36602-01-4Relevant articles and documents
High-efficiency exciplex-based white organic light-emitting diodes with a new tripodal material as a co-host
Zhang, Yuan-Lan,Ran, Quan,Wang, Qiang,Fan, Jian,Liao, Liang-Sheng
, p. 7267 - 7272 (2019)
Exciplex-forming co-hosts have been reported to be a potentially suitable material for organic light-emitting diodes (OLEDs). However, they might not be able to provide optimal low voltage and maximal power efficiency (PE), when used in white organic light-emitting diodes (WOLEDs). Herein, a novel strategy using multi-exciplex-forming co-hosts (MEHs) is introduced to achieve enhanced efficiency and low operating voltage. To realize this strategy, a new tripodal bipolar compound CNTPA-DPA was synthesized and used as a co-host in the devices. As a result, the orange light-emitting component in WOLEDs provides 27% external quantum efficiency (EQE), 2.1 V turn-on voltage, and 115.5 lm W-1 PE, which are among the best values of orange color emission in OLEDs. And then this orange light emitting component was adopted in the MEH strategy to construct WOLEDs, achieving 19.5% EQE and 73 lm W-1 PE at the maximum, which are 45.7% and 19.6% higher than those using a single exciplex as the host, respectively. Moreover, the well-matched energy alignment endows the device with a very low operating voltage of 3.8 V at 1000 cd m-2. These results indicate that the performance of the exciplex-based WOLEDs can be remarkably enhanced by using the MEH strategy.
Meta conjugation effect on the torsional motion of aminostilbenes in the photoinduced intramolecular charge-transfer state
Yang, Jye-Shane,Liau, Kang-Ling,Li, Chun-Yi,Chen, Mon-Yao
, p. 13183 - 13192 (2007)
The photochemical behavior of a series of trans-3-(N-arylamino)stilbenes (m1, aryl = 4-substituted phenyl with a substituent of cyano (CN), hydrogen (H), methyl (Me), or methoxy (OM)) in both nonpolar and polar solvents is reported and compared to that of the corresponding para isomers (p1CN, p1H, p1Me, and p10M). The distinct propensity of torsional motion toward a low-lying twisted intramolecular charge-transfer (TICT) state from the planar ICT (PICT) precursor between the meta and para isomers of 1CN and 1Me reveals the intriguing meta conjugation effect and the importance of the reaction kinetics. Whereas the poor charge-redistribution (delocalization) ability through the meta-phenylene bridge accounts for the unfavorable TICT-forming process for m1CN, it is such a property that slows down the decay processes of fluorescence and photoisomerization for m1Me, facilitating the competition of the single-bond torsional reaction. In contrast, the quinoidal character for p1Me in the PICT state kinetically favors both fluorescence and photoisomerization but disfavors the single-bond torsion. The resulting concept of thermodynamically allowed but kinetically inhibited TICT formation could also apply to understanding the other D-A systems, including trans-4-cyano-4′-(N,N-dimethylamino)stilbene (DCS) and 3-(N,N-dimethylamino)benzonitrile (3DMABN).
Red electroluminescent compound as well as preparation method and application thereof
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Paragraph 0047; 0048; 0049; 0050, (2021/04/28)
The invention discloses a red electroluminescent compound as well as a preparation method and application thereof, belonging to the technical field of organic photoelectricity. The red electroluminescent compound has a chemical structural formula shown in the specification. The red electroluminescent compound has the advantages of cheap monomer raw materials, simple synthesis route, convenient purification, convenience in research on a structure-performance relationship, and easiness in industrial scale-up production. The red electroluminescent compound disclosed by the invention is simple in synthetic route, convenient to purify, novel in structure and good in electroluminescent property; the compound has good solubility and can be used for preparing a large-area flexible display device by adopting a solution processing technology; and the compound has huge development potential and prospects in the field of organic electronic display.
Schiff bases-titanium (III) & (IV) complex compounds: Novel photocatalysts in Buchwald-Hartwig C–N cross-coupling reaction
Absalan, Yahya,Ghandi, Khashayar,Gholizadeh, Mostafa,Kovalchukova, Olga,Mahmoudi, Ghodrat,Sarvestani, Hossein Sabet,Shad, Nazanin Noroozi,Strashnov, Pavel
, (2021/05/21)
Nine novel Schiff bases were derived from salicylic aldehyde and oxalic aldehyde, isolated, and their molecular and spatial structure were explored by a set of experiments (IR, CNMR, HNMR, CHN, SEM, XRD) and theoretical simulation (DFT def2-TZVP). A high potential was predicted in metal cations chelating. The isolated organic species were applied as the ligands in the reaction of complex formation with titanium (III) chloride and (IV) bromide and 12 novel complexes were synthesized and studied experimentally and theoretically. Using the UV–vis spectroscopic titration, the solution stability of the complexes was indicated. Depending on the nature of the Schiff base ligand, their formation constants were calculated in the range of 6.84–17.32. Using the DFT def2-TZVP theoretical method together with the experimental spectroscopic data, the coordination types of the ligands were investigated, and the structure of the complexes was proposed. The photocatalytic ability of the isolated complexes was tested in the C-N cross-coupling reaction under sunlight. Complexes exhibited high visible-light photocatalytic activity for a wide range of aromatic and benzylic amines including electron-withdrawing and electron-donating groups from moderate to good yields ranging in 50–85 %. The use of an inexpensive, clean, and renewable energy source (visible light) is the superiority of the developed photocatalytic systems.
