The structure optimization of phenanthroimidazole based isomers with external quantum efficiency approaching 7% in non-doped deep-blue OLEDs

Zhu, Jie-Ji; Chen, Yuwen; Xiao, Yonghong; Lian, Xin; Yang, Guangsai; Tang, Shan-Shun; Ma, Dongge; Wang, Ying; Tong, Qing‐Xiao

doi:10.1039/c9tc06658f

Cited by 36 publications

(13 citation statements)

References 50 publications

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“…The above results verify that the TADF material‐sensitized CPL devices could realize higher efficiencies and lower operating voltage than the HLCT‐only OLEDs. [ 6a,f,12 ] Especially, the efficiencies roll‐off with respect to CE, PE, and EQE are sufficiently suppressed for HLCT‐based OLEDs upon the usage of TADF sensitizers. [ 5,6e,13 ] Furthermore, CPEL activities of the ( R )‐BBT2TPA‐based OLED were investigated.…”

Section: Resultsmentioning

confidence: 99%

Highly Efficient Sensitized Chiral Hybridized Local and Charge‐Transfer Emitter Circularly Polarized Electroluminescence

Kong

Yang

Liao

et al. 2022

Adv Funct Materials

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This work describes the first hot exciton fluorescent material based on benzo[c][1,2,5]thiadiazole and chiral binaphthol enabling circularly polarized luminescence (CPL) through a chiral perturbation strategy. The new molecular architecture displays CPL, hybridized local and charge transfer (HLCT) properties concurrently. Utilizing it as the emitter, circularly polarized organic light‐emitting diodes (CP‐OLEDs) achieve an external quantum efficiency (EQE) of 7.2% with a good exciton utilization (36%) and a moderate circularly polarized electroluminescence (CPEL) dissymmetry factor (gEL, 2.1 × 10−3). In addition, the CP‐HLCT molecule is sensitized by a thermally activated delayed fluorescence material, significantly ameliorating the efficiency of HLCT fluorescent CP‐OLEDs. Excellent performances of twofold maximum EQE (EQEmax) of 15.3% and 82% exciton utilization are obtained in the sensitized device, regarding an extremely low‐efficiency roll‐off of 2.6% at 1000 cd m−2 as well as CPEL with a gEL value of 2.0 × 10−3.

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Section: Resultsmentioning

confidence: 99%

Highly Efficient Sensitized Chiral Hybridized Local and Charge‐Transfer Emitter Circularly Polarized Electroluminescence

Kong

Yang

Liao

et al. 2022

Adv Funct Materials

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“…Notably, the photoluminescent quantum yield (Φ f ) is high up to unity in DCM solution, using 9,10‐diphenylanthracene as a standard (Φ f = 0.90 in cyclohexane). [ 26 ] And the absolute quantum yield in solid thin film was measured via an integrating sphere apparatus to be 62.1%. Such high Φ f of PHT‐PPI in both solution and solid film is massively conducive to efficient luminescence in the device.…”

Section: Resultsmentioning

confidence: 99%

Effective Energy Transfer for Green, Orange, and Red Phosphorescent Organic Light‐Emitting Diodes Based on a Bipolar Deep‐Blue Emitter with Low Efficiency Roll‐Off at High Brightness

Yang

Zhu

Tang

et al. 2021

Advanced Photonics Research

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Of paramount significance in phosphorescent organic light‐emitting diodes (PHOLEDs) are the facts that Förster resonance energy transfer (FRET) must be sufficient and back energy transfer should be prohibited. Herein, the FRET efficiencies for high‐performance PHOLEDs based on a simple bipolar luminogen 1‐phenyl‐2‐(5′‐phenyl‐[1,1′:3′,1″‐terphenyl]‐4‐yl)‐1H‐phenanthro[9,10‐d]imidazole (PHT‐PPI) with high triplet energy of 2.44 eV are systematically investigated. As a result, with PO‐01 as dopant, the high‐performance orange PHOLED is achieved with maximum external quantum efficiency (EQEmax) of 26.14% and ultrahigh brightness of 152 000 cd m−2, which are the highest reported efficiencies for orange OLEDs with such high brightness. In addition, the green and red PHOLEDs are also fabricated with EQEmax of 15.38% and 16.12%, respectively. Furthermore, the nondoped device based on PHT‐PPI as a deep‐blue emitter is also obtained with an EQEmax of 5.12% and the Commission Internationale de L’Eclairage (CIE) index of (0.15, 0.08). More importantly, the blue, green, orange, and red devices exhibit low efficiency roll‐off, particularly, of which the orange PHOLED is extremely small (<9%) even at the brightness of 10 000 cd m−2.

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“…Their use as emissive layers (EMLs) in multilayer non-doped devices presents true deepblue CIE coordinates of (0.15, 0.06), accompanied by a record-setting performance, with an EQE max of 7.20% for PPI-2TPA and 6.33% for PPI-2NPA. Meanwhile, the isomers TPA-PPI-PBI, TPA-PPI-NPBI, PBI-PPI-TPA, and NPBI-PPI-TPA with multiple donors/acceptors for high-efficiency deep-blue OLEDs were developed by Tong et al [45], and the devices based on TPA-PPI-PBI, TPA-PPI-NPBI, PBI-PPI-TPA, and NPBI-PPI-TPA achieved deep-blue emissions, with (0.15, 0.07), (0.15, 0.07), (0.15, 0.09), and (0.15, 0.05) CIE coordinates and high EQE max values of 4.12, 4.66, 6.88, and 5.59%, respectively. The PBI-PPI-TPA-based device exhibited a negligible efficiency roll-off with a 6.48% EQE at a practical 1000 cd m −2 .…”

Section: Pi-based Fluorescent Materialsmentioning

confidence: 99%

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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The structure optimization of phenanthroimidazole based isomers with external quantum efficiency approaching 7% in non-doped deep-blue OLEDs

Abstract: In this work, four phenanthroimidazole (PI) based isomers TPA-PPI-PBI, TPA-PPI-NPBI, PBI-PPI-TPA and NPBI-PPI-TPA for high-efficiency deep-blue organic light-emitting diodes (OLEDs) have been designed and synthesized.

Cited by 36 publications

References 50 publications

Highly Efficient Sensitized Chiral Hybridized Local and Charge‐Transfer Emitter Circularly Polarized Electroluminescence

Highly Efficient Sensitized Chiral Hybridized Local and Charge‐Transfer Emitter Circularly Polarized Electroluminescence

Effective Energy Transfer for Green, Orange, and Red Phosphorescent Organic Light‐Emitting Diodes Based on a Bipolar Deep‐Blue Emitter with Low Efficiency Roll‐Off at High Brightness

Imidazole derivatives for efficient organic light-emitting diodes

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