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991.
992.
采用不同材料作为有机电致发光器件(OELDs)的电极, 制备了基本结构为[阳极/NPB(40 nm)]/Alq3(50 nm)/阴极]的异质结双层器件, 并通过改变OELDs器件的阴极或阳极来研究电极材料对器件光电性能的影响. 研究结果表明, 各器件电流-电压(I-V)关系的基本特征与陷阱电荷限制电流(TCLC)机制的拟合情况相符. 由于有机材料本身能级的无序性以及载流子迁移率对温度和电场的依赖性, 不同电极的载流子注入能力与其功函数并无直接关系. 双层器件中由于空穴传输层的引入, 使得载流子复合区域位于有机层异质结界面处, 降低了金属阴极对激子的猝灭作用, 从而大大提高了器件性能. 此外, 金属电极OLEDs器件结构具有的微腔效应会导致发射光谱的位移和谱峰宽度变窄, 这表明通过对金属电极的表面改性和优化可使器件性能超过常规结构的器件. 相似文献
993.
994.
Effects of process parameters on diamond film synthesis in DC thermal plasma jet reactors are discussed including substrate material, methane concentration and substrate temperature. Diamond has been deposited on silicon, molybdenum, tungsten, tantalum, copper, nickel, titanium, and stainless steel. The adhesion of diamond film to the substrate is greatly affected by the type of substrate used. It has been found that the methane concentration strongly affects the grain size of the diamond films. Increased methane concentrations result in smaller grain sizes due to the increased number of secondary nucleations on the existing facets of diamond crystals. Substrate temperature has a strong effect on the morphology of diamond films. With increasing substrate temperature, the predominant orientation of the crystal growth planes changes from the (111) to the (100) planes. Studies of the variation of the film quality across the substrate due to the nonuniformity of thermal plasma jets indicate that microcrystalline graphite formation starts at the corners and edges of diamond crystals when the conditions become unfavorable for diamond deposition. 相似文献
995.
Masahiko Imai Lu Gong Xu Kazuo Ametani Mituaki Tutiya 《Journal of polymer science. Part A, Polymer chemistry》1989,27(5):1763-1773
Polypropylene films were irradiated with 60Co γ-rays in vacuum or in air and stored in air. Just after irradiation, the concentration of carbonyl group of the sample irradiated in air only increased with dose. The concentrations of both samples increased with storage time. The more the absorbed doses, the higher the increasing rates. The increasing rate of the concentration of carbonyl group during irradiation in air was higher than those during storage in air. Just after irradiation, the tensile strengths and the elongations of the both samples somewhat increased with dose at the doses less than 5 Mrad, but decreased at doses more than 13 Mrad. The tensile strength and the elongation of the sample irradiated in air decreased with storage time. Those of the sample irradiated in vacuum also decreased with storage time but the decreasing rates were much smaller than those in the sample irradiated in air. The gel fractions of the samples irradiated in vacuum and annealed in vacuum were somewhat higher than those irradiated in vacuum and not annealed. To elucidate high oxidation rate in the sample irradiated in air during and after irradiation, reaction mechanisms were discussed. To clarify the difference of mechanical properties between the samples irradiated in vacuum and in air, the effect of crosslink was considered, together with the oxidation. 相似文献
996.
He X Pu W Han J Chen J Lu J Jiang C Wan C 《The journal of physical chemistry. B》2005,109(49):23141-23144
A method is proposed based on mode coupling theory in which the ion transference number is introduced into the theory. The ionic limiting molar conductivities of LiPF6, LiClO4, LiBF4, LiCF3SO3, Li(CF3SO3)2N, LiC4F9SO3, and LiAsF6 in PC(propylene carbonate), GBL(gamma-butyrolactone), PC(propylene carbonate)/EMC(ethylmethyl carbonate), and PC(propylene carbonate)/DME(dimethoxyethane) are calculated based on this method, which does not involve any adjustable parameter. The results fit well to the literature data which are calculated by an empirically adjusted formula. This presents a potential way to calculate the conductivities of Li-ion battery electrolytes. 相似文献
997.
