Synthesis of uniform CdS nanowires in high yield and its single nanowire electrical property

Large-scale high quality CdS nanowires with uniform diameter were synthesized by using a rapid and simple solvothermal route. Field emission scan electron microscopy (FESEM) and transmission electron microscopy (TEM) images show that the CdS nanowires have diameter of about 26 nm and length up to several micrometres. High resolution TEM (HRTEM) study indicates the single-crystalline nature of CdS nanowires with an oriented growth along the c-axis direction. The optical properties of the products were characterized by UV-vis absorption spectra, photoluminescence spectra and Raman spectra. The resistivity, electron concentration and electron mobility of single NW are calculated by fitting the symmetric I-V curves measured on single NW by the metal-semiconductor-metal model based on thermionic field emission theory.     

溶剂热法制备MWNTs/CdS复合材料

分别以醋酸镉和硫脲为原料,二乙三胺和去离子水为混合溶剂,采用溶剂热技术制备了MwNTs/CdS复合材料,并用TEM、XRD、FT-IR及UV-vis等技术对材料的结构、形貌和性质进行表征.研究结果表明:硫化镉纳米粒子附着在多壁碳纳米管表面,且无团聚现象.     

Facile synthesis and characterization of uniform CdS colloidal spheres

Uniform CdS colloidal spheres have been successfully synthesized via a simple hydrothermal method.X-ray diffraction(XRD) analyses indicate that the products exhibit a hexagonal structure.Scanning electron(SEM) and transmission electron microscopy (TEM) are used to characterize CdS colloidal spheres.The final size of the spheres may be selected from a range of 71±2 nm to approximately 181±5 nm by changing the amount of polyvinylpyrrolidone(PVP) and hexamethylenetetramine(HMT).The CdS colloidal spheres are not obtained in the absence of either of the capping agents.A synergistic effect between HMT and PVP is proposed to be crucial for the formation of colloidal spheres.     

Solvothermal synthesis of uniform and high aspect ratio of CdS nanowires and their optical properties

Uniform and high aspect ratio CdS nanowires (NWs) were successfully synthesized by the solvothermal reaction of the solution containing Cd(NO₃)₂, (NH₄)₂S and ethylenediamine (NH₂(CH₂)₂NH₂). In this research, the effects of molar contents of the stating materials, reaction temperatures and lengths of time on phase, vibration modes, morphologies, and optical properties of the as-synthesized products were studied using XRD, Raman spectroscopy, SEM, TEM, SAED, HRTEM, UV–vis spectroscopy and PL spectroscopy. They were found to be controlled by the contents of the stating materials, reaction temperatures and lengths of time. Mixed nanoparticles and short nanorods of CdS were synthesized by the 200 °C and 24 h solvothermal reaction of the solutions containing 0.0001–0.0050 mol of the starting materials. Upon increasing the content of the starting materials to 0.0100 mol, the completely uniform CdS NWs with aspect ratio of >250 were synthesized.     

有机硫源溶剂热法合成CdS纳米晶体

以二硫化四甲基秋兰姆((TMTD)作为有机硫源,分别在苯、水-苯溶剂中于不同温度、不同时间溶剂热法合成了CdS纳米晶体。采用FE-SEM、XRD和FTIR对晶体的结构和成形机理进行了研究。结果表明,溶剂热温度比反应时间对晶体形貌的形成影响更大。CdS纳米晶体是立方与六角的混合晶型。此外,溶剂的种类也是影响CdS纳米晶体结构和成形的重要因素,并且对花形CdS纳米晶体进行了阴极发光(CL)光谱的研究。     

