China 
Africa 
Explore chapters and articles related to this topic
Recent Progress in the Development of Optoelectronic Materials Based on Group 13 Element-containing Conjugated Polymers
Published in John R. Reynolds, Barry C. Thompson, Terje A. Skotheim, Conjugated Polymers, 2019
Shunichiro Ito, Masayuki Gon, Kazuo Tanaka, Yoshiki Chujo
Coughlin, Carter, and coworkers synthesized o- or p-carborane-containing polyfluorenes by nickel-catalyzed Yamamoto coupling polymerization (Figure 12.10a) [115, 116]. The incorporation of o-carborane into polyfluorene gave rise to new lower energy emission in the solution fluorescence spectrum in the region of 565 nm, in addition to the blue emission from the fluorene unit. This behavior was probably derived from the main chain π-conjugation involving o-carborane moiety. Heeney and coworkers synthesized π-conjugated polymers containing benzocarborano[2,1-b:3,4-bʹ]bithiophene [112] and evaluated their charge-transporting behaviors (Figure 12.10b) [117]. The resulting polymers exhibited fully delocalized conjugated backbones and light absorption in the visible region. Importantly, pBZZT-DPP, as shown in Figure 12.10b, demonstrated ambipolar transistor performance in the top gated structures; hole and electron mobilities were determined to be 1 × 10–3 and 1 × 10–4 cm2 V–1 s–1, respectively. These continuous investigations have revealed that carboranes should be a versatile scaffold for constructing advanced optoelectronic materials.
Fabrication of (a-nc) boron carbide thin films via chemical vapor deposition using ortho-carborane
Published in Journal of Asian Ceramic Societies, 2020
Rong Tu, Xuan HU, Jun Li, Meijun Yang, Qizhong Li, Ji Shi, Haiwen Li, Hitoshi Ohmori, Takashi Goto, Song Zhang
Of the many types of CVD processes, plasma-enhanced chemical vapor deposition (PECVD) has been extensively used to fabricate boron carbide films because high internal energy state of plasma enhances the chemical reaction rate of the precursor. However, this plasma process could cause damage to the surface of the substrate due to the energetic ions. Thermal chemical vapor deposition technique, in some cases, is even better than PECVD processes due to its design simplicity, lower ownership cost and better control of deposition process. However, thermal CVD using ortho-carborane to prepare boron carbide films was not widely adopted or studied. In addition, most of the boron carbide films prepared by CVD reported were amorphous, and there were few reports of nanocrystalline boron carbide films.
Synthesis and characterization of Cp*Ir-dithiolene-o-carborane phosphine complexes: A continuous investigation of B−H⋯π interaction
Published in Molecular Physics, 2019
Hou-ji Cao, Huimin Dai, Xiaolei Zhang, Hong Yan, Changsheng Lu
B−H⋯π interactions have been experimentally observed at room temperature in the template of [Ir(PR3)(S2C2B10H10)] (R=C6H4X, X=H, F, OMe) [14]. However, the utilisation of sterically crowding triphenylphosphine ligands excludes the entropic factors since one of the B−H bonds of the carborane is positioned above the phenyl ring to form B−H⋯π hydrogen bond. In addition, theoretical calculations on the B2H6⋯benzene system indicated that non-covalent B−H⋯π interactions could only be observed at low temperatures because of an entropy penalty at room temperature (298 K) [23]. Herein, sterically less crowding phosphine ligand was chosen in the newly designed templates B1, C1, B2, C2 and NMR technique was utilised for the detection of B−H⋯π interactions at low temperatures. All B−H and C−H distances of the carborane clusters referred to below were set to 1.10 Å.
Plasma Confinement in the L-2M Stellarator at High Microwave Heating Powers
Published in Fusion Science and Technology, 2023
Dmitriy Vasilkov, Stanislav Grebenshchikov, Irina Grishina, Vyacheslav Ivanov, Nikolay Kharchev, Alexey Meshcheryakov, Vladimir Stepakhin
It is possible to estimate the maximum energy input using the following parameters. At an average density of ne ~ 1.5 × 1019 m−3 in the plasma volume V = 0.25 m3, in previously conducted experiments the specific energy input (power per particle) varied in the range Ppart = 0.15 to 0.7 × 10−13 W/particle; the threshold power for the appearance of transition processes is 0.4 × 10−13 W/particle. The heat load onto the vacuum chamber wall correlates with the heating power. It is estimated that for the ECRH power of 200 kW, the load onto the chamber wall is 0.5 MW/m2 near the separatrix X-points (that is, the points closest to the chamber walls, located at a distance of approximately 0.5 to 1 cm from it). At the same time, the region of the highest heat loads (which is approximately 50% of the total heat load) consists of two helical tracks with seven turns around the chamber axis with a total area of ~0.3 m2. Near the separatrix X-points, the plasma flow interacts with the wall and causes sputtering of the material coating the wall (carborane and hydrogen absorbed by it), as a result of which the traces are formed on the vacuum chamber wall (Fig. 4). The thermal effect is exerted on the wall of the vacuum chamber during experiments with a pulse duration up to 20 ms with a repeatability of 10 pulses/h. The formation of a screw trace is also associated with the oxidation of the wall material and possibly with the formation of unipolar microarcs. Heat loads cause sputtering of the material coating the wall (carborane and hydrogen absorbed by it) and cause pulsed injection of atoms of the coating material into the wall plasma. Unfortunately, a detailed analysis of material damage on microscopes has not been carried out; it is expected in the future.