A linear deep-blue bipolar fluorescent material with the CIEy &lt; 0.065 serving as the emitter and host for high-performance monochromatic and hybrid white OLEDs

Peng, Lizeng; Huo, Yumiao; He, Shuyao; Liu, Yuchao; Ren, Zhongjie; Ying, Shian; Yan, Shouke

doi:10.1039/d2tc01928k

Cited by 9 publications

(4 citation statements)

References 58 publications

(77 reference statements)

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“…PPISCF and PPISPhCz show the LE-like emission with a pronounced fine vibration structure in low and middle polar solvents, while the broadened and structureless emission appears in high polar solvents (acetonitrile), belonging to CT-dominated characters. On the basis of Lippert–Mataga model, their Stokes shift versus orientation polarizability curves appear two-section linear relationships in different polar solvents (Figure S9 of the Supporting Information), attributing to the typical characteristic of HLCT excited state, which is consistent with the theoretical calculations. Furthermore, the fluorescence and phosphorescence spectra at 77 K were obtained in dilute THF solution (Figure c).…”

Section: Resultsmentioning

confidence: 99%

“…Until now, although some OLEHMs have been reported based on the tetraphenylbenzene, 24 benzoxazole, 21,25 [1,2,4]triazolo [1,5-a]pyridine, 26,27 phenanthroimidazole, 28−31 phenylcarbazole, 31 diphenylsulfone, 32 and other functional groups, 33 there are still significant challenges to achieving the deep-blue OLEHMs meeting the above requirements. 22,34,35 Herein, we propose a peripheral auxiliary group strategy to construct bipolar deep-blue OLEHMs (PPISCF and PPISPhCz) with hybridized local and charge-transfer (HLCT) excited-state characters, realizing the goal of killing two birds with one stone: the introduction of a peripheral group not only makes the OLEHMs maintain a relatively balanced bipolar transporting property but also effectively improves the thermal stability and fluorescence efficiency under the prerequisite of deep-blue emission. As a result, compound PPISPhCz realized a high T g of 192 °C, PLQYs of ∼100 and 66.2% in solution and neat films, as well as an acceptable EQE of 5.34% in the nondoped OLED with the CIE coordinates of (0.157, 0.077).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the exciplex between the OLEHM and phosphors should not be formed to avoid the generation of unwanted emission. Until now, although some OLEHMs have been reported based on the tetraphenylbenzene, benzoxazole, , [1,2,4]triazolo[1,5- a ]pyridine, , phenanthroimidazole, − phenylcarbazole, diphenylsulfone, and other functional groups, there are still significant challenges to achieving the deep-blue OLEHMs meeting the above requirements. ,, …”

Section: Introductionmentioning

confidence: 99%

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Bipolar Deep-Blue Host for High-Performance Multicolor OLEDs by Peripheral Auxiliary Group Strategy

Lv,

Li,

Song

et al. 2023

ACS Appl. Opt. Mater.

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Developing a multifunctional bipolar deep-blue organic fluorophore acting as an emitter and host for long-wavelength emissive phosphors simultaneously is important and urgently needed for organic light-emitting diodes (OLEDs) in the application of full-color displays. However, it remains a big challenge to resolve the contradictions between the inherent wide band gap of deep-blue materials and charge carrier injection/transporting, luminescence efficiency, and thermal stability. In this work, we proposed a peripheral auxiliary group strategy to construct the multifunctional bipolar dibenzothiophene-phenanthroimidazole-based materials (PPISCF and PPISPhCz), realizing the goal of killing two birds with one stone: the thermal stability and fluorescence efficiency can be improved greatly while maintaining deep-blue emission and bipolar transporting abilities effectively. By comparison, phenylcarbazolemodified PPISPhCz shows a high glass transition temperature of 192 °C, as well as high and balanced electron−hole transporting properties. Consequently, the PPISPhCz-based nondoped device shows the color coordinates of (0.157, 0.077) and an external quantum efficiency (EQE) up to 5.34%. Using PPISPhCz as a host for green, yellow, and red phosphors, the OLEDs show the maximum EQEs of 18.90, 21.97, and 23.52%, respectively. Meanwhile, the fluorescent/phosphorescent hybrid white OLED with PPISPhCz as an emitter and host exhibits an excellent power efficiency and EQE of 74.72 lm W −1 and 23.77%, respectively. This study offers a viable strategy to blossom multifunctional deep-blue host materials by a peripheral auxiliary group, which is instrumental in creating simple and highperformance full-color OLEDs.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bipolar Deep-Blue Host for High-Performance Multicolor OLEDs by Peripheral Auxiliary Group Strategy

Lv,

Li,

Song

et al. 2023

ACS Appl. Opt. Mater.