纳米钒铬复合氧化物的溶剂热合成、表征及催化2,6-二氯甲苯氨氧化反应（英文）

甲基芳烃气相氨氧化反应制备对应的芳香腈被认为是丙烯氨氧化制备丙烯腈之后化工领域又一重大进展,芳香腈是重要的精细化学品,广泛应用于医药、农药、颜料、染料、橡胶、光电材料等领域.其中2,6-二氯甲苯氨氧化反应制备2,6-二氯苯腈是特别重要的反应,2,6-二氯苯腈工业上可用于制备高效除草剂、杀菌剂及各种特种工程塑料;然而相较于其它的甲基芳烃,2,6-二氯甲苯由于甲基邻位有两个较大位阻且较强吸电子的氯原子影响,甲基活性较低,较难发生氨氧化反应,原料转化率和产品收率均较低.本课题组一直致力于发展高活性和选择性的氨氧化催化剂以及有效的策略实现甲基芳烃高效转化为芳香腈,我们曾以硅胶负载的钒磷氧化物(VPO/SiO_2)和钒铬氧化物(VCrO/SiO_2)为催化剂,成功实现了2,6-二氯甲苯氨氧化反应制备2,6-二氯苯腈.钒铬复合氧化物(VCrO)具有广泛的应用,可用于多相催化、气体传感、能量储存等领域.VCrO通常通过高温固相反应制备,然而一般得到的是混合相,产品形态和颗粒大小也不能很好控制;当用于氧化或氨氧化反应时,需要较高的反应温度,原料也容易发生过度氧化,导致积碳及活性降低.我们以V_2O_5和CrO_3为原料,在醇或者醇水溶液中于180℃进行溶剂热反应制备了无定形的VCrO前驱体,然后将前驱体在不同温度下氮气气氛中煅烧,产品通过粉末X射线衍射、透射电镜和X射线光电子能谱等进行表征.当以甲醇或甲醇水溶液为溶剂热反应介质,并且前驱体700℃进行煅烧后,产品为纯的正交晶系CrVO4纳米晶相;当以甲醇为溶剂时,CrVO_4晶相的尺寸大约为500 nm;而改为甲醇水溶液为溶剂时,产品尺寸急剧减小到50 nm以下,而且通过改变甲醇和水的体积比分别为10:1,5:1,1:1和1:5时,CrVO_4纳米晶相的尺寸从50 nm逐渐减小到30,20和10 nm,能够进行有效调控.据我们所知,这是首次合成纯的CrVO_4纳米晶相.我们以该纳米CrVO4为催化剂催化2,6-二氯甲苯氨氧化反应制备2,6-二氯苯腈,在335℃的相对较低温度下反应,原料转化率为84%,产品收率为75%;进一步升高温度到390℃,原料转化率为99%,产品收率可达81%.在所有已报道的二元复合氧化物催化剂中,纳米CrVO_4显示了最高的催化活性,主要归功于它较小的粒子尺寸、较大的表面积和更多暴露的活性中心     

溶剂热合成单分散硫化镉纳米晶

在双表面活性剂十八胺和油酸存在条件下, 以氯化镉和硫粉作为反应前驱物, 通过简单的溶剂热方法合成单分散性闪锌矿硫化镉纳米晶, 粒径大小在13 nm. 用X射线衍射(XRD)、透射电子显微镜(TEM)对产物的结构和形貌进行了表征, 同时对硫化镉纳米晶的紫外吸收谱和光致发光谱(PL)性能进行了表征. 实验结果表明合成的样品具有很好的发光性能, 此外溶剂热反应的温度对纳米晶的单分散性有重要影响. 并对硫化镉纳米晶的形成机理做了初步的研究.     

CdS纳米球的水热制备及性质表征

采用水热方法制备了CdS纳米球.通过扫描电镜和透射电镜可以看出:该方法可直接获得具有较好结构的纳米球,比较不同溶剂中得到产品的SEM,发现甘油对CdS纳米球的形成起到了重要的作用.X射线粉末衍射图谱中无杂质衍射峰出现,表明样品为纯的六方相CdS.CdS纳米球的室温光致发光光谱中有2个不同的峰.     

