A novel bipolar D–π–A type phenanthroimidazole/carbazole hybrid material for high efficiency nondoped deep-blue organic light-emitting diodes with NTSC CIE<sub>y</sub> and low efficiency roll-off

Tan, Yu; Zhao, Zifeng; Shang, Liang; Liu, Yang; Chen, Wei; Li, Jiayi; Wei, Huibo; Liu, Zhiwei; Bian, Zuqiang; Huang, Chunhui

doi:10.1039/c7tc04089j

Cited by 53 publications

(25 citation statements)

References 51 publications

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“…In the past decades, organic light-emitting diodes (OLEDs) have become increasingly irreplaceable for their excellent potential in commercial full-color flat panel displays and general lighting applications. [1][2][3][4][5] In general, traditional fluorescent OLEDs have been widely used in commercial devices due to their advantages of high color purity and long operational lifetime. However, they can only harvest excitons in the singlet state, which is equal to 25 % of all the electronically generated excitons.…”

Section: Introductionmentioning

confidence: 99%

Versatile Host Materials for Highly‐Efficient Green, Red Phosphorescent and White Organic Light‐Emitting Diodes

et al. 2019

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To build up efficient host materials, two novel organic small molecules ICz‐PPI and 2ICz‐PPI were designed and synthesized, in which phenanthro[9,10‐d]imidazole (PI) is proposed as a potential luminophore with high stability, while the indolo[3,2,1‐jk]carbazole (ICz) has a high triplet energy and excellent thermal stability. Both exhibited weak intramolecular charge transfer, high decomposition temperature (Td) and high quantum yield. ICz‐PPI and 2ICz‐PPI can act as the emitting layer in non‐doped organic light‐emitting diodes (OLEDs), which achieved an external quantum efficiency (EQE) of 2.47 and 1.94 % with CIE coordinates of (0.153, 0.121) and (0.161, 0.102), respectively. In addition, the high triplet energy allows them to be used as hosts for phosphorescent OLEDs (PhOLEDs). Accordingly, high performance for green (62.5 cd A−1, 70.9 lm W−1, 17.8 %) and red (25.7 cd A−1, 26.9 lm W−1, 19.4 %) had been achieved from the ICz‐PPI‐based PhOLED. Particularly, the ICz‐PPI‐based red PhOLED showed surprisingly low roll‐off and maintained an EQE of 14.9 % at 10 000 cd m−2. Furthermore, an ICz‐PPI‐based white OLED (WOLED) exhibited warm white light (CIEx,y=(0.427, 0.468)) and high efficiencies with a CEmax of 31.8cd A−1, PEmax of 37.0lm W−1 and EQEmax of 14.4 %.

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Section: Introductionmentioning

confidence: 99%

Versatile Host Materials for Highly‐Efficient Green, Red Phosphorescent and White Organic Light‐Emitting Diodes

et al. 2019

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“…[54][55][56] Thus, the "hot exciton" channel may serve to explain why IP-An-PPI can break the theoretical limitation of spin-statistics of common fluorescent materials and have a large ratio of singlet exciton utilization. [57] As shown in Figure 6, considering the large energy splitting (1.359 eV) between S 1 and T 1 , the high efficiency could not be explained by the TADF mechanism. The internal conversion (IC) process between T 1 and T 2 which had a large energy gap of 0.9862 eV may be forbidden owing to the energy-gap law.…”

Section: Devicementioning

confidence: 86%

Constructing Highly Efficient Blue OLEDs with External Quantum Efficiencies up to 7.5 % Based on Anthracene Derivatives