Peng Lu Xueli Hu Yujie Li Yazhou Peng Meng Zhang Xue Jiang Youzhou He Min Fu Fan Dong Zhi Zhang 《Journal of Saudi Chemical Society》2019,23(8):1109-1118
A novel CaCO3/graphitic carbon nitride (g-C3N4) photocatalyst was synthesized for the first time via a facile calcination method using CaCO3 and melamine as precursors. The as-prepared samples were characterized using various techniques, such as scanning and transmission electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller analysis, as well as Fourier-transform infrared, X-ray photoelectron, photoluminescence, and UV–vis diffuse reflectance spectroscopy. The results of the experiments confirm the successful coupling of CaCO3 to g-C3N4. The photocatalytic activity of the synthesized CaCO3/g-C3N4 composites was evaluated by assessing their performance in the photocatalytic degradation of crystal violet (CV) in water under visible light irradiation. The analysis shows that CaCO3/g-C3N4 exhibits higher photocatalytic activity towards CV degradation (76.0%) than pristine g-C3N4 (21.6%) and CaCO3 (23.2%). Radical trapping and electron spin resonance experiments show that hydroxyl radicals (OH) and holes (h+) are the key reactive species in the photocatalytic process. The enhanced photocatalytic activity of the composite is mainly attributed to the efficient separation rate of electron-hole pairs achieved through the incorporation of CaCO3. 相似文献
998.
Synthesis of the third-order nonlinear materials:bis (1,4-dihydroxynaphthalene) tetrathiafulvalene and bis (1,4-dialkoxylnaphthalene) tetrathiafulvalene has been achieved in four steps, starting from 2,3-dichloro-1,4-naphthaquinone. The materials exhibit larger third-order nonlinear optical susceptibilities χ. 相似文献
999.
合成了Nd(ClO_4)_3·4phP=O·C_2H_5OH配合物,用四园衍射仪测定了它的分子及晶体结构,此晶体属三斜晶系P1空间群,晶胞参数为:a=13.475(61)A;b=15.003(15)A;c=18.697(15)A;α=85.44(7);β=78.49(24)°;γ=83.13(26)°;V=3671.2A,分子由99个非氢原子组成,实际上分子可分为三个部分即:配阳离子[Nd(ClO_4)_2·4phPO]~+;阴离子ClO_4和溶剂合分子C_2H_5OH配阳离子的钕与八个氧配位,四个氧来自双齿配位的ClO_4,四个氧来自四个ph_3PO,八个配位氧组成三角十二面体。 中性膦(磷)类化合物包括(RO)_3P=O和R_3P=O是一类重要的萃取剂。工业上已应用的TBP和TOPO都属于这一类。为了研究这类萃取剂在不同底液中萃取行为之所以不同的内在因素,我们制备了不同希土盐类与三苯基氧膦的配合物,并对它们进行了结构测定。已知的中性氧膦希土配合物中进行过结构测定的有Ce(NO)·2phP=O、Nd(NO)_2·2php=O·C_2HOH、La(NO_3)_3·3php=O·C_2H_5OH·CHCl_3和Nd(NCS)·4php=O。这些配合物晶体及分子结构各异,这表明了三苯基氧膦在形成配合物时的复杂性。本文报导的Nd(ClO_4)·4phP=O·C_2H_5OH实际上是由三部分组成;即[Nd(ClO_4)_2·4phP=O]~+外界的ClO_4和溶剂合分子。这在中性配体与高氯酸希土形成的配合物中时有发现。已知结构的 相似文献
1000.
Feng Zhao Yu-Kou Du Ping Yang Ji’an Tang Xing-Chang Li 《Colloid and polymer science》2005,283(12):1361-1365
In the present study, the structure and morphology of single sodium poly(styrenesulfonate) (PSS) molecules adsorbed to mica
surface from the natural aqueous solution is investigated using atomic force microscopy technique. Results show that single
PSS molecules are observed which show a morphology of wormlike coils. Meanwhile, single sodium poly(styrenesulfonate) (PSS)/Hexadecyltrimethylammonium
bromide (CTAB) complexes deposited on mica from the air–water interface are also observed. However, the PSS/CTA+ complexes show different conformations by appearing in the morphology of circular patches. Experimental data are in fair
agreement with the theoretical analysis. 相似文献