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41.
42.
Xiaopei Li Tasuku Ogihara Prof. Dr. Manabu Abe Dr. Yasuyuki Nakamura Prof. Dr. Shigeru Yamago 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9846-9850
The effect of viscosity on the diffusion efficiency (Fdif) of an organic radical pair in a solvent cage and the termination mechanism, that is, the selectivity of disproportionation (Disp) and combination (Comb) of the geminated caged radical pair and the diffused radicals encountered, were investigated quantitatively by following the photolysis of dimethyl 2,2′-azobis(2-methylpropionate) (V-601) in the absence and presence of PhSD. Fdif and Disp/Comb selectivity outside the cage [Disp(dif)/Comb(dif)] are highly sensitive to the viscosity. In contrast, the Disp/Comb selectivity inside the cage [Disp(cage)/Comb(cage)] is rather insensitive. The difference in viscosity dependence between Disp(cage)/Comb(cage) and Disp(dif)/Comb(dif) is explained by the spin state of the radical pair inside and outside the cage and the spin state dependent configurational changes of the radical pair upon their collision. Given that the configurational change of the radicals associates the displacement and reorganization of solvents around the radicals, the termination outside the cage, which requires larger change than that inside the cage, is highly viscosity dependent. Furthermore, while the bulk viscosity of each solvent shows good correlation with Fdif and Disp/Comb selectivity, microviscosity is the better parameter predicting Fdif and Disp(dif)/Comb(dif) selectivity regardless of the solvents. 相似文献
43.
Nathamgari S. S. P. Dong S. Hosseinian E. Lauhon L. J. Espinosa H. D. 《Experimental Mechanics》2019,59(3):349-359
Experimental Mechanics - Nanoelectromechanical (NEMS) systems fabricated using atomically thin materials have low mass and high stiffness and are thus ideal candidates for force and mass sensing... 相似文献
44.
Dr. Huiliang Sun Dr. Lei Wang Dr. Yingfeng Wang Prof. Xugang Guo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(1):87-105
Imide-functionalized π-conjugated polymer semiconductors have received a great deal of interest owing to their unique physicochemical properties and optoelectronic characteristics, including excellent solubility, highly planar backbones, widely tunable band gaps and energy levels of frontier molecular orbitals, and good film morphology. The organic electronics community has witnessed rapid expansion of the materials library and remarkable improvement in device performance recently. This review summarizes the development of imide-functionalized polymer semiconductors as well as their device performance in organic thin-film transistors and polymer solar cells, mainly achieved in the past three years. The materials mainly cover naphthalene diimide, perylene diimide, and bithiophene imide, and other imide-based polymer semiconductors are also discussed. The perspective offers our insights for developing new imide-functionalized building blocks and polymer semiconductors with optimized optoelectronic properties. We hope that this review will generate more research interest in the community to realize further improved device performance by developing new imide-functionalized polymer semiconductors. 相似文献
45.
Ling-Yang Hsu Qiumin Liang Zhiheng Wang Hsin-Hung Kuo Wun-Shan Tai Shi-Jian Su Xiuwen Zhou Yi Yuan Yun Chi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(67):15375-15386
Iridium complexes bearing chelating cyclometalates are popular choices as dopant emitters in the fabrication of organic light-emitting diodes (OLEDs). In this contribution, we report a series of blue-emitting, bis-tridentate IrIII complexes bearing chelates with two fused five-six-membered metallacycles, which are in sharp contrast to the traditional designs of tridentate chelates that form the alternative, fused five-five metallacycles. Five IrIII complexes, Px-21 – 23 , Cz-4 , and Cz-5 , have been synthesized that contain a coordinated dicarbene pincer chelate incorporating a methylene spacer and a dianionic chromophoric chelate possessing either a phenoxy or carbazolyl appendage to tune the coordination arrangement. All these tridentate chelates afford peripheral ligand–metal–ligand bite angles of 166–170°, which are larger than the typical bite angle of 153–155° observed for their five-five-coordinated tridentate counterparts, thereby leading to reduced geometrical distortion in the octahedral frameworks. Photophysical measurements and TD-DFT studies verified the inherent transition characteristics that give rise to high emission efficiency, and photodegradation experiments confirmed the improved stability in comparison with the benchmark fac-[Ir(ppy)3] in degassed toluene at room temperature. Phosphorescent OLED devices were also fabricated, among which the carbazolyl-functionalized emitter Cz-5 exhibited the best performance among all the studied bis-tridentate phosphors, showing a maximum external quantum efficiency (EQEmax) of 18.7 % and CIEx,y coordinates of (0.145, 0.218), with a slightly reduced EQE of 13.7 % at 100 cd m−2 due to efficiency roll-off. 相似文献
46.