Zheng

Huang

Yang

et al. 2021

Chemistry A European J

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Acquiring desirable device performance with deepblue color purity that fulfills practical application requirements is still a challenge. Bipolar fluorescent emitters with hybrid local and charge transfer (HLCT) state may serve to address this issue. Herein, by inserting anthracene core in the deep-blue building blocks, the authors successfully developed two highly twisted D-π-A fluorescent emitters, ICz-An-PPI and IP-An-PPI, featuring different acceptor groups. Both exhibited superb thermal stabilities, high photo luminescent quantum yields and excellent bipolar transport capabilities. The nondoped OLEDs using ICz-An-PPI and IP-An-PPI as the emitting layers showed efficient blue emission with an external quantum efficiency (EQE max ) of 4.32 % and 5.41 %, and the CIE coordinates of (0.147, 0.180) and (0.149, 0.150), respectively. In addition, the deep blue doped device based on ICz-An-PPI was achieved with an excellent CE max of 5.83 cd A À 1 , EQE max of 4.6 % and the CIE coordinate of (0.148, 0.078), which is extremely close to the National Television Standards Committee (NTSC) standard. Particularly, IP-An-PPI-based doped device had better performance, with an EQE max of 7.51 % and the CIE coordinate of (0.150, 0.118), which was very impressive among the recently reported deep-blue OLEDs with the CIE y < 0.12. Such high performance may be attributed to the hot exciton HLCT mechanism via T 7 to S 2 . Our work may provide a new approach for designing high-efficiency deepblue materials.

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“…A 3.02% EQE and (0.167, 0.056) true deep-blue CIE coordinates were obtained in the non-doped OLED using M2 as the EML. By introducing the CN group, Huang reported the synthesis, photophysical properties, thermostability, and electrochemical characterization of two PI/Czbased compounds (CBPMCN and CPBPMCN) [50]. The non-doped devices based on CPBPMCN exhibited a deep-blue EL with (0.15, 0.08) CIE coordinates, which is extremely close to the NTSC standard blue.…”

Section: Pi-based Fluorescent Materialsmentioning

confidence: 94%

Imidazole derivatives for efficient organic light-emitting diodes

Zhuang

Pan

et al. 2020

Journal of Information Display

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Since the first development of organic light-emitting diodes (OLEDs) in 1987, imidazole derivatives, mainly including phenanthroimidazole (PI) and benzimidazole (BI), have increasingly attracted attention. Their strong electron-withdrawing properties make them suitable for emitters, hosts, and electron-transporting materials (ETMs). In this review, an overview of the recent developments regarding OLEDs based on imidazole derivatives, especially the relationship between the molecule structure and the device performance as fluorescent and host materials, is given.

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A novel bipolar D–π–A type phenanthroimidazole/carbazole hybrid material for high efficiency nondoped deep-blue organic light-emitting diodes with NTSC CIE_y and low efficiency roll-off

Abstract: Nondoped OLEDs utilizing a new emitter exhibited EL with NTSC CIEy and high EQEmax (5.80%) with low efficiency roll-off.

Cited by 53 publications

References 51 publications

Versatile Host Materials for Highly‐Efficient Green, Red Phosphorescent and White Organic Light‐Emitting Diodes

Versatile Host Materials for Highly‐Efficient Green, Red Phosphorescent and White Organic Light‐Emitting Diodes

Constructing Highly Efficient Blue OLEDs with External Quantum Efficiencies up to 7.5 % Based on Anthracene Derivatives

Imidazole derivatives for efficient organic light-emitting diodes

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A novel bipolar D–π–A type phenanthroimidazole/carbazole hybrid material for high efficiency nondoped deep-blue organic light-emitting diodes with NTSC CIEy and low efficiency roll-off

Abstract: Nondoped OLEDs utilizing a new emitter exhibited EL with NTSC CIEy and high EQEmax (5.80%) with low efficiency roll-off.

Cited by 53 publications

References 51 publications

Versatile Host Materials for Highly‐Efficient Green, Red Phosphorescent and White Organic Light‐Emitting Diodes

Versatile Host Materials for Highly‐Efficient Green, Red Phosphorescent and White Organic Light‐Emitting Diodes

Constructing Highly Efficient Blue OLEDs with External Quantum Efficiencies up to 7.5 % Based on Anthracene Derivatives

Imidazole derivatives for efficient organic light-emitting diodes

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A novel bipolar D–π–A type phenanthroimidazole/carbazole hybrid material for high efficiency nondoped deep-blue organic light-emitting diodes with NTSC CIE_y and low efficiency roll-off