13.2% EQE near-infrared TADF OLED with emission peak at 761 nm
Journal
Chemical Engineering Journal
Journal Volume
452
Date Issued
2023-01-15
Author(s)
Tai, Jing Wen
Tang, Yukun
Zhang, Kai
Yang, Chen Zong
Pan, Ze Hui
Lin, Yu Ching
Shih, Yu Wei
Chen, Chia Hsun
Chiu, Tien Lung
Wang, Chuan Kui
Fan, Jian
Abstract
Near infrared (NIR) emitters have attracted much attention due to their advanced application in biomedical sensing/imaging, and telecommunications. However, the development of efficient NIR thermally activated delayed fluorescence (TADF) emitters with the emission over 750 nm is still a challenge. Herein two Y-shaped NIR TADF molecules (Py-TPA and Py-CN-TPA) were introduced. The inclusion of pyridine unit in these two emitters not only extended the conjugated system but also increased the molecular aspect ratios, thereby leading to their high horizontal ratio of emitting dipole orientation (Θ//). In addition, the NIR emitter showed a low Huang-Rhys (HR) factor in thin film relative to that in solution, indicating a low non-radiative transition rate and a high photoluminescent quantum yield (PLQY). Consequently, TADF OLED based on Py-TPA demonstrated a record-high external quantum efficiency (EQE) of 22.2% at 726 nm, 16.3% at 747 nm, and 13.2% at 761 nm.
Subjects
Horizontal ratio | Near-infrared | OLED | Thermally activated delayed fluorescence
SDGs
Publisher
ELSEVIER SCIENCE SA
Type
journal article