scholarly journals Probing Electron Excitation Characters of Carboline-Based Bis-Tridentate Ir(III) Complexes

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6048
Author(s):  
Jie Yan ◽  
Ze-Lin Zhu ◽  
Chun-Sing Lee ◽  
Shih-Hung Liu ◽  
Pi-Tai Chou ◽  
...  

In this work, we report a series of bis-tridentate Ir(III) metal complexes, comprising a dianionic pyrazole-pyridine-phenyl tridentate chelate and a monoanionic chelate bearing a peripheral carbene and carboline coordination fragment that is linked to the central phenyl group. All these Ir(III) complexes were synthesized with an efficient one-pot and two-step method, and their emission hue was fine-tuned by variation of the substituent at the central coordination entity (i.e., pyridinyl and phenyl group) of each of the tridentate chelates. Their photophysical and electrochemical properties, thermal stabilities and electroluminescence performances are examined and discussed comprehensively. The doped devices based on [Ir(cbF)(phyz1)] (Cb1) and [Ir(cbB)(phyz1)] (Cb4) give a maximum external quantum efficiency (current efficiency) of 16.6% (55.2 cd/A) and 13.9% (43.8 cd/A), respectively. The relatively high electroluminescence efficiencies indicate that bis-tridentate Ir(III) complexes are promising candidates for OLED applications.

RSC Advances ◽  
2020 ◽  
Vol 10 (58) ◽  
pp. 35206-35213
Author(s):  
Abdelaziz M. Aboraia ◽  
Viktor V. Shapovalov ◽  
Alexnader A. Guda ◽  
Vera V. Butova ◽  
Alexander Soldatov

LiCoPO4 (LCP) is a promising high voltage cathode material but suffers from low conductivity and poor electrochemical properties.


Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3918
Author(s):  
Anna Dymerska ◽  
Wojciech Kukułka ◽  
Marcin Biegun ◽  
Ewa Mijowska

The renewable energy technologies require electrocatalysts for reactions, such as the oxygen and/or hydrogen evolution reaction (OER/HER). They are complex electrochemical reactions that take place through the direct transfer of electrons. However, mostly they have high over-potentials and slow kinetics, that is why they require electrocatalysts to lower the over-potential of the reactions and enhance the reaction rate. The commercially used catalysts (e.g., ruthenium nanoparticles—Ru, iridium nanoparticles—Ir, and their oxides: RuO2, IrO2, platinum—Pt) contain metals that have poor stability, and are not economically worthwhile for widespread application. Here, we propose the spinel structure of nickel-cobalt oxide (NiCo2O4) fabricated to serve as electrocatalyst for OER. These structures were obtained by a facile two-step method: (1) One-pot solvothermal reaction and subsequently (2) pyrolysis or carbonization, respectively. This material exhibits novel rod-like morphology formed by tiny spheres. The presence of transition metal particles such as Co and Ni due to their conductivity and electron configurations provides a great number of active sites, which brings superior electrochemical performance in oxygen evolution and good stability in long-term tests. Therefore, it is believed that we propose interesting low-cost material that can act as a super stable catalyst in OER.


RSC Advances ◽  
2021 ◽  
Vol 11 (18) ◽  
pp. 11004-11010
Author(s):  
Zequn Ma ◽  
Chaojun Jing ◽  
Deyu Hang ◽  
Hongtao Fan ◽  
Lumeng Duan ◽  
...  

Three high-efficient green light iridium complexes were designed and prepared. Thermal stabilities, electrochemical properties, electroluminescence performances and substituents effects are presented and discussed in this study.


RSC Advances ◽  
2021 ◽  
Vol 11 (34) ◽  
pp. 20670-20678
Author(s):  
Zhen Shi ◽  
Yazhen Wang ◽  
Shaobo Dong ◽  
Tianyu Lan

Roadmap for the synthesis of Fe3O4–PVA@SH using the step-by-step method and one-pot method.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4615
Author(s):  
Dovydas Blazevicius ◽  
Daiva Tavgeniene ◽  
Simona Sutkuviene ◽  
Ernestas Zaleckas ◽  
Ming-Ruei Jiang ◽  
...  

Pyridinyl-carbazole fragments containing low molar mass compounds as host derivatives H1 and H2 were synthesized, investigated, and used for the preparation of electro-phosphorescent organic light-emitting devices (PhOLEDs). The materials demonstrated high stability against thermal decomposition with the decomposition temperatures of 361–386 °C and were suitable for the preparation of thin amorphous and homogeneous layers with very high values of glass transition temperatures of 127–139 °C. It was determined that triplet energy values of the derivatives are, correspondingly, 2.82 eV for the derivative H1 and 2.81 eV for the host H2. The new derivatives were tested as hosts of emitting layers in blue, as well as in green phosphorescent OLEDs. The blue device with 15 wt.% of the iridium(III)[bis(4,6-difluorophenyl)-pyridinato-N,C2′]picolinate (FIrpic) emitter doping ratio in host material H2 exhibited the best overall characteristics with a power efficiency of 24.9 lm/W, a current efficiency of 23.9 cd/A, and high value of 10.3% of external quantum efficiency at 100 cd/m2. The most efficient green PhOLED with 10 wt% of Ir(ppy)3 {tris(2-phenylpyridine)iridium(III)} in the H2 host showed a power efficiency of 34.1 lm/W, current efficiency of 33.9 cd/A, and a high value of 9.4% for external quantum efficiency at a high brightness of 1000 cd/m2, which is required for lighting applications. These characteristics were obtained in non-optimized PhOLEDs under an ordinary laboratory atmosphere and could be improved in the optimization process. The results demonstrate that some of the new host materials are very promising components for the development of efficient phosphorescent devices.


2011 ◽  
Vol 8 (3) ◽  
pp. 188-192 ◽  
Author(s):  
Zheng-Jun Quan ◽  
Rong-Guo Ren ◽  
Yu-Xia Da ◽  
Zhang Zhang ◽  
Xi-Cun Wang

2017 ◽  
Vol 46 (3) ◽  
pp. 865-874 ◽  
Author(s):  
Li-Yi Zhang ◽  
Liang-Jin Xu ◽  
Jin-Yun Wang ◽  
Xian-Chong Zeng ◽  
Zhong-Ning Chen

Cationic PtAu2 heterometallic complexes are used as phosphorescent emitters for highly efficient electroluminescent OLEDs through a solution process with the highest current efficiency of 51.7 cd A−1 and external quantum efficiency of 14.5%.


2018 ◽  
Vol 47 (22) ◽  
pp. 7587-7593 ◽  
Author(s):  
Ning Su ◽  
Zheng-Guang Wu ◽  
You-Xuan Zheng

Two efficient bluish green iridium(iii) complexes were applied as emitters in the organic light-emitting diodes, which showing high current efficiency of 58.17 cd A−1 and external quantum efficiency of 25.33% with low efficiency roll-off.


Synthesis ◽  
2020 ◽  
Author(s):  
Zbigniew Wróbel ◽  
Michał Tryniszewski ◽  
Robert Bujok ◽  
Roman Gańczarczyk

Tributyl- or triphenylphosphine promotes a one-pot, three-step method for the synthesis of differently substituted dibenzodiazepinones from N-aryl-2-nitroanilines. Pyridine analogues and the corresponding thiazepinones can also be formed using this method. The process involves deoxygenation of the nitro group, then formation of an iminophosphorane intermediate and its intramolecular condensation with a carboxyl group placed in the N-aryl group. The role of the carboxyl group in the formation of the iminophosphorane and the mode of cyclization are discussed.


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