Modifications of Pyridine-3,5-dicarbonitrile Acceptor for Highly Efficient Green-to-Red Organic Light-Emitting Diodes

Deng, Shin‐Tarng; Chen, Yi-Kuan; Lei, Jian; Jayakumar, Jayachandran; Ko, Chang‐Lun; Hung, Wen‐Yi; Wu, Tien-Lin; Cheng, Chien‐Hong

doi:10.1021/acsami.3c05243

Cited by 5 publications

References 43 publications

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Introduction of a Chiral Biphenanthrene‐Diol Unit to Achieve Circularly Polarized Thermally Activated Delayed Fluorescence

Lei,

Lou,

Chen

et al. 2024

Chemistry An Asian Journal

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Circularly polarized luminescence (CPL) materials are promising candidates for future display technology. However, such highly efficient emitters suffer from the issues of difficult chiral separation and low photoluminescence quantum yield (PLQY). In this work, the chiral 4,4′‐biphenanthrene‐3,3′‐diol (BIPOL) unit was introduced into a thermally activated delayed fluorescence (TADF) framework for the first time. We presented two series of enantiomers, R/S‐o‐DCzBPNCN and R/S‐p‐DCzBPNCN, and the synthesis of enantiopure BIPOL can be prepared via normal column chromatography. Notably, o‐DCzBPNCN showed narrow singlet‐triplet gap of 0.05 eV, efficient TADF, and high PLQYs of 82 % in doped films. In addition, R/S‐o‐DCzBPNCN exhibited high luminescence dissymmetry factor (gPL) values of −1.94×10−2/+1.91×10−2 in doped films. The strategy of BIPOL introduction offers a new approach to organic emitters with stereospecific synthesis, TADF, and chiroptical properties.

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Introduction of a Chiral Biphenanthrene‐Diol Unit to Achieve Circularly Polarized Thermally Activated Delayed Fluorescence

Lei,

Lou,

Chen

et al. 2024

Chemistry An Asian Journal

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Effective donor and acceptor modifications of carbazole-benzonitrile thermally activated delayed fluorescence molecules enabling high-performance OLEDs

Li,

Ma,

Gao

et al. 2024

Dyes and Pigments

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Strategy of Modulating Nonradiative Decay for Approaching Efficient Thermally Activated Delayed Fluorescent Emitters

Lei,

Chang,

Chen

et al. 2024

J. Phys. Chem. C

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The photoluminescence quantum yield (PLQY) of an emitter reflects the extent of the nonradiative process and significantly influences the performance of the electroluminescent devices. This study presents a new strategy for designing thermally activated delayed fluorescence (TADF) materials based on suppressing nonradiative decay. The substituents and their positions can modulate exciton behavior in a molecule. We modified the diboraanthranene framework with various alkyl substituents as models to explore the strategy for designing donor−acceptor−donor (D−A−D)-type TADF emitters. Experimental results and theoretical simulations indicate that suppressing nonradiative decay can enhance PLQYs and the delayed component (Φ d ) of PLQY. Based on the theory of nonradiative decay, our findings suggest that the local C−H stretching modes originating from the alkyl groups are the main contributors to the nonradiative decay rates of the first excited singlet state (k nr,S ). Notably, our simulations demonstrate that the PLQYs of the five emitters are increased by alkyl deuteration and can be nearly optimized to 100% through perdeuteration. MECzDBA-and EECzDBA-based green organic light-emitting diodes (OLEDs) achieve superior external quantum efficiencies of 29.4 and 28.6%, respectively, with reduced efficiency roll-off of only 5.1 and 5.2% at 1000 cd m −2 . The outcomes from our study suggest a molecular design strategy that successfully counteracts the nonradiative decay in TADF materials, providing a new direction for creating high-efficiency organic emitters.

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Modifications of Pyridine-3,5-dicarbonitrile Acceptor for Highly Efficient Green-to-Red Organic Light-Emitting Diodes

Cited by 5 publications

References 43 publications

Introduction of a Chiral Biphenanthrene‐Diol Unit to Achieve Circularly Polarized Thermally Activated Delayed Fluorescence

Introduction of a Chiral Biphenanthrene‐Diol Unit to Achieve Circularly Polarized Thermally Activated Delayed Fluorescence

Effective donor and acceptor modifications of carbazole-benzonitrile thermally activated delayed fluorescence molecules enabling high-performance OLEDs

Strategy of Modulating Nonradiative Decay for Approaching Efficient Thermally Activated Delayed Fluorescent Emitters

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