共查询到20条相似文献,搜索用时 15 毫秒
1.
ZnSe hollow spheres aggregated from nanoparticles with size of 60∼100 nm have been successfully synthesized via simple hydrothermal routes. NaOH and cetyltrimethyl ammonium bromide (CTAB) were used to control the shape and size, respectively. The as‐prepared microspheres were characterized with powder X‐ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV‐vis spectroscopy. The results indicate that the products are well dispersed and uniform. The effect of two additives was discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
P. Chithaiah S. Ashoka K. V. Thipperudraiah G. T. Chandrappa 《Crystal Research and Technology》2012,47(10):1075-1082
In this article, we report a novel but simple method for the phase transformation of ZnO2 to flower‐like ZnO microstructures hydrothermally at 90 °C with and without the assistance of hexadecylamine as surfactant. The generation of zincate ion ZnO$^{2-}_{2}$ as a growth unit from the reaction between ZnO2 and peroxide ion O$^{2-}_{2}$ in situ plays a key role in the phase transformation of ZnO2 to ZnO. The morphology, structure, and composition of the products have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Powder X‐ray diffraction (PXRD) and energy dispersive X‐ray analysis (EDX). It has been demonstrated that the as‐fabricated ZnO flowers are composed of self‐assembled brooms and rods in the presence and absence of hexadecylamine respectively. On the basis of experimental results, a possible reaction mechanism and the growth processes involved in the formation of flower‐like ZnO microstructures are discussed. 相似文献
3.
4.
水热法合成氧化锌晶体 总被引:15,自引:8,他引:7
本文采用水热法,通过改变矿化剂浓度,合成了具有不同晶体形态的氧化锌晶体.在430℃,填充度为35;,矿化剂浓度为1M KOH时,只合成了氧化锌微晶.氧化锌晶体的长度为几百纳米到几微米,晶体形状为六棱锥体.当矿化剂为3M KOH或2M KOH、1M KBr时,合成了高质量的氧化锌晶体.反应 24h后,合成的最大晶体长度(c轴方向)超过1mm,晶体呈单锥六棱柱体,显露柱面m{1010}、锥面p{1011}、负极面o面{0001}.另外还生成多种不同形态的微晶体,最小几微米,中等的几十微米,为六棱锥体,显露锥面p{1011}、负极面o面{0001},没有显露柱面. 相似文献
5.
Y. F. Zhu G. H. Zhou H. Y. Ding A. H. Liu Y. B. Lin N. L. Li 《Crystal Research and Technology》2010,45(10):1075-1078
In order to improve the performance of ZnO‐based solar cells, highly‐ordered hierarchical ZnO nanostructures were design and fabricated. The hierarchical nanostructures were grown on FTO (fluorine doped tin oxide, SnO2:F) glass substrates via a facile, low‐temperature, and low‐cost chemical route. The morphology and structure of the obtained products has been confirmed by field‐emission scanning electron microscopy and X‐ray diffraction measurements. The performance investigation of the prepared dye‐sensitized solar cells (DSSCs) demonstrates that the hierarchical ZnO nanostructure‐based solar cell shows a higher short‐circuit current density compared with the ZnO nanowire counterpart. The enhanced current density may be due to the fact that the surface area of the hierarchical nanostructures is increased. These results indicate that hierarchical ZnO nanostructures are more suitable for the application as photoelectrode of DSSCs. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
Shuling Xu Sixiu Sun Guozhu Chen Ting You Xinyu Song 《Crystal Research and Technology》2009,44(7):721-724
Hollow Cu2O nanocubes have been fabricated under solvothermal condition using N,N ‐dimethylformamide (DMF) as solvent at 120 °C for 12 h. The products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X‐ray powder diffraction (XRD) and high‐resolution transmission electron microscopy (HRTEM). Series of experiment confirmed that the amount of water, the reaction time and temperature played important roles in the morphology evolution of hollow Cu2O nanocubes. DMF is a relatively weak alkali solvent and could release a certain amount of OH– under the given conditions. As the release speed of OH– from DMF became substantially slow, the nucleation and growth of Cu2O nanocubes turned into kinetically controlled process. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
8.
Ning Wang Hongtao Pang Hongrui Peng Guicun Li Xiguang Chen 《Crystal Research and Technology》2009,44(11):1230-1234
Manganese oxide (MnO2) nanowires with diameters of 40–50 nm and lengths up to several micrometers have been successfully synthesized through a simply hydrothermal route. The influences of synthetic parameters, such as reaction time, and reaction temperature, on the growth and morphologies of MnO2 nanowires have been investigated. It is found that MnO2 nanowires can be evolved into MnO2 microrods with the reaction time/temperature increased. The electrochemical characterization of MnO2 nanostructures was carried out in 1 M Na2SO4 aqueous electrolyte at the scan rate of 10 mV s‐1. The results indicate that the MnO2 microrods obtained when the reaction performed at 200 °C for 24 h showed the best performance for supercapacitor. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
9.
Large‐scale high‐quality BaMoO4 nanocrystals have been synthesized in aqueous solutions under mild conditions with citrate as a simple additive. The crystals have bone‐like, spindle‐like and wheatear‐like morphologies assembled from nanoparticles, nanofibers and have been characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. The results showed that experimental parameters had great influences on the shape evolution of products. The adjustment of these parameters such as room temperature stirring time, reaction temperature and reaction time of hydrothermal reaction, can lead to obvious morphology changes of products, and the growth mechanism has been proposed. Room‐temperature photoluminescence indicated that the as‐prepared BaMoO4 nanocrystals had a strong blue emission peak at 481.5 nm. This facile route could be employed to synthesize more promising nanomaterials with interesting self‐assembly structures. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
10.
