High efficiency in blue TADF OLED using favorable horizontal oriented host
Journal
Chemical Engineering Journal
Journal Volume
498
ISSN
1385-8947
Date Issued
2024-10
Author(s)
Yi-Zhen Li
Hsuan-Chi Liang
Chia-Hsun Chen
Ching-Huang Chiu
Lian-Chun Huang
Yi-Ting Lee
Yi-Chung Dzeng
Chi Chen
Bo-Yen Lin
Jiun-Haw Lee
Tien-Lung Chiu
Abstract
An appropriate host featuring a wide band gap (Eg) and high triplet energy (T1) is crucial for facilitating highly efficient blue-light emitting devices. In this study, 4Ac26CzBz, a new host comprising acridan and carbazole moieties linked to a benzimidazole core, has been synthesized and characterized. Notedly, 4Ac26CzBz exhibits a wide optical gap (Eg) and high triplet energy (T1) of 3.3 and 3.0 eV, respectively, and has been proven a suitable host for blue thermally activated delayed fluorescence (TADF) OLED. By adopting 4TCzBN as a blue-light dopant, a remarkably high device external quantum efficiency of 35.8 % (59.8 cd/A and 62.8 lm/W) and a low turn-on voltage (<3 eV) have been demonstrated, with significant suppression of the efficiency roll-off, maintaining a high efficiency of 29.7 % as luminance at 1000 cd/m2. This excellent performance is deduced from the host's ambipolar carrier transporting properties, which refer to its ability to transport both electrons and holes effectively, high photoluminescence quantum yield (PLQY) of 98.6 %, and highly horizontal orientation of transition dipole, as determined through diverse analytical measurements. The good material properties of 4Ac26CzBz and the high OLED performance reveal its potential for the next generation's advanced display and lighting applications.
Subjects
Acridan
Blue TADF OLED
Host materials
Low driving voltage
Publisher
Elsevier BV
Type
journal article