An accurate measurement of the dipole orientation in various organic semiconductor films using photoluminescence exciton decay analysis

2019 ◽  
Vol 21 (13) ◽  
pp. 7083-7089 ◽  
Author(s):  
Ik Jang Ko ◽  
Hyuna Lee ◽  
Jin Hwan Park ◽  
Gyeong Woo Kim ◽  
Raju Lampande ◽  
...  
Keyword(s):  
Organic Semiconductor ◽  
Delayed Fluorescence ◽  
Semiconductor Films ◽  
Dipole Orientation ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Exciton Decay

In this study, we report an accurate and more reliable approach to estimate the dipole orientation of emitters especially phosphorescence, fluorescence and even thermally activated delayed fluorescence.

scholarly journals Acceptor plane expansion enhances horizontal orientation of thermally activated delayed fluorescence emitters

2020 ◽  
Vol 6 (41) ◽  
pp. eaba7855
Author(s):  
Yepeng Xiang ◽  
Pan Li ◽  
Shaolong Gong ◽  
Yu-Hsin Huang ◽  
Chun-Yu Wang ◽  
...  
Keyword(s):  
Power Efficiency ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Dipole Orientation ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Horizontal Orientation ◽  
Formidable Challenge ◽  
Influence Of Substituents

Manipulating orientation of organic emitters remains a formidable challenge in organic light-emitting diodes (OLEDs). Here, expansion of the acceptor plane of thermally activated delayed fluorescence (TADF) emitters was demonstrated to selectively modulate emitting dipole orientation. Two proof-of-the-concept molecules, PXZPyPM and PXZTAZPM, were prepared by introducing a planar 2-phenylpyridine or 2,4,6-triphenyl-1,3,5-triazine substituent into a prototypical molecule (PXZPM) bearing a pyrimidine core and two phenoxazine donors. This design approach suppressed the influence of substituents on electronic structures and associated optoelectronic properties. Accordingly, PXZPyPM and PXZTAZPM preserved almost the same excited states and similar emission characteristics as PXZPM. The expanded acceptor plane of PXZPyPM and PXZTAZPM resulted in a 15 to 18% increase in horizontal ratios of emitting dipole orientation. PXZPyPM supported its green device exhibiting an external quantum efficiency of 33.9% and a power efficiency of 118.9 lumen per watt, competitive with the most efficient green TADF OLEDs reported so far.

High-efficiency pure blue thermally activated delayed fluorescence emitters with a preferentially horizontal emitting dipole orientation via a spiro-linked double D–A molecular architecture

2019 ◽  
Vol 7 (35) ◽  
pp. 10851-10859 ◽  
Author(s):  
Xuan Zeng ◽  
Kuan-Chung Pan ◽  
Wei-Kai Lee ◽  
Shaolong Gong ◽  
Fan Ni ◽  
...  
Keyword(s):  
High Efficiency ◽  
Delayed Fluorescence ◽  
Molecular Architecture ◽  
Dipole Orientation ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated

A spiro-linked double D–A molecular architecture has been introduced to construct blue thermally activated delayed fluorescence (TADF) emitters with a preferentially horizontal emitting dipole orientation.

High-efficiency thermally activated delayed fluorescence emitters via a high horizontal dipole ratio and controlled dual emission

2020 ◽  
Vol 8 (24) ◽  
pp. 8012-8017
Author(s):  
Youngnam Lee ◽  
Jong-In Hong
Keyword(s):  
High Efficiency ◽  
Delayed Fluorescence ◽  
Dipole Orientation ◽  
Dual Emission ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated

OLED devices based on linear rod-like TADF emitters exhibited high device efficiencies of 29.9% and 25.8% by means of high horizontal emitting dipole orientation and controlled dual emission.

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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