Different morphologies of single‐crystalline orthorhombic phase bismuth sulfide (Bi2S3) nanostructures, including sub‐microtubes, nanoflowers and nanorods were synthesized by a urea‐assisted hydrothermal method at a low temperature below 120 °C for 12 h. The as‐synthesized powders were characterized by X‐ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM) and UV‐vis spectrophotometry. The experimental results showed that the sulfur sources had a great effect on the morphology and size of the resulting powders. The formation mechanism of the Bi2S3 nanostructures with different morphologies was discussed. All Bi2S3 nanostructures showed an appearance of blue shift relative to the bulk orthorhombic Bi2S3, which might be ascribed to the quantum size effect of the final products. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
11.
12.
Gallium orthophosphate (GaPO4) single crystals have been grown from phosphoric acid solutions under hydrothermal conditions. The crystals have been studied in terms of twinning because of the strong effect of this structural defect on the piezoelectric properties. The growth rates of individual faces have been compared to each other by considering the dipyramidal habit of the grown crystals. 相似文献
13.
Yongbin Xu Zhongming Ren Guanghui Cao Weili Ren Kang Deng Yunbo Zhong 《Crystal Research and Technology》2009,44(8):851-856
Large amounts of dumbbell‐like Sb2S3 microcrystals were synthesized via a simple solvothermal treatment method. Various techniques such as x‐ray diffraction (XRD), field‐emission scanning electron microscope (FESEM), high‐resolution transmission electron microscope (HRTEM), selected area electron diffraction (SAED), and photoluminescence spectrometry (PL) have been used to characterize the obtained products. The results showed that the products belong to the orthorhombic Sb2S3 phase, and the dumbbell‐like Sb2S3 microcrystals were composed by uniform microrods. Besides, the morphologies of Sb2S3 microcrystals could be changed from microshperes to dumbbell‐like microcrystals by only adjusting the reaction solvent. The solvent effects are discussed in detail. Furthermore, the PL properties of the obtained Sb2S3 microcrystals clearly show shape effects. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
Hierarchical flower‐like Bi2Te3 was synthesized through a facile solvothermal method. The crystal structure and morphology of the as‐prepared samples were characterized by X‐ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and high resolution TEM. The reaction parameters such as reaction time, the amount of glucose, concentration of NaOH and the reaction temperature were systematically investigated. Based on the FESEM observations, a possible mechanism defined as a self‐assembly process accompanied by anisotropic growth mechanism was proposed. Moreover, the thermoelectric properties were measured at the temperature range of 300–600 K. The hierarchical flower‐like Bi2Te3 presented good thermoelectrical properties. The maximum ZT value reached up to 0.6 at 600 K, which was higher than that of Bi2Te3 nanoparticles. 相似文献
15.
稀土离子掺杂氟化物晶体具有宽透光波段高透过率、低声子能量、长荧光寿命、负热光系数等优良特性,可以产生从紫外到中红外波段激光,是一类重要的激光增益介质。本文综述了本团队在稀土离子掺杂LiLuF4、LiYF4、BaY2F8、LaF3、PbF2、CeF3等氟化物晶体生长、光学和激光性能等方面的研究进展,总结了稀土离子共掺敏化、退激活、能级耦合调控以及多离子发光等方面的研究工作,展望了稀土离子掺杂氟化物激光晶体的研究发展趋势。 相似文献
16.
17.
18.
K. N. Shreekanthan B. V. Rajendra V. B. Kasturi G. K. Shivakumar 《Crystal Research and Technology》2003,38(1):30-33
Semiconducting thin films of cadmium selenide have been grown by conventional thermal evaporation technique. The effect of various growth parameters like rate of deposition and deposition temperature has been studied in detail. Films deposited at room temperature are cadmium rich with segregated selenium globules. A deposition temperature of 453 K has been found to yield stoichiometric, homogeneous films. The films have been analysed for optical band gap and thermal activation energies. Films of low electrical resistivity have been obtained for possible applications. 相似文献
19.
通过顶部籽晶法生长出掺5;和8;Sr2+的La2CaB10O19(LCB)晶体,ICP测得LCB晶体中Sr2+掺入量分别为1.75;和2.02;.XRD证实Sr2+的掺入对LCB晶体晶胞参数的影响较小.摇摆曲线测得Sr2+∶LCB晶体半高宽为36",表明晶体具有较高质量.Sr2+∶LCB晶体在300~2000 nm波段具有较高的透过率,紫外截止边为172 nm.拟合的色散方程符合Sr2+∶LCB晶体折射率的实验值,理论计算表明Sr2+∶LCB晶体可实现相位匹配,其最短二倍频波长小于LCB晶体. 相似文献
20.
ZnO films consisted of hollow nanostructures were prepared by a CTAB‐assisted chemical bath deposition (CBD) method. ZnO rings, bowls and assemblies of hollow structures were successfully obtained on different substrates. Dense ZnO films consisted of sunken prisms can also be achieved by controlling the concentration of CTAB. The influences of reactant concentrations, types of the substrates and pre‐coated ZnO nanoparticles on the formation of ZnO films were examined. XRD patterns indicated the Wurtzite structure of ZnO and the preferred growth direction is [001]. The role of CTAB in CBD process was discussed and the evolution of different ZnO nanostructures was studied based on the observation of SEM. A plausible crystal growth mechanism was proposed for the formation of ZnO rings and bowls. The investigation of optical properties showed that high concentration of CTAB can improve the ultraviolet emission. 相似文献