SnS片状纳米晶的制备及其表征

用水热法制备了SnS片状纳米晶.通过X射线衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM),X射线能谱(EDS)等方法对所制备的样品SnS粉晶的结构形貌及组分进行了表征.研究了影响合成SnS片状纳米晶的几个因素,讨论了片状纳米晶生长过程与(040)晶面择优取向的关系,并分析了SnS片状纳米晶的合成机理.     

空气中旋涂热解快速制备高化学计量比SnS2薄膜

为快速制备高化学计量比的SnS2薄膜,介绍了一种简单的旋涂热解法,以SnCl4·5H2O和硫脲分别为Sn源和S源,在空气中及热解温度分别为200℃、260℃和320℃时制备了系列SnS2薄膜,这是首次使用旋涂热解法制备SnS2薄膜的尝试.采用EDS、XRD、Raman、SEM、UV-Vis等手段研究了热解温度对SnS2薄膜元素组成、晶相、形貌、光学吸收等的影响,在热解温度为260℃且仅需热解2min条件下,获得了Sn/S原子比为1/1.98的高化学计量比SnS2薄膜,该薄膜直接禁带宽度为2.50eV,非常适合作为太阳能电池窗口层.     

不同缓冲层对ZnO薄膜的性能影响

用射频反应磁控溅射法在玻璃基底上分别以SnO2、SiO2和Al2O3为缓冲层制备ZnO薄膜.利用X射线衍射仪(XRD)、扫描电镜(SEM)、紫外-可见分光光度计和荧光分光光度计对薄膜的结构和光学性能进行了表征.XRD和SEM的分析结果表明,在SiO2和Al2O3缓冲层上生长的ZnO薄膜具有较好的c轴择优取向,薄膜表面光滑平整,薄膜的结晶质量得到改善;透射光谱表明所有样品在可见光范围内的平均透过率超过70;;通过对薄膜光致发光谱的分析,认为422 nm左右的紫峰来自于电子从晶粒边界的界面缺陷能级到价带的辐射跃迁;PL谱中蓝光和绿光的发光机制与薄膜中的本征缺陷有关.     

LiAlO2衬底上ZnO薄膜的溶胶-凝胶法制备和表征

采用溶胶凝胶法在LiAlO2(302)衬底上制备了ZnO薄膜.用X射线衍射(XRD)和扫描电镜(SEM)对样品的结构和形貌进行了表征.XRD结果表明,随着热处理温度的升高(350℃、450℃、550℃、600℃、800℃),所得到的薄膜分别为单相ZnAl2O4(350℃),ZnAl2O4和ZnO的混合相(450℃)以及单相的ZnO(550℃、600℃、800℃),并且ZnO薄膜c轴择优取向的生长趋势随温度升高相应明显.SEM图像显示,随着热处理温度的升高,ZnO薄膜的粒径相应变大.     

超声辅助液相合成多晶SnS纳米粉

本文以Na2S·9H2O和SnCl2·2H2O为反应源物,采用超声辅助液相合成法制备SnS纳米粉.用XRD、TEM和TED等方法对粉体样品进行了表征,检测结果表明粉体样品为具有斜方晶体结构的SnS纳米微粒,其平均晶粒尺寸约为15～25nm.论文还简要讨论了超声波对SnS纳米粉形成的影响,分析认为超声辅助手段的加入有利于多晶SnS纳米粉的形成.     

常规退火与光退火固相晶化的对比

为研究传统炉子退火与光退火固相晶化的不同特点,用石英玻璃作衬底,在室温、350℃和450℃下用PECVD法直接沉积非晶硅(a-Si:H)薄膜,把沉积的样品分别在850℃下用传统炉子退火3h、用光快速热处理(RTP)5min,然后用Raman、XRD和SEM分析对比,发现传统炉子退火后的晶粒分布不均匀,光退火后的晶粒分布均匀.XRD分析发现两种方法晶粒尺寸均为30nm左右.     

