High‐Performance Ultraviolet Organic Light‐Emitting Diode Enabled by High‐Lying Reverse Intersystem Crossing

Ultraviolet (UV) organic emitters that can open up applications for future organic light‐emitting diodes (OLEDs) are of great value but rarely developed. Here, we report a high‐quality UV emitter with hybridized local and charge‐transfer (HLCT) excited state and its application in UV OLEDs. The UV e...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2021-10, Vol.60 (41), p.22241-22247
Main Authors: Zhang, Han, Li, Ganggang, Guo, Xiaomin, Zhang, Kai, Zhang, Bing, Guo, Xuecheng, Li, Yuxuan, Fan, Jianzhong, Wang, Zhiming, Ma, Dongge, Tang, Ben Zhong
Format: Article
Language:English
Subjects:
Charge transfer
Color
Electroluminescence
Emitters
Excitons
hybridized local and charge-transfer state
Narrowband
OLEDs
Organic light emitting diodes
Purity
Quantum efficiency
record-high EQE
reverse intersystem crossing
Ultraviolet radiation
UV emission
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Summary:Ultraviolet (UV) organic emitters that can open up applications for future organic light‐emitting diodes (OLEDs) are of great value but rarely developed. Here, we report a high‐quality UV emitter with hybridized local and charge‐transfer (HLCT) excited state and its application in UV OLEDs. The UV emitter, 2BuCz‐CNCz, shows the features of low‐lying locally excited (LE) emissive state and high‐lying reverse intersystem crossing (hRISC) process, which helps to balance the color purity and exciton utilization of UV OLED. Consequently, the OLED based on 2BuCz‐CNCz exhibits not only a desired narrowband UV electroluminescent (EL) at 396 nm with satisfactory color purity (CIEx, y=0.161, 0.031), but also a record‐high maximum external quantum efficiency (EQE) of 10.79 % with small efficiency roll‐off. The state‐of‐the‐art device performance can inspire the design of UV emitters, and pave a way for the further development of high‐performance UV OLEDs. Through the proposed long‐short axis molecular design, an HLCT‐type ultraviolet emitter is reported. Benefiting from the features of the low‐lying LE emissive state and high‐lying reverse intersystem crossing process, the ultraviolet OLED furnishes a record‐high EQE of 10.79 %, accompanied by a satisfactory color purity and a small efficiency roll‐off.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.202108540