Hydrothermal synthesis of CdSe hierarchical dendrites using ionic liquid as template

Well-defined CdSe hierarchical dendrites have been synthesized through a facile and effective hydrothermal method. The as-formed CdSe dendrites possess good dispersity and have an average length of about 1 μm along the trunk. Most importantly, it is found that long-chain ionic liquid [C₁₆mim]Cl (1-hexadecyl-3-methylimidazolium chloride), which can adsorb on the (002) plane of wurtize CdSe driven by the coulomb force, serves as an effective template and plays a critical role for the morphology of the product. Furthermore, the UV-vis spectrum of the CdSe dendrites displays absorption maxima at 296 nm; therefore, the obtained CdSe dendrites might have promising application in blue emitters, gas sensors, and light-emitting devices.     

Preparation and characterization of CdSe nanoparticles in the presence of Triocytlphosphine as solvent and capping agent

Triocytlphosphine (TOP)-capped CdSe nanoparticles (NPs) have been successfully prepared by the one-pot solution growth method at 240 °C under argon atmosphere. In particular, The TOP used in this process as the single coordinating solvent is favorable for probing capping mechanism of CdSe NPs surface. The growth process and characterization of CdSe NPs were determined by photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM), Ultraviolet-visible (UV-Vis) spectroscopy and Fourier transform infrared spectroscopy (FTIR). Results demonstrated the TOP-capped CdSe NPs to be well dispersed and uniform in shape and the diameter of the particle was confined within 8 nm. PL measurement showed the near band-edge luminescence of the final product.     

Preparation of amino-acid-regulated hydroxyapatite particles by hydrothermal method

The hydroxyapatite nanorods (about 80 nm in length and 15 nm in width) with uniform size were achieved by hydrothermal method at 100 °C and pH 10 in the presence of alanine and glutamic acid. A special instillment order was used and the prepared powders were characterized for phase composition by X-ray diffraction and Fourier Transform infrared spectroscopy. The size and morphology of HAP nanoparticles were studied by Transmission electron microscopy. The characterization showed that the amino acid could induce the synthesis of hydroxyapatite nanoparticle and control HAP crystal growth when HAP crystal was formed. An instable monetite phase (CaPO₃OH) was found in the progress of ACP transforming to HAP.     

CdSe纳米棒的制备及光电性能研究

采用水热法制备了CdSe纳米棒,并用TEM、SEM、XRD、TGA-DTA对其进行了表征.结果表明,纳米棒直径在100nm左右,长度约300nm;纳米棒具有闪锌矿的结构;将CdSe纳米棒均匀涂在导电玻璃的导电面上,在400℃下煅烧30min后制备成纳米棒膜电极,并进行了光电化学研究,纳米棒膜结构电极最高单色光的光电转换效率(IPCE)可达74%.     

A task specific basic ionic liquid for synthesis of flower-like ZnO by hydrothermal method

Flower-like ZnO morphology, with different shapes, have been successfully synthesized via a novel and environment-friendly hydrothermal method using zinc acetate and a task specific dicationic dibasic ionic liquid, [mmpim]₂[OH]₂, which plays an important role in fabrication of ZnO structure. The structure and morphology of the product were characterized by X-ray diffraction and scanning electron microscopy, which show different flower-like morphologies. Photoluminescence spectrum of the product exhibits a strong ultraviolet emission at 391 nm and two weak blue-green emissions at about 450 and 500 nm.     

Preparation of Bi2S3 nanorods via a hydrothermal approach

Large-scale bismuth sulfide (Bi₂S₃) nanorods with uniform size have been prepared by hydrothermal method using bismuth chloride (BiCl₃) and sodium sulfide (Na₂S·9H₂O) as raw materials at 180 °C and pH = 1-2 for 12 h. The powder X-ray diffraction (XRD) pattern shows the Bi₂S₃ crystal belongs to the orthorhombic phase with calculated lattice constants a = 1.1187 nm, b = 1.1075 nm and c = 0.3976 nm. Furthermore, the quantification of X-ray photoelectron spectra (XPS) analysis peaks gives an atomic ratio of 1.9:3.0 for Bi:S. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopic (TEM) studies reveal that the appearance of the as-prepared Bi₂S₃ is rod-like with typical lengths in the range of 2-5 μm and diameters in the range of 10-30 nm. Finally the influences of the reaction conditions are discussed and a possible mechanism for the formation of Bi₂S₃ nanorods is proposed.     

