High-Lying Triplet Excitons of Thermally Activated Delayed Fluorescence Molecules

2017 ◽  
Vol 121 (38) ◽  
pp. 20687-20695 ◽  
Author(s):  
Yoshifumi Noguchi ◽  
Osamu Sugino
Keyword(s):  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Triplet Excitons

Why Triage the Materials with Low Luminescence Quantum Efficiency: The Use of 35Cbz4BzCN as a Universal Host for Organic Light Emitting Diode through Effective Triplet Energy Transfer

2021 ◽  
Author(s):  
Yi-Mei Huang ◽  
Tse-Ying Chen ◽  
Deng-Gao Chen ◽  
Hsuan-Chi Liang ◽  
Cheng-Ham Wu ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Delayed Fluorescence ◽  
Triplet Energy ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Triplet Energy Transfer ◽  
Triplet Lifetime ◽  
Triplet Excitons

35Cbz4BzCN, a novel universal host with long triplet lifetime, has been developed. The triplet excitons in 35Cbz4BzCN can be effectively harvested by phosphorescence and thermally activated delayed fluorescence emitters. In...

Recent advances in organic thermally activated delayed fluorescence materials

2017 ◽  
Vol 46 (3) ◽  
pp. 915-1016 ◽  
Author(s):  
Zhiyong Yang ◽  
Zhu Mao ◽  
Zongliang Xie ◽  
Yi Zhang ◽  
Siwei Liu ◽  
...  
Keyword(s):  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Recent Advances ◽  
Triplet Excitons

Thermally activated delayed fluorescence: harvesting dark triplet excitons to generate bright emissive singlet excitons.

Thermally activated delayed fluorescence material with aggregation-induced emission properties for highly efficient organic light-emitting diodes

2018 ◽  
Vol 6 (11) ◽  
pp. 2873-2881 ◽  
Author(s):  
Yaodong Zhao ◽  
Weigao Wang ◽  
Chen Gui ◽  
Li Fang ◽  
Xinlei Zhang ◽  
...  
Keyword(s):  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Luminescent Materials ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Aggregation Induced Emission ◽  
Thermally Activated ◽  
Organic Light ◽  
Fluorescence Material ◽  
Triplet Excitons

Luminescent materials with aggregation-induced emission (AIE) properties exhibit high solid state emission, while thermally activated delayed fluorescence (TADF) materials can fully harvest singlet and triplet excitons to achieve efficient electroluminescence (EL).

scholarly journals Revisiting the Role of Charge Transfer and Local Excitations in Thermally Activated Delayed Fluorescence

2022 ◽  
Author(s):  
Leonardo Evaristo de Sousa ◽  
Piotr de Silva
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Delayed Fluorescence ◽  
Equilibrium Geometry ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Model Hamiltonian ◽  
The Difference ◽  
Triplet Excitons

Thermally activated delayed fluorescence (TADF) is a phenomenon that relies on the upconversion of triplet excitons to singlet excitons by means of reverse intersystem crossing (rISC). It has been shown both experimentally and theoretically that the TADF mechanism depends on the interplay between charge transfer and local excitations. However, the difference between the diabatic and adiabatic character of the involved excited states is rarely discussed in the literature. Here, we develop a diabatization procedure to implement a 4-state model Hamiltonian to a set of TADF molecules. We provide physical interpretation for the Hamiltonian elements and show their dependence on the electronic state of the equilibrium geometry. We also demonstrate how vibrations affect TADF efficiency by modifying the diabatic decomposition of the molecule. Finally, we provide a simple model that connects the diabatic Hamiltonian to the electronic properties relevant to TADF and show how such relationship translates into different optimization strategies for rISC, fluorescence and overall TADF performance.

peri-Acenoacene Molecules: Tuning of the Singlet and Triplet Excitation Energies by Modifying their Radical Character

2021 ◽  
Author(s):  
Alicia Omist ◽  
Gaetano Ricci ◽  
Amel Derradji ◽  
Ángel J. José Pérez-Jiménez ◽  
Emilio San Fabián ◽  
...  
Keyword(s):  
Light Emission ◽  
Energy Difference ◽  
Delayed Fluorescence ◽  
Excitation Energies ◽  
Thermally Activated Delayed Fluorescence ◽  
Triplet Excitation ◽  
Thermally Activated ◽  
Radical Character ◽  
Triplet Excitons

The energy difference between singlet and triplet excitons, or ΔEST, is a key magnitude for novel light-emission mechanisms (i.e., TADF or Thermally Activated Delayed Fluorescence) or other photoactivated processes. We...

scholarly journals Harvesting triplet excitons for near-infrared electroluminescence via thermally activated delayed fluorescence channel

iScience ◽  
2021 ◽  
Vol 24 (2) ◽  
pp. 102123
Author(s):  
You-Jun Yu ◽  
Xue-Qi Wang ◽  
Jing-Feng Liu ◽  
Zuo-Quan Jiang ◽  
Liang-Sheng Liao
Keyword(s):  
Near Infrared ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Triplet Excitons

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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