Solvothermal synthesis and structural characterization of a novel erbium(III)-carboxylate polymeric complex

A novel erbium(III)-carboxylate polymeric complex [{Er(H₂btec)_2/4(btec)_3/6(H₂O)}·2H₂O] _n , simplified as ECPC, (H₄btec=1,2,4,5-benzenetetracarboxylic acid) was synthesized under solvothermal conditions (H₂O/acetic acid). ECPC obtained was characterized by differential thermal analysis/thermogravimetry (DTA/TG), single-crystal X-ray diffraction, elemental analysis and FT-IR analysis techniques. The result of single-crystal X-ray diffraction analysis shows that the ECPC crystallizes in monoclinic symmetry, and the space group P2(1)/n, a=10.6933(15) Å, b=7.1243(10) Å, c=17.092(2) Å, α=γ=90°, β=97.109(2)°, V=1292.1(3) Å³, Z=4, R ₁=0.0286, wR ₂=0.0686. ECPC demonstrates a 3-D supramolecular framework containing nine-coordinate erbium centers and channels. The uncoordinated water molecules occupy the channels in ECPC. The results of TG/DTA, IR and elemental analysis performed also give positive information of the proposed crystal structure.     

Solvothermal synthesis and characterizations of monophenyltin complexes in drum conformations

A series of drum structures of organotin complexes with various carboxylic acids have been solvothermally synthesized and characterized by elemental analysis, FT-IR, NMR (¹H, ¹³C and ¹¹⁹Sn) spectra and X-ray crystallography. The molecular structure analyses reveal that all of the complexes have endo drum structures. Furthermore, each of the drum structures has a hole, in which atoms of a given radius could be held.     

Simple synthesis of ultra-long Ag2Te nanowires through solvothermal co-reduction method

Ultra-long single crystal β-Ag₂Te nanowires with the diameter of about 300 nm were fabricated through a solvothermal route in ethylene glycol (EG) system without any template. The long single crystal wires were curves, with high purity, well-crystallized, and dislocation-free and characterized by using X-ray powder diffraction (XRD), Differential scanning calorimetry (DSC) analysis, X-ray photoelectron spectroscope (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high-resolution transmission microscopy (HRTEM). The detailed topotactic transformation process from particles into single crystal wires was studied. Furthermore, the electrical conductivity and Seebeck coefficient have been systematically studied between 300 and 600 K.     

聚乙烯醇辅助合成CdS纳米线及其表征

以聚乙烯醇为辅助剂, 使用溶剂热法成功制备CdS纳米线, 并用XRD、TEM、HRTEM、UV-Vis和PL(荧光)发射谱等方法对样品进行表征. 结果表明, 该法制备的CdS纳米线为六方纤锌矿结构, 直径为70 nm, 长约10 μm, 沿[001]晶向择优生长, 具有量子禁域效应. 同时, 根据对比实验结果提出了CdS纳米线的聚合物辅助生长机理.     

Solvothermal synthesis and crystal structure of a 3-D hexagonal metal-porphyrin coordination network

A hexagonal-shaped hybrid metal-porphyrin framework containing 5,15-di(4-pyridyl)-10,20-diphenylporphyrin (trans-H₂DPyP) and Zn(NO₃)₂6H₂O in DMF has been self-assembled solvothermally. The solvothermal reaction of Zn(II) with conformationally versatile 5,15-di(4-pyridyl)-10,20-diphenylporphyrin, which can coordinate axially to two ligands, resulted in metalation of the porphyrin core and then self-coordination of the metalated porphyrin-produced single crystals of 3-D polymeric arrays. The trans-ZnDPyP framework is thermally stable at 450?°C and allows solvent exchange without losing the crystal structure.     

Solvothermal synthesis of CdS nanowires in a mixed solvent of ethylenediamine and dodecanethiol

CdS nanowires with an average diameter of 25 nm and lengths of 20-40 mum have been solvothermally synthesized in a mixed solvent of ethylenediamine and dodecanethiol at 180 degrees C. The time-dependent examinations reveal that the formation process of CdS nanowires involves two sequential processes: a short-period solid-solid transformation process in the initial stage and a long-period Ostwald ripening process. The effect of both the volume ratios between the two components of the solvent and the reaction temperatures on the nanowire growth has also been investigated in detail. The results of the photoluminescence and UV-vis spectroscopy measurements reveal that the as-prepared CdS nanowires show a quantum confinement effect.     