Synthesis of indium oxide cubic crystals by modified hydrothermal route for application in room temperature flexible ethanol sensors

Indium oxide cubic crystals were prepared by using hexamethylenetetramine and indium chloride without the addition of any structure directing agents. The chemical route followed in the present work was a modified hydrothermal synthesis. The average crystallite size of the prepared cubes was found to be 40 nm. A blue emission at 418 nm was observed at room temperature when the sample was excited with a 380 nm Xenon lamp. This emission due to oxygen vacancies made the material suitable for gas sensing applications. The synthesized material was made as a composite film with polyvinyl alcohol which was more flexible than the films prepared on glass substrates. This flexible film was used as a sensing element and tested with ethanol vapours at room temperature. The film showed fast response as well as recovery to ethanol vapours with a sensor response of about 1.4 for 100 ppm of the gas.     

CdSe纳晶薄膜电极的制备及其光电性能研究

利用化学溶液沉积法制备了CdSe纳晶薄膜,并用透射电子显微镜和扫描电子显微镜的EDS对其形貌和化学组成进行了表征.对CdSe纳晶薄膜电极的吸收光谱和光电性能进行了测试,结果表明,CdSe纳晶薄膜可以获得较好的光电流,这种薄膜电极改进后,可用于制作敏化太阳能电池的光阳极.     

Growth of novel multi-trunk CdS dendrites by hydrothermal method without surfactant

In the current paper, novel multi-trunk CdS dendrites were synthesized via a simple hydrothermal system, employing CdCl₂·2H₂O and KSCN as the starting materials. No extra surfactants were used. The observations from TEM and SEM showed that the product composed of a few long central trunks with secondary branches, which preferentially grew in a parallel direction with a definite angle to the trunks. Selected area electron diffraction (SAED) patterns confirmed that the dendrite was single crystalline in nature. X-ray diffraction analyses proved that the CdS dendrites were pure hexagonal structure. On the basis of the experimental results, a possible growth process has been discussed.     

Fabrication of mesoporous carbonated hydroxyapatite microspheres by hydrothermal method

Mesoporous carbonated hydroxyapatite microspheres (MCHMs) have been converted from calcium carbonate microspheres (CCMs) by hydrothermal method. After soaking the CCMs in disodium hydrogen phosphate solutions, carbonated hydroxyapatite nanoparticles are formed via a dissolution-precipitation reaction. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) reveal that the as-obtained samples are calcium deficient hydroxyapatite with B-type CO₃²⁻ substitution. The transmission electron microscopy (TEM) indicates that the MCHMs are composed of many nanoparticles within the whole microspheres. These nanoparticles aggregate to form mesopores with a pore size of 4.5-14.0 nm among them. The formation mechanism of MHAMs has been discussed.     

Surfactant Assisted Hydrothermal Synthesis of CdSe Nanostructural Materials

CdSe/CTAB composite nanostructural materials were successfully synthesized at 160-200 ℃ for 2 days through a facile surfactant(cetyl trimethyl ammonium bromide-CTAB) assisted hydrothermal method using cadmium acetate and sodium selenate as precursor.The obtained products were characterized by X-ray diffraction,energy dispersive X-ray analysis,Fourier transform infrared spectroscopy and thermo gravimetric analysis.Optical properties were studied by photoluminescence and UV-visible spectroscopy and morphology was investigated by scanning electron microscopy.     

CdSe新型纳米结构的合成及光学性能研究

采用水-离子液体(溴代1-丁基-3-甲基咪唑盐,[Bmim]Br)为溶剂,以CdCl2和Na2SeSO3为反应物,在水热条件下于120℃制备出具有新型纳米结构的CdSe。利用XRD、SEM和EDS对产物的物相结构和形貌等进行分析,结果表明产物为分散性良好、平均粒径约为3μm的纤锌矿CdSe微米球,并且制备的CdSe微米球由平均直径约为100nm的纳米棒组装而成。CdSe新型纳米结构的紫外-可见光谱在282nm处出现最大吸收峰,发生了显著的蓝移,表现出显著的量子尺寸效应。     

A novel method for the preparation of water-soluble and small-size CdSe quantum dots

A novel method for the preparation of water-soluble and small-size CdSe quantum dots has been reported under high-intensity ultrasonic irradiation. The as-prepared products have been characterized by absorption spectra, X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM).     