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“…In these bipolar structures, it is difficult to realize deep blue because intramolecular charge transfer between donors and acceptors effectively reduces the band gap. However, deep blue can be achieved using the following three strategies (i-iii): (i) enhancement of steric hinderance between donors and acceptors; (ii) maintenance of an appropriate distance between the two moieties using a donor-spacer-acceptor type; and/or (iii) reduction of electron donating and accepting capacities [5][6][7][8]. Without these strategies, it is difficult to achieve deep-blue emission with bipolar materials.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Electrical Properties of a New Bipolar Material Using Spacer Moiety

Jo,

Park,

Kwon

et al. 2024

Applied Sciences

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To develop a deep-blue emitter, a molecule with bipolar characteristics was designed as a donor-spacer-acceptor type, in which 9-(4-(4,6-diphenyl-1),3,5-triazin-2-yl)-2,5-dimethylphenyl)-9H-carbazole (DTPCZ)—with carbazole as an electron donating group and a diphenyl triazine moiety as an electron accepting group—was successfully synthesized. The photoluminescence (PL) maxima of DTPCZ were 421 nm in the solution state and 425 nm in the film state, indicating emission in the deep-blue region. DTPCZ also exhibited high thermal stability, with a degradation temperature of 349 °C. To confirm the electroluminescence (EL) characteristics, DTPCZ was applied as a dopant at 10, 20, and 30 wt% in a blue-fluorescent organic light-emitting diode (OLED) device. The highest efficiency was achieved using the 20 wt% doped device, with a current efficiency of 1.2 cd/A, an external quantum efficiency of 2.3%, and a Commission Internationale de l’Eclairage proceedings y-value of 0.06. Thus, deep-blue emission could be realized in the film state. These molecular design strategies can be applied to various fields, such as organic semiconductors.

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High and Balanced Bipolar‐Transporting Deep‐Blue HLCT Material for Efficient Monochrome and White OLEDs based on a Simple Phenanthroimidazole‐Dibenzothiophene Derivative

Lv,

Song,

et al. 2023

Advanced Optical Materials

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The irreconcilable contradiction between wide bandgap and charge carriers injection/transport in deep‐blue organic electroluminescence materials is one of the largest bottlenecks restricting the development of organic light‐emitting diodes (OLEDs). Here, a multifunctional deep‐blue hybridized local and charge‐transfer material containing a phenanthroimidazole‐dibenzothiophene derivative that can act as an emitter as well as a host for phosphorescent OLEDs is reported. Owing to its high and balanced bipolar‐transporting ability, remarkable fluorescence efficiency, and suitable triplet energy level, the deep‐blue device with it as a neat emitter provides an external quantum efficiency (EQE) of 6.68%, while yellow and red phosphorescent OLEDs offer the EQEs of 25.35% and 22.19%, respectively. All of them exhibit low‐efficiency roll‐off characteristics. What's more amazing is that the fluorescent/phosphorescent hybrid white OLEDs achieve high power efficiencies and EQEs over 95.9 lm W−1 and 26.8%, and the values are still higher than 77.7 lm W−1 and 25.6% at the high luminance of 1000 cd m−2.

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A linear deep-blue bipolar fluorescent material with the CIEy < 0.065 serving as the emitter and host for high-performance monochromatic and hybrid white OLEDs

Abstract: A linear deep-blue HLCT material P2MPC served as the emitter and host in high-performance monochromatic and hybrid white OLEDs.

Cited by 9 publications

References 58 publications

Bipolar Deep-Blue Host for High-Performance Multicolor OLEDs by Peripheral Auxiliary Group Strategy

Bipolar Deep-Blue Host for High-Performance Multicolor OLEDs by Peripheral Auxiliary Group Strategy

Synthesis and Electrical Properties of a New Bipolar Material Using Spacer Moiety

High and Balanced Bipolar‐Transporting Deep‐Blue HLCT Material for Efficient Monochrome and White OLEDs based on a Simple Phenanthroimidazole‐Dibenzothiophene Derivative

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