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911.
Jee Ho Park Young Bum Yoo Keun Ho Lee Sun Woong Han Won Jin Choi Hong Koo Baik 《Journal of Sol-Gel Science and Technology》2013,67(1):130-134
We investigated a role of acetic acid for solution processed gallium doped indium oxide thin film transistors (TFTs). By adding acetic acid in solution instead of commonly used ethanolamine, electrical performance of GIO TFTs is significantly enhanced. We demonstrated that acetic acid plays a role in enhancing crystallinity, lowering decomposition temperature and reducing hydroxyl groups in the film. The GIO TFTs formed from acetic acid added solution have mobility of 12.68 cm2 V?1 s?1, threshold voltage of ?7.4 V, on/off current ratio of 1.07 × 108 and subthreshold slope of 0.78 V/decade. 相似文献
912.
Yoo Jin Kim Seok Ju Hong Woo Seung Shin Yong Rok Kwon Seung Ho Lim Hae Chan Kim Jung Soo Kim Jin Woong Kim Dong Hyun Kim 《先进技术聚合物》2020,31(2):273-283
A superabsorbent polymer (SAP) is a special polymer material that can absorb up to 500 times its own weight of pure water, but has a problem that it does not biodegrade itself and cause environmental pollution. Therefore, we aim to prepare a biodegradable SAP by using biomass‐based IA. The SAP must be able to retain absorbed water and absorb water under a given pressure. We have carried out studies to improve the surface hardness of the SAP to enhance absorption of water under a given pressure by surface‐crosslinking. Four types of surface‐crosslinkers, ethylene glycol diglycidyl ether (EGDGE), ethylene carbonate (EC), 1,4‐butanediol (BD), or glycerol, were used. We confirmed the water absorption capacity of the SAP by measuring its centrifuge retention capacity (CRC) and absorbency under load (AUL). The structural characteristics of the SAP were confirmed by attenuated total reflection (ATR) and X‐ray photoelectron spectroscopy (XPS), and the surface characteristics were confirmed by scanning electron microscopy (SEM). 相似文献
913.
ABSTRACTNew supramolecular comblike polyimides with mesogenic side chains for stable homeotropic orientation and fast electro-optical switching of liquid crystals (LCs) have been prepared through selective intermolecular hydrogen bonding between 4-(4-heptylphenyl)benzoic acid (4HPB) and host polyimide. A low concentration of 4HPB as the mesogenic guest molecule was hydrogen-bonded to polyimide backbone leading to the self-assembled comblike polyimide with enhanced homeotropic orientation properties. The electro-optical characteristics of the LC device containing hydrogen-bonded comblike polyimide exhibited better performance than those of LC cell with conventional polyimide. Because the conventional covalent approach for preparation of polyimides requires considerable synthetic efforts to achieve new functionality in polyimide materials, the proposed noncovalent method is a simple one and highly cost effective. Our controlled methodology should find wide application for the fabrication of functional alignment materials requiring high orientation ability. 相似文献
914.
Yao Yuan Samira Adimi Xuyun Guo Tiju Thomas Ye Zhu Haichuan Guo G. Sudha Priyanga Pilsun Yoo Jiacheng Wang Jian Chen Peilin Liao J. Paul Attfield Minghui Yang 《Angewandte Chemie (International ed. in English)》2020,59(41):18036-18041
The oxygen evolution reaction (OER) is key to renewable energy technologies such as water electrolysis and metal–air batteries. However, the multiple steps associated with proton‐coupled electron transfer result in sluggish OER kinetics and catalysts are required. Here we demonstrate that a novel nitride, Ni2Mo3N, is a highly active OER catalyst that outperforms the benchmark material RuO2. Ni2Mo3N exhibits a current density of 10 mA cm?2 at a nominal overpotential of 270 mV in 0.1 m KOH with outstanding catalytic cyclability and durability. Structural characterization and computational studies reveal that the excellent activity stems from the formation of a surface‐oxide‐rich activation layer (SOAL). Secondary Mo atoms on the surface act as electron pumps that stabilize oxygen‐containing species and facilitate the continuity of the reactions. This discovery will stimulate the further development of ternary nitrides with oxide surface layers as efficient OER catalysts for electrochemical energy devices. 相似文献
915.
