Efficient TADF polymer with optimized molecular structure and interaction for constructing solution-processed hybrid white OLEDs with EQE above 26%

Cao, Qingpeng; Zhang, Wenhao; Xu, Hui; Wang, Jiayi; Pei, Ming; Qian, Youqiang; Zhou, Tao; Zhang, Kaizhi; Ban, Xinxin

doi:10.1016/j.cej.2023.143088

Cited by 5 publications

(1 citation statement)

References 41 publications

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“…At present, TADF small molecules have been well developed, − whereas high-performance TADF conjugated polymers are still under development. , It is certainly difficult for TADF polymers to completely inherit the excellent properties of TADF small molecules after being embedded into polymers. Therefore, it is necessary to deeply study the structure–property relationship of TADF conjugated polymers.…”

Section: Introductionmentioning

confidence: 99%

Adjusting the Electron-Withdrawing Ability of Acceptors in Thermally Activated Delayed Fluorescence Conjugated Polymers for High-Performance OLEDs

Guo,

Zhao,

Hua

et al. 2023

ACS Appl. Mater. Interfaces

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Constructing high-performance solution-processed organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) conjugated polymers remains a challenging issue. The electron-withdrawing ability of acceptors in TADF units significantly affects the TADF properties of the conjugated polymers. Herein, we have designed three TADF conjugated polymers, in which phenoxazine donors and anthracen-9(10H)-one acceptors are incorporated into the polymeric backbones and side chains, respectively, and the carbazole derivative is copolymerized as the host. By incorporating different heteroatoms, such as nitrogen, oxygen, or sulfur, with slightly different electronegativities into anthracen-9(10H)-one, the effect of the electron-withdrawing ability of the acceptor on the performance of conjugated TADF polymer-based OLEDs is thus systematically studied. It is found that the introduction of a nitrogen atom can enhance the spin−orbital coupling and RISC process due to the modulated energy levels and nature of the excited states. As a result, the solution-processed OLEDs based on the prepared polymer p-PXZ-XN display an excellent comprehensive performance with an EQE max of 17.6%, a low turn-on voltage of 2.8 V, and a maximum brightness of 14750 cd m −2 . Notably, the efficiency roll-off is quite low, maintaining 15.1% at 1000 cd m −2 , 12.1% at 3000 cd m −2 , and 6.1% at 10000 cd m −2 , which ranks in the first tier among the reported TADF conjugated polymers. This work provides a guideline for constructing high-efficiency TADF polymers.

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Section: Introductionmentioning

confidence: 99%

Adjusting the Electron-Withdrawing Ability of Acceptors in Thermally Activated Delayed Fluorescence Conjugated Polymers for High-Performance OLEDs

Guo,

Zhao,

Hua

et al. 2023

ACS Appl. Mater. Interfaces

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Color‐Tunable White Circularly Polarized Electroluminescence Triggered Using Chiral Co‐Assembly‐Sensitized Strategy

Zhang,

Tian,

et al. 2024

Laser & Photonics Reviews

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White circularly polarized organic light‐emitting diodes (CP‐WOLEDs) are central to prospective 3D displays and lighting sources. However, owing to the unwanted charge trapping effect and inefficient chirality transfer, the development of CP‐WOLEDs with a high color rendering index (CRI) and large dissymmetry factor (gEL) is challenging. Herein, a pioneering strategy of chiral co‐assembly‐sensitized circularly polarized luminescence (CCS‐CPL) is proposed for improving the performance of white circularly polarized electroluminescence (CP‐EL). Chiral co‐assembled sensitizers ((S‐/R‐Cz)0.2‐(I‐P)0.8) are smartly developed using π–π stacking interactions between the chiral binaphthyl derivatives (S‐/R‐Cz) and achiral conjugated pyrene‐based polymer (I‐P) in a molar ratio of 1:4. Using the chiral co‐assembly‐sensitized strategy on achiral aggregation‐induced emission (AIE) dyes for emitting layers (EMLs) of OLEDs, full‐color achiral AIE‐active dyes can be sensitized by chiral co‐assembly (S‐/R‐Cz)0.2‐(I‐P)0.8. The color‐tunable white CP‐EL performance can be achieved at the CIE coordinates of (0.33, 0.33) with an ultrahigh CRI of 93 and a large gEL value up to 0.071. This study thus provides a valuable guidance for CCS‐type CP‐WOLEDs.

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Creation of High‐Quality Deep‐Blue AIE Emitter with a Crossed Long‐Short Axis Structure for Efficient and Versatile OLEDs

Lou,

Li,

Guo

et al. 2023

Small

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Developing deep‐blue emitters for organic light‐emitting diodes (OLEDs) is critical but challenging, which requires a good balance between light color, exciton utilization, and photoluminescence quantum yield (PLQY) of solid film. Herein, a high‐quality deep‐blue emitter, abbreviated 2TriPE‐CzMCN, is designed by introducing an aggregation‐induced emission (AIE) group into a crossed long‐short axis (CLSA) skeleton. Theoretical and experimental investigations reveal that the CLSA molecular design can achieve a balance between deep‐blue emission and triplet‐excitons utilization, while the high PLQY of the solid film resulting from the AIE feature helps to improve the performance of OLEDs. Consequently, when 2TriPE‐CzMCN is used as the emitting dopant, the OLED exhibits a deep‐blue emission at 430 nm with a record‐high maximum external quantum efficiency (EQE) of 8.84%. When 2TriPE‐CzMCN serves as the host material, the sensitized monochrome orange and two‐color white OLEDs (WOLEDs) realize high EL performances that exceed the efficiency limit of conventional fluorescent OLEDs. Moreover, high‐performance three‐color WOLEDs with a color rendering index (CRI) exceeding 90 and EQE up to 18.08% are achieved by using 2TriPE‐CzMCN as the blue‐emitting source. This work demonstrates that endowing CLSA molecule with AIE feature is an effective strategy for developing high‐quality deep‐blue emitters, and high‐performance versatile OLEDs can be realized through rational device engineering.

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Efficient TADF polymer with optimized molecular structure and interaction for constructing solution-processed hybrid white OLEDs with EQE above 26%

Cited by 5 publications

References 41 publications

Adjusting the Electron-Withdrawing Ability of Acceptors in Thermally Activated Delayed Fluorescence Conjugated Polymers for High-Performance OLEDs

Adjusting the Electron-Withdrawing Ability of Acceptors in Thermally Activated Delayed Fluorescence Conjugated Polymers for High-Performance OLEDs

Color‐Tunable White Circularly Polarized Electroluminescence Triggered Using Chiral Co‐Assembly‐Sensitized Strategy

Creation of High‐Quality Deep‐Blue AIE Emitter with a Crossed Long‐Short Axis Structure for Efficient and Versatile OLEDs

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