ZnO纳米颗粒团聚微球的生长机理研究

采用化学浴沉积法,以Zn(CH3COO)2和TEA为反应体系,制备了ZnO纳米颗粒团聚微球,并对不同陈化时间阶段下的产物分别进行了物相、形貌、热重以及傅里叶红外吸收光谱表征,同时研究了不同TEA含量对最终产物的影响.结果表明:在恒温陈化过程中,首先会生成纳米片状的Zn5(OH)8Ac2·2H2O,同时它们之间相互连接为花状结构.其次随着陈化时间的增加,花状的Zn5(OH)8Ac2·2H2O不断分解为ZnO纳米颗粒,最后ZnO纳米颗粒会进一步自组装为一定尺寸的微米球.     

TiO2/ZnO复合微球的制备及其光催化性能研究

以碳微球为模板,采用溶胶凝胶法、水热法等方法分别制备了TiO2微球、ZnO微球和TiO2/ZnO复合微球,采用扫描电子显微镜、X-射线衍射仪等对样品进行了表征,结果表明:制备的TiO2微球、ZnO微球和TiO2/ZnO复合微球,各微球直径在5 ～ 10 μm之间.在紫外光和可见光下研究了制备的光催化剂对亚甲基蓝溶液和湖水的光催化性能,光催化实验表明:三种微球中TiO2/ZnO复合微球具有良好的光催化性能.     

水热法制备ZnO/石墨烯复合材料及其电化学性能研究

采用水热法制备ZnO/石墨烯复合材料,研究了ZnO、石墨烯不同配比与其电化学性能的关系.通过X射线衍射(XRD)、扫描电镜(SEM)、恒电流充放电、循环伏安法和交流阻抗等测试方法对复合材料结构、形貌及电化学性能进行表征,并通过电池解扣结合SEM和EDS进一步研究电极充放电前后的形貌及组分变化.结果表明,ZnO与石墨烯质量比为1∶1时电化学性能最好,在50 mA/g电流密度下首次可逆比容量高达680 mAh/g,且循环100次之后仍保持相对最高.电池解扣分析证明电极材料在充放电过程中表面会产生微裂纹影响其电化学性能.     

PbS/CdS纳米晶共敏化ZnO纳米线太阳能电池的性能研究

以Zn (Ac)2·2H2O为原料在强碱性条件下合成一维结构的ZnO纳米线,SEM结果表明合成的纳米线尺寸、形貌、长径比均一;并以油胺为单一溶剂采用热注射法制备了形貌、尺寸均匀的PbS纳米晶;构建PbS纳米晶敏化ZnO纳米线基太阳能电池,同时为了改善电池的光电转换效率并构建了PbS/CdS纳米晶共敏化电池,并测试了电池的光电流密度-光电压(J-v)曲线以及Nyquist曲线图,结果表明PbS/CdS纳米晶共敏化电池性能明显优于单纯的PbS纳米晶敏化ZnO纳米线太阳能电池.     

衬底温度对MOCVD-ZnO薄膜特性的影响

利用金属有机物化学气相沉积(MOCVD)生长技术,制备本征ZnO薄膜,并研究薄膜的结构、形貌及光电等性能.结果表明:衬底温度对ZnO薄膜的微观结构、电学、光学及表面形貌等有显著影响.在衬底温度为180℃时获得电阻率为2.17×10-2Ω·cm.平均透过率为85;的低电阻、高透过率、结晶质量高、表面呈绒面结构的本征ZnO薄膜.对本征ZnO薄膜进一步掺杂和结构优化有望用于硅薄膜太阳能电池的前电极.     

垂直导电衬底的ZnO纳米片的制备及其染料敏化太阳电池的性能

介绍了二水乙酸锌/甲醇体系和硝酸锌/尿素体系制备垂直导电衬底的多孔ZnO纳米片、相应染料敏化太阳电池的性能以及制备垂直导电衬底ZnO纳米片体系的发展和现状.硝酸锌/尿素体系更易得到垂直导电衬底的多孔ZnO纳米片,而采用二水乙酸锌/甲醇体系,既可得到垂直导电衬底的多孔ZnO纳米片,也可得到由纳米片组成的多级结构微球.当前,硝酸锌/尿素体系制备的垂直导电衬底的ZnO纳米片的电池最高光电转换效率已达6.06;.     