Dong-Joo Yoo Sungyun Yang Prof. Ki Jae Kim Prof. Jang Wook Choi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(35):14979-14986
In lithium metal batteries, electrolytes containing a high concentration of salts have demonstrated promising cyclability, but their practicality with respect to the cost of materials is yet to be proved. Here we report a fluorinated aromatic compound, namely 1,2-difluorobenzene, for use as a diluent solvent in the electrolyte to realize the “high-concentration effect”. The low energy level of the lowest unoccupied molecular orbital (LUMO), weak binding affinity for lithium ions, and high fluorine-donating power of 1,2-difluorobenzene jointly give rise to the high-concentration effect at a bulk salt concentration near 2 m , while modifying the composition of the solid-electrolyte-interphase (SEI) layer to be rich in lithium fluoride (LiF). The employment of triple salts to prevent corrosion of the aluminum current collector further improves cycling performance. This study offers a design principle for achieving a local high-concentration effect with reasonably low bulk concentrations of salts. 相似文献
916.
Palladium particles were simply synthesized using various ionic liquids. The morphology of the particles was significantly affected by the anion parts of the ionic liquids. Among the ionic liquids, hexafluorophosphate as an anion part was more effective in forming the palladium particles with relatively small and narrow size distribution. However, irregularly shaped palladium particles were synthesized without ionic liquid assistance. For a hexafluoropropylene hydrogenation to produce hydrofluorocarbons, palladium was impregnated on a carbon powder as a catalyst. During the preparation of the catalyst, ionic liquids were added to control the shape of the palladium on the support. After calcinations at 500 °C, all catalysts possessed the comparable crystal structure. Under identical reaction conditions, the catalyst prepared using 1-hexyl-3-methylimidazolium hexafluorophosphate was the most effective in this reaction. Hence, catalytic activity was mainly determined by the size of the palladium particles. 相似文献
917.
Dina V. Hingorani Dr. Byunghee Yoo Adam S. Bernstein Dr. Mark D. Pagel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9840-9850
This review focuses on exogenous magnetic resonance imaging (MRI) contrast agents that are responsive to enzyme activity. Enzymes can catalyze a change in water access, rotational tumbling time, the proximity of a 19F‐labeled ligand, the aggregation state, the proton chemical‐exchange rate between the agent and water, or the chemical shift of 19F, 31P, 13C or a labile 1H of an agent, all of which can be used to detect enzyme activity. The variety of agents attests to the creativity in developing enzyme‐responsive MRI contrast agents. 相似文献
918.
The FeCl3 · 6H2O/indium system efficiently causes debromination of various dibromides to the corresponding alkenes in good to excellent yields under mild conditions. 相似文献
919.
It has been found that dialkyl, diaryl, and aryl alkyl sulfoxides can be selectively converted to the corresponding sulfides with a NbCl5/In system in good to excellent yields under mild conditions. Several functional groups (bromo, chloro, methoxy, aldehyde, and vinyl) were tolerated under the reaction conditions. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
920.
Reverse Micelle Synthesis of Colloidal Nickel–Manganese Layered Double Hydroxide Nanosheets and Their Pseudocapacitive Properties
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Hwansu Sim Changshin Jo Prof. Taekyung Yu Eunho Lim Prof. Songhun Yoon Prof. Jung Heon Lee Prof. Jibeom Yoo Prof. Jinwoo Lee Prof. Byungkwon Lim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(45):14880-14884
Colloidal nanosheets of nickel–manganese layered double hydroxides (LDHs) have been synthesized in high yields through a facile reverse micelle method with xylene as an oil phase and oleylamine as a surfactant. Electron microscopy studies of the product revealed the formation of colloidal nanoplatelets with sizes of 50–150 nm, and X‐ray diffraction, energy dispersive X‐ray spectroscopy, and X‐ray photoelectron spectroscopy studies showed that the Ni–Mn LDH nanosheets had a hydrotalcite‐like structure with a formula of [Ni3Mn(OH)8](Cl?) ? n H2O. We found that the presence of both Ni and Mn precursors was required for the growth of Ni‐Mn LDH nanosheets. As pseudocapacitors, the Ni–Mn LDH nanosheets exhibited much higher specific capacitance than unitary nickel hydroxides and manganese oxides. 相似文献