Solvothermal synthesis of PbTe/SnTe hybrid nanocrystals

PbTe/SnTe hybrid nanocrystals with designed shape, chemical composition and narrow size distribution were synthesized by an efficient solvothermal approach. This approach enables mass and economical synthesis of PbTe-based nanocrystals. The organic ligands were completely removed by pretreatment with a super-hydride solution, making it possible to fabricate fully dense and robust thermoelectric devices with increased electrical conductivity.     

无机-有机杂化层状锑硫化合物的溶剂热合成与结构

用溶剂热法合成了有机杂化层状锑硫化合物[C3H7NH3]2Sb4S7,并利用单晶X-射线衍射测定了其晶体结构。该化合物为三斜晶系,Pī空间群。晶胞参数:a=7.0098(10),b=11.9710(14),c=13.6685(17),α=115.244(6)°,β=98.671(9)°,γ=92.413(13),°V=1018.3(2)3,Z=2,Mr=831.71 g.mol-1,(=5.984 mm-1,F(000)=772,偏差因子R1=0.0334,wR2=0.0766。该化合物由质子化正丙胺离子[C3H7NH3] 和二维阴离子[Sb4S7]n2n-组成,[Sb4S7]n2n-二维离子由3个SbS3三角锥和1个SbS4变形四面体单元连接而成,[C3H7NH3] 离子位于无机阴离子层之间,形成三明治夹心式结构,[C3H7NH3] 的-NH3 基团与无机阴离子层的S原子形成N-H…S氢键作用。     

[VO(dien)]2GeS4: Solvothermal Synthesis and Crystal Structure with an Ortho‐Thiogermanate as Tetradentate Ligand

The compound [VO(dien)]₂GeS₄ ( 1 , dien = diethylenetriamine) features an ortho‐thiogermanate anion [GeS₄]^4–, which acts as tetradentate ligand joining [VO(dien)]^2– complexes. The compound was obtained under solvothermal conditions crystallizing in thenon‐centrosymmetric orthorhombic space group Pna2₁ with a =19.8310(11), b = 8.0814(5), c = 12.0889(9) Å, V = 1937.4(2) ų and Z = 4. The V⁴⁺ cations are in a distorted octahedral environment of a tridentate dien molecule, one oxygen atom and two sulfur atoms from the [GeS₄]^4– anion. A three‐dimensional network is generated by hydrogen bonding interactions.     

Construction of strong alkaline hydrothermal environment for synthesis of copper telluride nanowires

Strong alkaline hydrothermal environment was constructed through adjusting the KOH concentration in solution for the synthesis of Cu_2−xTe nanocrystals. The Cu_2−xTe nanowires were successfully obtained by hydrothermal method without using any template or capping agent. The as-synthesized nanowires were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). The Cu_2−xTe nanowires with lengths up to hundreds of micrometers have a single crystal hexagonal structure and grow along the [11], [12], [13], [14], [15], [16], [17], [18] , [19] and [20] direction. A growth mechanism was proposed based on the characterization results. The energy gap of as-synthesized Cu_2−xTe nanowires is ca.1.1 eV for direct band transition or 0.7 eV for indirect band transition. The structural phase transformations occur at 322, 353 and 477 °C. And the Cu_2−xTe nanowires exhibit the metal electrical conductivity.     

溶剂热法合成CdS纳米晶及其光学性质研究

以硫脲和醋酸镉为原料,采用溶剂热法在不同的反应介质和温度下合成了CdS纳米晶,比较了单胺与双胺对合成CdS纳米晶形貌的影响。采用透射电镜(TEM)、X射线粉末衍射仪(XRD)和荧光分光光度计(PL)对合成的CdS纳米晶结构和光学性能进行表征。结果表明:反应温度和反应介质对其形貌有影响,在双胺的条件下,60℃时合成了纯相的六方相CdS纳米棒;双胺条件下更易生成纳米棒,且高温下晶体的结晶性更好。PL分析表明,水(溶剂)热法制备的CdS的荧光光谱图与大多数CdS类似,均在440~480 nm和550 nm处存在发射峰,但较宽的发射峰蓝移说明材料的光学性质受到材料形貌和制备方法的影响。