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A new concept of host, electroplex host, is developed for high efficiency and long lifetime phosphorescent organic light-emitting diodes by mixing two host materials generating an electroplex under an electric field. A carbazole-type host and a triazine-type host are selected as the host materials to form the electroplex host. The electroplex host is found to induce light emission through an energy transfer process rather than charge trapping, and universally improves the lifetime of red, yellow, green, and blue phosphorescent organic light-emitting diodes by more than four times. Furthermore, the electroplex host shows much longer lifetime than a common exciplex host. This is the first demonstration of using the electroplex as the host of high efficiency and long lifetime phosphorescent organic light-emitting diodes.
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http://dx.doi.org/10.1002/advs.201700608 | DOI Listing |
J Phys Chem Lett
July 2020
Sauvage Center for Molecular Sciences, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, People's Republic of China.
We report the exceptionally long-range charge-transfer-induced electroplex between a neat dendrimer emitter and the adjacent electron-transporting layer (ETL). Interestingly, the electroplex exists even in the dilute emitter with a sufficiently low concentration (0.5 wt %) in an inert host.
View Article and Find Full Text PDFResearch (Wash D C)
February 2020
Department of Chemistry, Sauvage Center for Molecular Sciences, Wuhan University, Wuhan 430072, China.
For the first time, electroplex emission is utilized to enhance the performance of nondoped blue organic light-emitting diodes (OLEDs). By decorating the twisted blue-emitting platform and adjusting the electronic structure, three molecules of 3Cz-Ph-CN, 3Cz-mPh-CN, and 3Ph-Cz-CN with a donor-acceptor structure are synthesized and investigated. When external voltage is applied, electroplex emission, which contributes to the emission performance of OLED, can be realized at the interface between the emitting layer and the electron-transporting layer.
View Article and Find Full Text PDFJ Am Chem Soc
April 2019
Photosciences and Photonics Section, Chemical Sciences and Technology Division , CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram 695019 , India.
Diels-Alder photocycloaddition of 9-phenylethynylanthracene results in multiple [4 + 2] and [4 + 4] cycloaddition products in solution, which can be controlled to form specific products under a restricted environment. We have exploited the gel phase of a 9-phenylethynylanthracence derivative as a confined medium to specifically yield the [4 + 2] cycloadduct in >90% yield. The photocycloadduct ( anti-form) exhibited a blue emission with CIE chromaticity of x = 0.
View Article and Find Full Text PDFAdv Sci (Weinh)
February 2018
Department of Chemistry Kangwon National University 1, Gangwondaehak-gil Chuncheon Gangwon 24341 South Korea.
A new concept of host, electroplex host, is developed for high efficiency and long lifetime phosphorescent organic light-emitting diodes by mixing two host materials generating an electroplex under an electric field. A carbazole-type host and a triazine-type host are selected as the host materials to form the electroplex host. The electroplex host is found to induce light emission through an energy transfer process rather than charge trapping, and universally improves the lifetime of red, yellow, green, and blue phosphorescent organic light-emitting diodes by more than four times.
View Article and Find Full Text PDFChemphyschem
April 2011
Department of Chemistry, University of Houston, Houston, TX 77204, USA.
The electroluminescent (EL) properties of a cross-linkable carbazole-terminated poly(benzyl ether) dendrimer, G(3)-cbz DN, doped into a PVK:PBD host matrix with a double-layer device configuration are investigated. Different concentrations of the guest material can control device efficiency, related to chromaticity of white emission and the origin of excited-state complexes occurring between hole-transporting carbazole units (PVK or G(3)-cbz DN) and electron-transporting oxadiazole (PBD). Two excited states (exciplex and electroplex) generated at the interfaces of PVK/G(3)-cbz DN and PBD result in competitive emission, exhibiting a broad band in the EL spectra.
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