical stability, emission stabilities, emission efficiencies and emission spectra. Some of the 2CzPN derivatives showed an unprecedented delayed onset of the ECL, and delayed rising time to the ECL maximum, as well as long ECL emission decay. All of these mentioned delay times suggest that these luminophores primarily emit via organic long-persistent electrochemiluminescence (OLECL) mechanisms. The derivatization of the donor groups of the emitters affected both the radical stability and the predominant emission mechanism, providing important insight into their potential as emitters in solid-state electroluminescent devices.

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

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