Up-Conversion Intersystem Crossing Rates in Organic Emitters for Thermally Activated Delayed Fluorescence: Impact of the Nature of Singlet vs Triplet Excited States

2017 ◽  
Vol 139 (11) ◽  
pp. 4042-4051 ◽  
Author(s):  
Pralok K. Samanta ◽  
Dongwook Kim ◽  
Veaceslav Coropceanu ◽  
Jean-Luc Brédas
Keyword(s):  
Excited States ◽  
Delayed Fluorescence ◽  
Intersystem Crossing ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Triplet Excited States

scholarly journals Exploiting trifluoromethyl substituents for tuning orbital character of singlet and triplet states to increase the rate of thermally activated delayed fluorescence

2020 ◽  
Vol 4 (12) ◽  
pp. 3602-3615 ◽  
Author(s):  
Jonathan S. Ward ◽  
Andrew Danos ◽  
Patrycja Stachelek ◽  
Mark A. Fox ◽  
Andrei S. Batsanov ◽  
...  
Keyword(s):  
Excited States ◽  
Organic Molecules ◽  
Delayed Fluorescence ◽  
Triplet States ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Conjugated Organic Molecules ◽  
Singlet And Triplet States ◽  
Triplet Excited States ◽  
Orbital Character

This work shows that trifluoromethyl (CF3) substituents can be used to increase the rate of thermally activated delayed fluorescence (TADF) in conjugated organic molecules by tuning the excitonic character of the singlet and triplet excited states.

scholarly journals The Role of Local Triplet Excited States and D-A Relative Orientation in Thermally Activated Delayed Fluorescence: Photophysics and Devices

2016 ◽  
Vol 3 (12) ◽  
pp. 1600080 ◽  
Author(s):  
Fernando B. Dias ◽  
Jose Santos ◽  
David R. Graves ◽  
Przemyslaw Data ◽  
Roberto S. Nobuyasu ◽  
...  
Keyword(s):  
Excited States ◽  
Delayed Fluorescence ◽  
Relative Orientation ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Triplet Excited States

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>

All-organic fast intersystem crossing assisted exciplexes exhibiting sub-microsecond thermally activated delayed fluorescence

2021 ◽  
Author(s):  
Kaspars Traskovskis ◽  
Armands Sebris ◽  
Irina Novosjolova ◽  
Maris Turks ◽  
Matas Guzauskas ◽  
...  
Keyword(s):  
Delayed Fluorescence ◽  
Intersystem Crossing ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Novel Strategy

A novel strategy is presented towards acquisition of exciplex systems exhibiting thermally activated delayed fluorescence (TADF) with high reverse intersystem crossing (RISC) rate (exceeding 107 s-1). This approach involves constructing...

A quantitative description of photoluminescence efficiency of a carbazole-based thermally activated delayed fluorescence emitter

2019 ◽  
Vol 43 (15) ◽  
pp. 6032-6039
Author(s):  
Songyan Feng ◽  
Xugeng Guo ◽  
Jinglai Zhang
Keyword(s):  
Quantitative Description ◽  
Energy Difference ◽  
Delayed Fluorescence ◽  
Intersystem Crossing ◽  
Small Energy ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Fluorescence Efficiency ◽  
High Fluorescence ◽  
Photoluminescence Efficiency

The present results reveal that the dominant charge transfer characteristics in the S1 and T1 states produce a small energy difference between the two states, and consequently an efficient reverse intersystem crossing process and a high fluorescence efficiency.

Over 20% external quantum efficiency in red thermally activated delayed fluorescence organic light-emitting diodes using a reverse intersystem crossing activating host

2018 ◽  
Vol 6 (20) ◽  
pp. 5363-5368 ◽  
Author(s):  
Ji Han Kim ◽  
Dong Ryun Lee ◽  
Si Hyun Han ◽  
Jun Yeob Lee
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Intersystem Crossing ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light

Highly efficient red thermally activated delayed fluorescence organic light-emitting diodes were developed using a reverse intersystem crossing activating host derived from phenylcarbazole and pyridofuropyridine.

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