Highly efficient deep-blue organic light-emitting diodes based on pyreno[4,5-<i>d</i>]imidazole-anthracene structural isomers

Liu, Hui; Kang, Liangliang; Li, Jinyu; Liu, Futong; He, Xin; Ren, Shenghong; Tang, Xiangyang; Lv, Changli; Lü, Ping

doi:10.1039/c9tc02990g

Cited by 45 publications

(23 citation statements)

References 52 publications

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“…[18][19][20] Because of excellent thermal stability, efficient blue light emission, and high mobility of charge carrier, pyrene has emerged as a very appealing chromophore for blue OLEDs, which are urgently needed for full-color displays. [21][22][23][24][25] External quantum efficiency (η ext ) is a crucial parameter for the characterization of OLED performance. The theoretical value of η ext can be calculated by the following equation:…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Blue Organic Light-Emitting Diode Based on a Pyrene[4,5- d ]Imidazole-Pyrene Molecule

et al. 2022

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Organic light-emitting diodes (OLEDs), which have been recently utilized in some flat-panel display screens such as mobile phones and televisions, show many merits, including light weight, high flexibility, energy preservation, and so forth, and are considered the next-generation displays and solid-state lightings. Blue-emitting materials that can be applied in nondoped OLEDs with little efficiency roll-offs at high brightness are of great importance. Here, a highly efficient, blue-emitting material, 9-phenyl-10-(4-(pyren-1-yl)phenyl)-9H-pyreno [4,5-d]imidazole (PyPI-Py), is achieved using pyrene [4,5-d]imidazole and pyrene as the weak electron donor and electron acceptor, respectively. The nondoped blue OLED exhibits excellent performance with a maximum brightness of 75,687 cd m −2 , a maximum current efficiency of 13.38 cd A −1 , and a maximum external quantum efficiency (η ext ) of 8.52%. Moreover, the η ext is maintained at 8.35% and 8.05% at a brightness of 10,000 and 50,000 cd m −2 , respectively, displaying extremely small efficiency roll-offs of 2.0% and 5.5%.The device characteristics are among the highest values for nondoped blue OLEDs and correspond to the best performance obtained for nondoped pyrene-based blue OLEDs. The superior performance is attributed to the proper donor-acceptor design strategy which results in a quasi-equivalent hybrid local and charge-transfer excited state with the maximum generation of an 82% fraction of singlet excitons.

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Section: Introductionmentioning

confidence: 99%

Highly Efficient Blue Organic Light-Emitting Diode Based on a Pyrene[4,5- d ]Imidazole-Pyrene Molecule

et al. 2022

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“…Further, anthracene possesses appropriate wide band gap whiche nsures the blue emission of its derivatives. [12] DPAC is introduced as aw eak electron donor group which is connected with anthracene through ab ridging benzene. DPAC has higherh ighest occupied molecular orbital (HOMO)t han anthracene to effectively reduce hole injection barrieri ni ts devices.…”

Section: Introductionmentioning

confidence: 99%

Efficient Nondoped Pure Blue Organic Light‐Emitting Diodes Based on an Anthracene and 9,9‐Diphenyl‐9,10‐dihydroacridine Derivative

Ren

Liu

et al. 2019

Chemistry An Asian Journal

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Organic light-emitting diodes (OLEDs) have been greatly developed in recent years owing to their abundant advantages for full-color displays and general-purposel ightings. Blue emitters not only provide one of the primary colors of the RGB (red, green and blue) display system to reduce the powerc onsumption of OLEDs, but are able able to generate light of all colors, includingb lue, green, red, and white by energy transfer processes in devices. However,i t remains ac hallenge to achieve high-performance blue electroluminescence, especially for nondoped devices.I nt his paper,w ereportablue light emitting molecule, DPAC-AnPCN, which consists of 9,9-diphenyl-9,10-dihydroacridine and p-benzonitrile substituted anthracenem oieties. The asymmetrically decoration on anthracene with different groups on its 9a nd 10 positions combines the merits of the respective constructingu nits and endows DPAC-AnPCN with pure blue emission, high solid-statee fficiency,g ood thermal stabilitya nd appropriate HOMO and LUMO energy levels. Furthermore, DPAC-AnPCN can be appliedi nanondoped device to effectively reduce the fabrication complexity and cost. The nondoped device exhibits pure blue electroluminescence( EL) locating at 464 nm with CIE coordinates of (0.15, 0.15). Moreover, it maintains high efficiency at relatively high luminescence. The maximum externalq uantum efficiency (EQE) reaches 6.04 %a nd still remains 5.31% at the luminanceo f1 000 cd m À2 showing av ery small efficiency roll-off.

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“…Therefore, the electro-optical conversion efficiency of the fluorescent molecule-based OLED is only 25% at most. Although, several bright ideas currently realize high efficiency of FOLED by employing triplet-triplet annihilation (TTA), 26,27 TADF, 24,28,29 and hot exciton assisted singlet harvest, 30,31 the operational lifetime of blue FOLEDs is still at least one order of magnitude shorter than that of the green and red devices (Table 1). Table 2 summarizes some laboratory works with repeatable experiment details.…”

Section: Overview On the Lifetime Studies Of Blue Oledsmentioning

confidence: 99%

Degradation Mechanisms in Blue Organic Light-Emitting Diodes

et al. 2020

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An organic light-emitting diode (OLED) is required to exhibit long-time operation without degradation as an inorganic LED. Sufficiently long operation time has been demonstrated for green-and red-emitting OLEDs. However, a blue device that is important for full-color display and lighting exhibits a much shorter operational lifetime than the other color devices. The short lifetime is mainly attributed to the molecular dissociation and the defects and radical species formation through various unimolecular and bimolecular processes, including direct photolysis, exciton-exciton interaction, and exciton-polaron interaction, and so on. Different novel techniques of chemistry and physics have been employed for blue devices to suppress the degradation process induced by high-energy excitons. A deep understanding of the degradation mechanism is still needed for all three kinds of blue OLEDs employing fluorescence, phosphorescence, and thermally active delayed fluorescence. In this brief review, we introduce and discuss several degradation mechanisms for these three kinds of OLEDs.

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Highly efficient deep-blue organic light-emitting diodes based on pyreno[4,5-d]imidazole-anthracene structural isomers

Abstract: By integrating PyI with anthracene, two high-efficiency blue emitters C-BPyIA and N-BPyIA are obtained. Especially, N-BPyIA exhibits decent device performance with an EQEmax of 7.67% in the deep blue region.

Cited by 45 publications

References 52 publications

Highly Efficient Blue Organic Light-Emitting Diode Based on a Pyrene[4,5- d ]Imidazole-Pyrene Molecule

Highly Efficient Blue Organic Light-Emitting Diode Based on a Pyrene[4,5- d ]Imidazole-Pyrene Molecule

Efficient Nondoped Pure Blue Organic Light‐Emitting Diodes Based on an Anthracene and 9,9‐Diphenyl‐9,10‐dihydroacridine Derivative

Degradation Mechanisms in Blue Organic Light-Emitting Diodes

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