不同硫源对微波水热法制备SnS粉体结构和光学性能的影响

采用微波水热法,以氯化亚锡为锡源,硫化铵、硫脲、硫代乙酰胺、硫代硫酸钠等为硫源,在相同的条件下制备SnS粉体,研究了不同硫源对产物物相、形貌和光学性能的影响.采用XRD、SEM、TEM对样品的物相和形貌进行了分析.结果表明:除硫代硫酸钠外,由其他硫源制备的产物均为正交晶系的SnS粉体;通过不同的硫源可制备类球形、不规则长方体和花簇状SnS微晶.利用紫外-可见吸收光谱分析,产物的光学带隙约为1.48～1.61eV;室温光致发光光谱表明,产物在830 nm处具有近红外发光特性.     

N掺杂MgxZn1-xO薄膜结构和光学性质研究

采用溶胶-凝胶法在玻璃衬底上制备了N掺杂MgxZn1-xO薄膜.通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射光谱、光致发光(PL)谱对N掺杂MgxZn1-xO薄膜样品的晶体结构、表面形貌和光学性能进行了研究.XRD结果表明所有样品均形成了MgZnO合金薄膜,没有观察到其它氧化物的衍射峰.样品的结晶质量越差,样品的表面形貌越不规则,但样品在可见光的透射率越强,甚至达到了95;.样品的禁带宽度随Mg含量的增加而增加,随N含量的增加而减小.所有样品的光致发光谱均观察到强的400 nm发光和弱的可见发光.400 nm的发光强度随Mg含量的增加而减弱,随N含量的增加而增强,认为薄膜在400 nm的发光来源ZnO的激子复合.     

花状SnS2微球锂离子电池负极材料制备及性能

以SnCl4·5H2O和L-半胱氨酸为原料,通过水热法制备了直径约为1μm的均匀花状SnS2微球.利用X-射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)和氮气吸附-脱附测试(BET)对产物进行表征.电化学性能测试表明,花状SnS2微球作为锂离子电池负极材料,在1C电流密度下首次放电容量达到1379.5 mAh·g-1,30周后放电容量保持在400 mAh·g-1.     

Sn掺杂对ZnO薄膜结构和光电性能的影响

采用溶胶-凝胶浸渍提拉法在玻璃衬底上制备了Sn掺杂ZnO(SZO)薄膜。通过X射线衍射(XRD)和扫描电镜(SEM)研究了Sn掺杂对薄膜表面形貌和微结构的影响。XRD结果表明,所有ZnO薄膜样品都存在(002)择优取向。SEM结果表明随着掺杂浓度的增加,薄膜表面由颗粒向纳米棒转变。电学结果显示掺杂浓度为3at%时,电学性能最好,最低电阻率为6.9×10-2Ω.cm。室温光致发光谱(PL)显示所有的SZO薄膜样品在(325 nm光激发下)380 nm和398 nm两处都有发光峰,随着掺杂浓度的增大,398 nm处的发光强度先增大后减小,然后再增大;380nm处的发光强度始终增大,这些现象与薄膜的表面结构的变化有关。     

Triethyl ammonium salt of O,O′-bis(p-tolyl)dithiophosphate, [Et3NH]+[(4-MeC6H4O)2PS2]−

Triethyl ammonium Salt of O,O′-bis(p-tolyl)dithiophosphate and O,O′-bis(m-tolyl)dithiophosphate have been obtained by reaction of p- and m-cresol, respectively with P₂S₅ in toluene and have been characterized by elemental analysis, IR, ¹H and ³¹P NMR spectroscopy. The molecular structure of O,O′-bis(p-tolyl)dithiophosphate has been determined. Crystal data: [Et₃NH]⁺[(4-MeC₆H₄O)₂PS₂]⁻: Monoclinic, P2₁/c, a=15.2441(9) ?, b=10.415(2) ?, c=3.9726(9) ?, β=91.709(7)°, V=2217.5(1) ?⁻³, Z=4.Supplementary materials Additional material available from the Cambridge Crystallographic Data Centre (CCDC no. 600927 for [Et₃NH]⁺[(4-MeC₆H₄O)₂PS₂]⁻ comprises the final atomic coordinates for all atoms, thermal parameters, and a complete listing of bond distances and angles. Copies of this information may be obtained free of charge on application to The Director, 12 Union Road, Cambridge CB2 2EZ, UK (fax: +44-1223-336033; email: deposit@ccdc.cam.ac.uk or www:http://www.ccdc.cam.ac.uk).     