A series of 3-perfluoroalkylbenzoate esters are synthesised. They tend to exhibit enantiotropic SmA and SmC phases. The clearing points are decreased with increasing the alkoxy chain length and show odd-even effect. With increasing the fluorocarbon chain length, the melting and clearing points increase; however, the SmC phase is suppressed. 相似文献
47.
Coordinate Bond Breaking Induced by Collapse of Poly(\begin{document}$N$\end{document} -isopropyl acrylamide) as Ligands of a Rare Earth Complex 下载免费PDF全文
A novel water-soluble luminescent complex consisting of Eu(ally-dbm)\begin{document}$_3$\end{document} -2Tppo and poly(N-isopropyl acrylamide) (PNIPAM) is synthesized through a series of chemical reactions. The structure of the complex is characterized by TGA, GPC, HNMR, and the thermal-responsive fluorescence of the complex in aqueous solution is investigated. It is found that PNIPAM collapse above the lower critical solution temperature causes the coordination bond breaking, leading to weakening of the fluorescence from Eu\begin{document}$^{3+}$\end{document} and enhancing of the fluorescence from the ligands. When temperature decreases, the fluorescence from Eu\begin{document}$^{3+}$\end{document} is found to boost up and the fluorescence from ligands weakens accordingly. It is deduced from this phenomenon that the ligands re-coordinate with europium ions again along with the temperature decreasing, which is further confirmed by IR measurements. This thermal-responsive fluorescence is of reversibility, which can be used as molecular probes for biological imaging and collapse studying of PNIPAM. 相似文献
48.
Various types of data become available at different stages of a reservoir’s life. The production data are integrated into the flow simulation models through a process referred to as history matching. The history-matching process is iterative, and it usually involves a large number of simulation runs. Hence, this process requires significant computational time. In most history-matching methods, the initial geological assumptions in the reservoir model are destroyed or significantly altered in the process. Furthermore, they do not account for the information obtained during the previous trials, and lack learning from the previous failures. In this paper, we introduce a new methodology that maintains the geological realism. The candidate realizations are selected through a learning-based history-matching (LHM) algorithm by which all the previously successful patterns are preserved and used to assist the construction of the next realizations. The various pieces of matching regions are assembled together to make a pool of the successful candidates. Such regions are then utilized for making an auxiliary dataset in a multiscale framework by which the next model is generated. To prevent from trapping in local minima, ideas from the genetic algorithm is adapted. The LHM algorithm can be applied to both categorical and continuous distributions. The LHM provides a conditional map by which the new production data are immediately incorporated into the existing reservoir models. We apply the LHM algorithm to various 2D and 3D examples with very complex binary and continuous properties. The algorithm is shown to produce history-matched models with significantly smaller CPU times. 相似文献
49.
50.
Piezoelectric materials have received much attention due to their great potential in environmental remediation by utilizing vibrational energy. In this paper, a novel piezoelectric catalyst, CoOx nanoparticles anchored BiFeO3 nanodisk composite, was intentionally synthesized via a photodeposition method and applied in piezocatalytic degradation of rhodamine B (RhB) under ultrasonic vibration. The as-synthesized CoOx/BiFeO3 composite presents high piezocatalytic efficiency and stability. The RhB degradation rate is determined to be 1.29 h−1, which is 2.38 folds higher than that of pure BiFeO3. Via optimizing the reaction conditions, the piezocatalytic degradation rate of the CoOx/BiFeO3 can be further increased to 3.20 h−1. A thorough characterization was implemented to investigate the structure, piezoelectric property, and charge separation efficiency of the CoOx/BiFeO3 to reveal the nature behind the high piezocatalytic activity. It is found that the CoOx nanoparticles are tightly adhered and uniformly dispersed on the surface of the BiFeO3 nanodisks. Strong interaction between CoOx and BiFeO3 triggers the formation of a heterojunction structure, which further induces the migration of the piezoinduced holes on the BiFeO3 to CoOx nanoparticles. The recombination of electron-hole pairs is retarded, thereby increasing the piezocatalytic performance greatly. This work may offer a new paradigm for the design of high-efficiency piezoelectric catalysts. 相似文献