Design strategies for materials showing thermally activated delayed fluorescence and beyond: Towards the fourth-generation OLED mechanism

2018 ◽  
Vol 26 (4) ◽  
pp. 194-199 ◽  
Author(s):  
Hartmut Yersin ◽  
Larisa Mataranga-Popa ◽  
Shu-Wei Li ◽  
Rafal Czerwieniec
2021 ◽  
Author(s):  
Armands Ruduss ◽  
Baiba Turovska ◽  
Sergey Belyakov ◽  
Kitija Stucere ◽  
Aivars Vembris ◽  
...  

Through-space charge transfer (CT) process is observed in Cu(I) carbene-metal-amide complexes, where conventional imidazole or imidazoline N-heterocyclic (NHC) carbene fragments act as inert linkers and CT proceeds between a metal-bound carbazole donor and a distantly situated carbene-bound phenylsulfonyl acceptor. The resulting electron transfer gives a rise to efficient thermally activated delayed fluorescence (TADF), characterized with high photoluminescence quantum yields (ΦPL up to 90 %) and radiative rates (kr) up to 3.32×105 s-1. TADF process is aided by fast reverse intersystem crossing (rISC) rates of up to 2.56×107 s-1. Such emitters can be considered as hybrids of two existing TADF emitter design strategies, combining low singlet-triplet energy gaps (ΔEST) met in all-organic exciplex-like emitters (0.0062−0.0075 eV) and small, but non-negligible spin-orbital coupling (SOC) provided by Cu atom, like in TADF-active organometallic complexes.


2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda

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>


2021 ◽  
Vol 12 (11) ◽  
pp. 1692-1699
Author(s):  
Ji Hye Lee ◽  
Jinhyo Hwang ◽  
Chai Won Kim ◽  
Amit Kumar Harit ◽  
Han Young Woo ◽  
...  

New polystyrene-based polymers with high π-extended hole transport pendants were synthesized to obtain a low turn-on voltage and high efficiency in solution-processed green TADF-OLEDs.


2021 ◽  
Author(s):  
Cathay Chai Au-Yeung ◽  
Lok-Kwan Li ◽  
Man-Chung Tang ◽  
Shiu-Lun Lai ◽  
Wai-Lung Cheung ◽  
...  

We report the design of a new class of fused heterocyclic alkynyl ligand-containing gold(iii) complexes, which shows tunable emission colors spanning yellow to red region and exhibits thermally activated delayed fluorescence (TADF) properties.


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