Non-interlayer and color stable WOLEDs with mixed host and incorporating a new orange phosphorescent iridium complex

Guo, Lifeng; Zhang, Xunlu; Zhuo, Minjie; Liu, Chen; Chen, Wangyang; Mi, Baoxiu; Song, Juan; Li, Yonghua; Gao, Zhiqiang

doi:10.1016/j.orgel.2014.08.034

Cited by 14 publications

(4 citation statements)

References 31 publications

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“…Pyridazine and its derivatives have received arising attention these past few years, as building blocks in organic semiconductors for OFET, solvate-chromic/fluorescent sensors, and liquid crystal materials as well as efficient ligands for strong phosphorescent iridium complexes. − As a six-member heterocyclic aromatic ring, pyridazine comprises two adjacent sp 2 N. When compared with other monocyclic aromatic ring analogues of benzene without N atom and pyridine with one N atom, pyridazine is not only more electron accepting but also more polar, beneficial to its usage as electron acceptor in D–A type materials. However, for optoelectronic application, to the best of our knowledge, except for the compounds reported in ref , which were used as a semiconductor in the OFET device, pyridazine incorporated D–A bipolar materials are rare in the literature.…”

Section: Introductionmentioning

confidence: 99%

Structure–Property Study on Two New D–A Type Materials Comprising Pyridazine Moiety and the OLED Application as Host

Zhang

et al. 2017

ACS Appl. Mater. Interfaces

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In this paper, two new pyridazine based donor-acceptor type materials, i.e., 3CzPyaPy: 9,9'-(3-(6-(9H-carbazol-9-yl)pyridazin-3-yl)pyridine-2,6-diyl)bis(9H-carbazole) and 4CzPyPyaPy: 3,6-bis(2,6-di(9H-carbazol-9-yl)pyridin-3-yl)pyridazine, were synthesized with high yields. These two materials exhibited strong absorption/emission with high molar extinction coefficients and moderate photoluminescence quantum yield. The glass transition temperature of 3CzPyaPy was detected to be as high as 131 °C, showing its high thermal stability. Although the absorption energies and oxidation/reduction behaviors of the two materials were similar, the emission from 4CzPyPyaPy with longer effective-conjugation length presented hypsochromic shift both in films and in dilute solutions, contradicting to the common sense. The single crystal structure study disclosed their different space stretching and packing: 3CzPyaPy was twisted in larger angles and adopted dimerlike packing, while 4CzPyPyaPy showed smaller torsion angles and exhibited slipped herringbone packing. The dimerlike packing in 3CzPyaPy is responsible for its bathochromic shift of emission in solid state, while its unsymmetrical molecular structure accounts for that in solution. We believe that the unsymmetrical molecular structure of 3CzPyaPy is partially responsible for its high thermal-stability and also responsible for its HOMO dispersion which renders it slightly more difficult to oxidize. 3CzPyaPy was proved to be a bipolar-transport material and when served as a phosphor host, a green phosphorescent device achieved maximum efficiencies of 54.0 cd A, 42.4 lm W, and 17.7%, which are among the best with nonoptimized device structure, demonstrating its great potential for optoelectronic application. Furthermore, the new synthesized pyridazine derivatives and the corresponding structural and molecular-packing influences on material properties give a new insight into molecule tailoring.

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Section: Introductionmentioning

confidence: 99%

Structure–Property Study on Two New D–A Type Materials Comprising Pyridazine Moiety and the OLED Application as Host

Zhang

et al. 2017

ACS Appl. Mater. Interfaces

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“…The charge carrier transport could be significantly affected by the mixed ratio of the hole transport material and electron transport material in the mixed-host [25,26]. By using the mixed-host structure, the performances of phosphorescent devices such as efficiency, color coordinate, and current density, will be expected to be managed.…”

Section: Resultsmentioning

confidence: 99%

Color-stable white phosphorescent organic light-emitting diodes based on double bipolar mixed-host layer

Zhang

Song

Gao

et al. 2020

J. Phys. D: Appl. Phys.

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In this study, we demonstrated high-efficiency white phosphorescent organic light emitting diodes with stable spectra based on the mixed-host emission layer. By employing a mixed-host system consisting of the hole transport material (4, 4'-N, N' -dicarbazole) biphenyl and electron transport material 1, 3, 5-tris (2-N-pheylbenzimidazolyl) benzene in double emission layers, realizing warm white organic light-emitting diodes characterized by peak efficiencies of 47.24 cd A−1 and 39.12 lm W−1 with the Commission International de L’Eclairage coordinates variations from (0.428, 0.470) to (0.427, 0.471) when the luminance varies from 1000 to 10 000 cd m−2.

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“…Under high current density, the lifetime and efficiency of OLEDs often accelerate degradation [112]. Tandem WOLEDs are proposed to alleviate this problem, which can obtain improvements in lifetime and brightness [113,114].…”

Section: Phosphorescent Doping-free Woleds With Uemlsmentioning

confidence: 99%

Progress in Research on White Organic Light-Emitting Diodes Based on Ultrathin Emitting Layers

Zhao,

Hu,

Kong

et al. 2024

Micromachines

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White organic light-emitting diodes (WOLEDs) hold vast prospects in the fields of next-generation displays and solid-state lighting. Ultrathin emitting layers (UEMLs) have become a research hotspot because of their unique advantage. On the basis of simplifying the device structure and preparation process, they can achieve electroluminescent performance comparable to that of doped devices. In this review, we first discuss the working principles and advantages of WOLEDs based on UEML architecture, which can achieve low cost and more flexibility by simplifying the device structure and preparation process. Subsequently, the successful applications of doping and non-doping technologies in fluorescent, phosphorescent, and hybrid WOLEDs combined with UEMLs are discussed, and the operation mechanisms of these WOLEDs are emphasized briefly. We firmly believe that this article will bring new hope for the development of UEML-based WOLEDs in the future.

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Non-interlayer and color stable WOLEDs with mixed host and incorporating a new orange phosphorescent iridium complex

Cited by 14 publications

References 31 publications

Structure–Property Study on Two New D–A Type Materials Comprising Pyridazine Moiety and the OLED Application as Host

Structure–Property Study on Two New D–A Type Materials Comprising Pyridazine Moiety and the OLED Application as Host

Color-stable white phosphorescent organic light-emitting diodes based on double bipolar mixed-host layer

Progress in Research on White Organic Light-Emitting Diodes Based on Ultrathin Emitting Layers

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