First-principles coexistence simulations of supercooled liquid silicon

We perform first-principles coexistence simulations of the low-density and the high-density phases of supercooled liquid silicon and find a negative slope for the coexisting line in the temperature-pressure plane. Electron density maps and electron-localization function plots of the two phases of silicon show marked differences. The calculated differences suggest more localized electrons in the low-density liquid compared to the high-density liquid, coming from an increased population of covalent bonds, which further explain the calculated negative slope in the two phase coexistence regime. This is consistent with the presence of a pseudo-gap in low-density liquid silicon, absent in the high-density liquid which shows a metallic behavior.     

Crystal structures of thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane

Structures of both thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane, ?C₆H₄?CH₂SCH₂?C₆H₁₀?CH₂SCH₂?, have been determined, wherecis andtrans refer to the attachments to the cyclohexane ring. Thecis form crystallizes in the monoclinic space groupP2₁/c witha=8.4299(11)Å,b=21.772(2)Å,c=8.9724(13)Å, β=116.574(11)^o, andZ=4. Thetrans isomer packs into the monoclinic space groupP2₁ witha=8.159(16)Å,b=10.185(5)Å,c=9.558(2)Å, β=112.435(18)^o, andZ=2. The cyclohexane ring of thecis isomer is in the chair conformation, while the cyclohexane of thetrans isomer is found in a twisted boat conformation.     

CTAB与SDBS对碳酸锶粒子生长形态调控及机理研究

以表面活性剂CTAB和SDBS为化学添加剂,采用化学共沉淀法对碳酸锶晶体的生长形态进行调控,成功地制备出了实心的树枝状和花瓣为空心的花状碳酸锶粉体,并用X射线衍射(XRD)、扫描电子显微镜(SEM)和傅里叶变换红外光谱(FT-IR)等分析手段对样品进行了表征;最后重点对化学添加剂可能产生的影响机理进行了初步的探讨.结果表明,CTAB和SDBS在晶体生长的过程中能起到显著的影响作用,两者对粒子分散性能的作用效果相反,而且后者对晶体(013)和(213)晶面表面能降低的贡献明显大于前者.     

Crystal structures of the cis and trans isomers of a tetrathia[3.3.3.3]cyclophane

Both the cis and trans isomers of 3,11,18,26-tetrathiatricyclo[26.2.2.1^5,9.2^13,16.1^20,24] hexatriaconta-5,7,9,20,22,24-hexene have been prepared and structurally characterized. Each of these centrosymmetric tetrathia dimers includes two cyclohexane rings in chair conformations with either 1,4-cis or 1,4-trans bonding and two meta-substituted benzene rings. The cis isomer packs into the monoclinic space group P2₁/a with a = 10.485(3)Å, b = 10.3956(18)Å, c = 14.1343(10)Å, = 105.200(13)°, Z = 2 and refined to an R factor of 0.046. The trans isomer crystallizes in the monoclinic space group P2₁/c with a = 10.7217(12)Å, b = 5.6797(7)Å, c = 25.415(5)Å, = 96.001(12)°, Z = 2 and refined to an R factor of 0.043. In the cis structure each benzene ring faces a cyclohexane ring while in the trans structure the cyclohexane rings face one another.     

