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Takashi Ito Prof. Hisahiro Sasabe Dr. Yuji Nagai Dr. Yuichiro Watanabe Natsuki Onuma Prof. Junji Kido 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(30):7308-7314
Deep-red to near-infrared (NIR) OLEDs, which yield emission peak wavelengths beyond λ=660 nm, are applicable as unique light sources in plant growth or health monitoring systems. Compared with other visible-spectrum OLEDs, however, research in the field of deep-red OLEDs is not as advanced. In this work, three new types of dibenzofuran-based host materials are developed as n-type exciplex host partners. Combining these with the deep-red iridium complex bis(2,3-diphenylquinoxaline)iridium(dipivaloylmethane) ([(DPQ)2Ir(dpm)]) and N,N′-di(naphalene-1-yl)-N,N′-diphenylbenzidine (α-NPD) as a p-type exciplex host partner, a highly efficient deep-red OLED can be realized with a maximum external quantum efficiency (ηext,max) of over 16 % with Comission Internationale de l′Éclairge (CIE) coordinates of (0.71, 0.28). In addition, the effect of the doping concentration and the p/n ratio of the exciplex host on the efficiency and the lifetime of the OLEDs are investigated. Consequently, the optimized device exhibits a ηext,max of over 15 % and a six-time longer lifetime operating at high brightness of 100 cd m−2 compared with other state-of-the-art deep-red OLEDs. 相似文献
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Hiroshi Akutsu Kosuke Nakashima Shin-ichi Hirashima Hikari Matsumoto Yuji Koseki Tsuyoshi Miura 《Tetrahedron》2019,75(16):2431-2435
The asymmetric direct bisvinylogous conjugate addition of 5-benzylfurfural derivatives to nitroalkenes using a thiourea organocatalyst resulted in a corresponding ε-regioselective addition products in high yields and up to 95% enantiomeric excess. 相似文献
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Optical Review - Plasmonic nanostructures or metasurfaces have recently been actively researched for structural color generation. Controlling the plasmonic resonant wavelengths of surface plasmon... 相似文献
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The absorption states of hydrogen isotopes in various ceramic materials were investigated by density functional theory. For pristine ceramic materials, main-group oxides do not form any bond with a hydrogen atom. However, transition metal oxides form hydroxyl groups and absorb hydrogen atoms. Main-group and transition metal nitrides form ionic bonds between a hydrogen atom and the surrounded cation. For anion-deficient ceramic materials, hydrogen atoms are negatively charged because of excess electrons induced by anion vacancies, and ionic bonds form with the surrounded cation, which stabilizes the hydrogen absorption state. N substitutional doping into oxides introduces an electron hole, while O substitutional doping into the nitrides introduces an excess of electrons. Therefore, hydrogen isotopes form covalent bonds in N-substituted oxides, and form hydride ions in O-substituted nitrides. Thus, Al2O3, SiO2, CrN, and TiN are promising materials as hydrogen permeation barriers. 相似文献
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Periodica Mathematica Hungarica - We completely classify continuous fractional operations on the complex number field $$\mathbb {C}$$ modulo equivalence. A continuous fraction is described by a... 相似文献