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51.
Unprecedented Homoleptic Bis‐Tridentate Iridium(III) Phosphors: Facile,Scaled‐Up Production,and Superior Chemical Stability
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Jun Lin Yang Wang Premkumar Gnanasekaran Yu‐Cheng Chiang Chun‐Chieh Yang Chih‐Hao Chang Shih‐Hung Liu Gene‐Hsiang Lee Pi‐Tai Chou Yun Chi Shun‐Wei Liu 《Advanced functional materials》2017,27(35)
Bis‐tridentate Ir(III) metal complexes are expected to show great potential in organic light‐emitting diode (OLED) applications due to the anticipated, superb chemical and photochemical stability. Unfortunately, their exploitation has long been hampered by lack of adequate methodology and with inferior synthetic yields. This hurdle can be overcome by design of the first homoleptic, bis‐tridentate Ir(III) complex [Ir(pzpyph)(pzHpyph)] ( 1 ), for which the abbreviation (pzpyph)H (or pzHpyph) stands for the parent 2‐pyrazolyl‐6‐phenyl pyridine chelate. After that, methylation and double methylation of 1 afford the charge‐neutral Ir(III) complex [Ir(pzpyph)(pzMepyph)] ( 2 ) and cationic complex [Ir(pzMepyph)2][PF6] ( 3 ), while deprotonation of 1 gives formation of anionic [Ir(pzpyph)2][NBu4] ( 4 ), all in high yields. These bis‐tridentate Ir(III) complexes 2 – 4 are highly emitted in solution and solid states, while the charge‐neutral 2 and corresponding t ‐butyl substituted derivative [Ir(pzpyBuph)(pzMepyBuph)] ( 5 ) exhibit superior photostability versus the tris‐bidentate references [Ir(ppy)2(acac)] and [Ir(ppy)3] in toluene under argon, making them ideal OLED emitters. For the track record, phosphor 5 gives very small efficiency roll‐off and excellent overall efficiencies of 20.7%, 66.8 cd A?1, and 52.8 lm W?1 at high brightness of 1000 cd m?2. These results are expected to inspire further studies on the bis‐tridentate Ir(III) complexes, which are judged to be more stable than their tris‐bidentate counterparts from the entropic point of view. 相似文献
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53.
Magdalena Laskowska Anna Nowak Mateusz Dulski Peter Weigl Thomas Blochowicz ukasz Laskowski 《International journal of molecular sciences》2021,22(24)
Photoluminescence is known to have huge potential for applications in studying biological systems. In that respect, phosphorescent dye molecules open the possibility to study the local slow solvent dynamics close to hard and soft surfaces and interfaces using the triplet state (TSD: triplet state solvation dynamics). However, for that purpose, probe molecules with efficient phosphorescence features are required with a fixed location on the surface. In this article, a potential TSD probe is presented in the form of a nanocomposite: we synthesize spherical silica particles with 2-naphthalene methanol molecules attached to the surface with a predefined surface density. The synthesis procedure is described in detail, and the obtained materials are characterized employing transmission electron microscopy imaging, Raman, and X-ray photoelectron spectroscopy. Finally, TSD experiments are carried out in order to confirm the phosphorescence properties of the obtained materials and the route to develop phosphorescent sensors at silica surfaces based on the presented results is discussed. 相似文献
54.
New iridium complexes, [Ir(dpq)2(acac), Ir(PF-dpq)2(acac) and Ir(PF-dpq-5F)2(acac)] (dpq = 2,4-diphenylquinoline, dpq-5F = 2-(3′-fluorophenyl)-4-phenylquinoline), PF-dpq-5F = 2-(3-fluoro-phenyl)-6-pentafluorophenyl-4-phenylquinoline and acac = acetylacetonate) have been synthesized and characterized for efficient red organic light-emitting diodes (OLEDs). In order to improve the luminescence efficiency by preventing self-quenching and to tune photoluminescence (PL) and electroluminescence (EL) spectra to a longer wavelength, dpq ligand was fluorinated by -PF and -F moieties. However, the iridium complex of PF-dpq-5F underwent a weak MLCT transition because of the weak coupling between the 5d orbital of the iridium atom and HOMO of the substituted ligand. Thus, the maximum luminous efficiencies of the device using Ir(dpq)2(acac), Ir(PF-dpq)2(acac) and Ir(PF-dpq-5F)2(acac) are 4.36 cd/A, 6.04 cd/A and 4.35 cd/A, respectively. 相似文献
55.