Crystal structure of Zn4Na(OH)6SO4Cl·6H2O

The structure of Zn₄Na(OH)₆SO₄Cl·6H₂O, a secondary mineral from Hettstedt, Germany, was determined by single-crystal X-ray diffraction. The crystals are hexagonal,a=8.413(8),c=13.095(24) Å, space group $P\bar 3$ , Z=2. The structure was refined to R=0.0554 and R_w=0.0903 for 970 reflections with I≥3σ(I). The structure can be described as zinc hydroxide layers perpendicular toc, from which sulfates and chlorides extend. The layers are held together by a system of hydrogen bonds involving hexaaquo Na⁺ ions which occupy the interlayer space.     

Synthesis and Crystal Structure of 5-[2-(6-bromonaphthalenyloxymethyl)]-3-(4-morpholinomethyl)-1,3,4-oxadiazole-2(3<Emphasis Type="Italic">H</Emphasis>)-thione

Abstract  The title compound, C₁₈H₁₈BrN₃O₃S, a derivative of 1,3,4-oxadiazole, crystallizes in the triclinic space group P-1 with unit cell parameters a = 6.8731(3), b = 8.9994(4), c = 15.7099(6) ?, α = 92.779(3)°, β = 130.575(3)°, γ = 107.868(4)°, Z = 2. The dihedral angle between the mean planes of the planar naphthyl and morpholine (chair) rings with the planar oxadiazol ring is 50.1(8) and 76.8(6)°, respectively. The planar naphthyl ring is twisted 52.2(5)° with the mean plane of the morpholine ring. A group of four intermolecular close contacts are observed between a bromine atom and hydrogen atoms from the closely packed naphthyl, morpholine and oxy–methyl groups in the unit cell. These molecular interactions in concert with an additional series of π–π stacking interactions that occur between the center of gravity of the two 6-membered rings of the naphthalene group influence the twist angles of each of these three groups. A MOPAC AM1 calculation of the conformation energy of the crystal structure [226.0128(9) kcal] compared to that of the minimum energy structure after geometry optimization [29.9744(1) kcal] reveals a significantly reduced value. The twist angles of the three groups above also change after the AM1 calculation giving support to the influence of both intermolecular C–H···Br short-range interactions and Cg π–π stacking interactions on these angles which therefore play a role in stabilizing crystal packing. Graphical Abstract  Crystal structure of 5-{[(6-bromonaphthalen-2-yl)oxy]methyl}-3-(morpholin-4-ylmethyl)-1,3,4-oxadiazole-2(3H)-thione, C₁₈H₁₈BrN₃O₃S, is reported and its geometric and packing parameters described and compared to a MOPAC computational calculation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

电沉积法制备ZnO纳米棒阵列及其发光特性

本文以掺F的SnO2导电玻璃为基板,以硝酸锌水溶液为电解液,采用三电极恒电位体系电沉积制备ZnO纳米棒阵列,系统考察了硝酸锌浓度和沉积电位等工艺参数对ZnO纳米棒阵列的微观形貌及其发光性能的影响规律.结果表明,硝酸锌浓度和沉积电位对纳米棒阵列的形貌有显著影响,控制适宜的工艺条件可以制备出直径分布均匀、结晶性好且纯度高的六方纤锌矿ZnO纳米棒阵列.荧光光谱分析表明,电沉积制备出的ZnO纳米棒阵列在385 nm附近有一个强荧光发射峰,且发光性能稳定、对纳米棒阵列微观形貌的细微变化不敏感,使其在发光二极管和激光器等领域具有广阔的应用前景.     

Crystal structure of irisolidone from the flowers of Pueraia lobata

Irisolidone (5,7-dihydroxy-6,4′-dimethoxyisoflavone) was isolated from the flowers of Pueraia lobata and its crystal structure was examined by X-ray single crystal diffraction. The crystal structure of irisolidone is monoclinic, space group P2₁/c with a = 15.491(9) ?, b = 7.895(4) ?, c = 13.321(7) ?, β = 110.546(9)° and Z = 4. Hydrogen bonding and aromatic π–π stacking assemble the title compound into a three-dimensional networking structure.