A facile method to synthesize hierarchical SiO2@CdSe and CdSe hollow spheres

In this paper, a facile method was developed to synthesize SiO₂@CdSe particles by using silica colloidal spheres which efficiently avoided complex prior surface modification. In the experiment, ammonia was introduced to activate silica colloidal spheres with negative charge, which acted as active sites for the nucleation of CdSe nanocrystals around silica colloidal spheres. Then the corresponding CdSe hollow spheres were obtained by dissolving the silica cores. The TEM results exhibited CdSe hollow spheres were consisted of nanorods. On the basis of experimental results, the formation process of the hollow spheres was studied and possible growth mechanism for one-step coating process was proposed.     

Aqueous synthesis of luminescent magic sized CdSe nanoclusters

Highly stable water-soluble CdSe nanoclusters (NCs) with magic size were successfully synthesized using homocysteine (HCY) as capping ligands. Their sizes were tunable between 1.2 and 2.0 nm depending on reflux time. The final products were characterized by UV-vis absorption, steady and time-resolved photoluminescence (PL) spectra, X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). XRD analysis showed that the HCY-capped CdSe NCs were of the cubic structure, UV-vis absorption spectra and HRTEM micrograph exhibited that the NCs were nearly monodisperse and relatively uniform. The as-prepared CdSe NCs had a PL quantum yield of up to 1.4%, almost comparable to the CdSe magic sized clusters prepared by an organometallic route.     

Facile synthesis and characterization of urchin-like CdSe nanostructures

CdSe nanostructures with urchin-like shape were successfully synthesized in water-in-oil (W/O) microemulsion. The phase structure, morphology, optical property, and specific surface area of the CdSe products were characterized. The X-ray powder diffraction pattern of the product showed that it is pure CdSe in zinc blende structure rather than thermodynamically favored wurtzite structure. It is found that numerous one-dimensional CdSe nanorods radiate from the center of the agglomerate to form urchin-like nanostructures and grow along the (111) crystal planes. The photoluminescence spectrum of the urchin-like nanostructures indicated that there is a blue-shift as compared with that of the bulk CdSe. Additionally, these interesting urchin-like nanostructures showed an increased specific surface area.     

水热法制备CdS纳米结构

利用氯化镉(CdC12)、硫脲(CO(NH2)2)和聚乙烯吡咯烷酮(PVP),在水热条件下获得了玉米棒状和花状等不同形貌的CdS纳米结构.采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、荧光发光光谱(PL)、紫外可见光分光光度计(UV-vis)对产物进行表征.结果表明:PVP对不同形貌CdS纳米结构的形成起关键作用,随着PVP量的增加,PVP选择性地吸附(102)晶面,抑制了该(102)晶面方向的生长,使产物的形貌由玉米棒状转变为花状;而花状纳米结构的紫外的吸收产生了红移现象,荧光性能无明显变化.     

Template-free hydrothermal synthesis of PbS nanorod by the oriented attachment mechanism

In this work, PbS nanocubes and nanorods were fabricated via a facile hydrothermal method without using any template and surfactant. The structure and morphology of as-prepared PbS nanocrystals were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). It was found that the anisotropic structure of PbS nanorods were composed of numerous assembled nanocubes, which had an uniform morphology with the mean diameters of about 100-200 nm and lengths of 0.5-7 μm. Furthermore, a possible growth mechanism was proposed to explain the formation of the nanorods on the basis of the time-dependent experimental results.     

不同晶型 CdSe纳米棒的制备及光电性能研究

采用水热法制备了不同晶型CdSe纳米棒,并用TEM、SEM、XRD、TGA-DTA对其进行了表征.结果显示反应温度为240℃生成纤锌矿型CdSe纳米棒,反应温度为200℃生成闪锌矿型CdSe纳米棒.并对纳米棒进行了光电性能测定,纤锌矿型CdSe纳米棒膜电极的光电转换效率（IP.CE）优于闪锌矿型CdSe纳米棒膜电极的IPCE.CdSe/PMeT复合膜电极在具有最大光电转换效率时的波长发生了红移.