Koren K Dmitriev RI Borisov SM Papkovsky DB Klimant I 《Chembiochem : a European journal of chemical biology》2012,13(8):1184-1190
Ir(III)-porphyrins are a relatively new group of phosphorescent dyes that have potential for oxygen sensing and labeling of biomolecules. The requirement of two axial ligands for the Ir(III) ion permits simple linkage of biomolecules by a one-step ligand-exchange reaction, for example, using precursor carbonyl chloride complexes and peptides containing histidine residue(s). Using this approach, we produced three complexes of Ir(III)-octaethylporphyrin with cell-penetrating (Ir1 and Ir2) and tumor-targeting (Ir3) peptides and studied their photophysical properties. All of the complexes were stable and possessed bright, long-decay (unquenched lifetimes exceeding 45 μs) phosphorescence at around 650 nm, with moderate sensitivity to oxygen. The Ir1 and Ir2 complexes showed positive staining of a number of mammalian cell types, thus demonstrating localization similar to endoplasmic reticulum and ATP- and temperature-independent intracellular accumulation (direct translocation mechanism). Their low photo- and cytotoxicity allows intracellular oxygen to be probed. 相似文献
56.
尝试将激光诱导磷光测温技术应用到发动机缸内气体的二维温度测量中。其原理是利用Dy:YAG磷光剂受355 nm波长的激光激发后辐射的磷光波长特性进行温度测量。标定了激光照射后两种磷光波长的强度比与温度的变化关系。实验测试得到了该发动机在不同曲轴转角下缸内燃烧气体的二维温度分布,画出了测试平面上温度分布的柱状图,并根据标准偏差分析了不同曲轴转角下的温度分布结果,分析了燃烧的进展情况,通过与燃料燃烧质量分数划分的燃烧阶段相比较,验证了激光诱导磷光测温技术在发动机缸内燃烧温度研究中的可行性。 相似文献
57.
Andreas Hohenleutner Susanna Schmidbauer Rudolf Vasold Dominik Joosten Philipp Stoessel Herwig Buchholz Burkhard König 《Advanced functional materials》2012,22(16):3406-3413
This work reports the combinatorial synthesis and screening of phosphorescent iridium complexes as solution processable emitters for OLEDs. The approach taken here allows for the rapid synthesis, isolation, spectroscopic characterization and identification of the libraries based on chromatographic methods. Subsequent analysis of the irradiation induced degradation provides insight on the stability of the complexes under continuous excitation. The method is versatile and can easily be applied to other metal complexes or organic dyes for various applications, e.g., in electroluminescence, photovoltaics and sensing. 相似文献
58.
A series of red-phosphorescent iridium (III) complexes 1-4 based on 5-benzoyl-2-phenylpyridine derivatives was synthesized. Their photophysical and electrophosphorescent properties were investigated. Multilayered OLEDs were fabricated with a device structure ITO/4,4′,4″-tris(N-(naphtalen-2-yl)-N-phenyl-amino)triphenylamine (60 nm)/4,4′-bis(N-naphtylphenylamino)biphenyl (20 nm)/Ir(III) complexes (8%) doped in 4,4′-N,N′-dicarbazolebiphenyl (30 nm)/2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (10 nm)/tris(8-hydroxyquinolinyl)aluminum(III) (20 nm)/Liq (2 nm)/Al (100 nm). All devices exhibited efficient red emissions. Among those, in a device containing iridium complex 1 dopant, the maximum luminance was 14200 cd/m2 at 14.0 V. Also, its luminous, power, and quantum efficiency were 10.40 cd/A, 3.44 lm/W and 9.21% at 20 mA/cm2, respectively. The peak wavelength of the electroluminescence was 607 nm, with CIE coordinates of (0.615, 0.383) at 12.0 V, and the device also showed a stable color chromaticity with various voltages. 相似文献
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