表面活性剂辅助法制备纳米Z nO及光催化性能研究

以Zn(NO3)2·6H2 O、氨水和不同的表面活性剂为原料,采用沉淀法制备了具有不同微观形貌和尺寸的纳米ZnO,研究表面活性剂对纳米ZnO光催化降解甲基橙性能的影响.通过X射线衍射仪(XRD)、扫描电镜(SEM)和紫外可见分光光度计(UV-Vis)等对所制备纳米ZnO的物相、形貌及光吸收性能进行表征,并对其进行光催化性能测试.结果表明,以CTAB为表面活性剂所制备的纳米ZnO,粒径均匀、分散性良好、无明显团聚现象,并且对甲基橙的光催化降解性能最好,在2 h内降解率可达90.6;.     

ZnO/TiO2复合光阳极染料敏化太阳能电池的研究

采用醇热法制备ZnO纳米粉体,采用水热法制备TiO2纳米粉体,将不同质量分数的ZnO与TiO2混合制备浆料,采用刮涂法在掺氟的SnO2透明导电玻璃(FTO)上制备ZnO/TiO2纳米复合薄膜光阳极,与Pt对电极和电解质组装成染料敏化太阳能电池.采用X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)和扫描电镜(SEM)对所制备的样品进行表征,通过光电性能测试和电化学阻抗谱测试,研究了添加不同质量分数的ZnO对电池性能的影响.结果表明:不添加ZnO纳米粉时,纯TiO2光阳极的电池光电转换效率为7.95;,而添加了2wt; ZnO的ZnO/TiO2复合光阳极电池的效率达到9.54;,比纯TiO2电池的效率提高了20;.     

电沉积制备的ZnO薄膜在染料敏化太阳能电池中光电性能的研究

采用阴极电沉积法在导电玻璃基体上制备了ZnO薄膜,研究了工艺条件对ZnO薄膜在染料敏化太阳能电池(DSSC)中的光电性能的影响.通过热分析(TG-DTA),X射线衍射(XRD)和电子扫描电镜(SEM)对ZnO薄膜的结构和形貌进行了表征.实验结果表明,电沉积制备的ZnO薄膜为纤锌矿结构,薄膜颗粒均匀,在DSSC中表现出较好的光伏性能.     

溅射压强对低阻高透过率掺钛氧化锌透明导电薄膜的影响

利用直流磁控溅射法在室温水冷玻璃衬底上制备出了高质量的掺钛氧化锌透明导电薄膜(ZnO: Ti).研究了溅射压强对ZnO: Ti薄膜结构、形貌和光电性能的影响.研究结果表明,溅射压强对ZnO: Ti 薄膜的结构和电阻率有显著影响.X射线衍射(XRD)表明,ZnO: Ti 薄膜为六角纤锌矿结构的多晶薄膜,且具有c轴择优取向.在溅射压强为5.0 Pa时,实验获得的ZnO: Ti薄膜电阻率最小值为1.084 ×10~(-4) Ω· cm.实验制备的ZnO: Ti 薄膜具有良好的附着性能,可见光区平均透过率超过91;.ZnO: Ti薄膜可以用作薄膜太阳能电池和液晶显示器的透明电极.     

CsI-LiCl共晶材料的坩埚下降法生长与闪烁性能研究

本文采用坩埚下降法,在真空密封的石英坩埚中成功生长出CsI-LiCl与CsI-LiCl:Na共晶闪烁体。通过扫描电子显微镜(SEM)观察晶体微结构表明该共晶中LiCl相与CsI相存在周期性的层状排列,CsI相的厚度在5 μm左右。共晶样品的X射线激发发射谱显示在CsI-LiCl和CsI-LiCl:Na共晶样品存在缺陷发光,在CsI-LiCl样品中还观察到了纯CsI的自陷激子(STE)发光。CsI-LiCl样品在α粒子激发下的多道能谱中观察到明显的全能峰,这一结果证明CsI-LiCl共晶可用于热中子探测的潜力。     

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.     

静电纺丝法制备CeO2微纳米纤维及其除氟性能

以聚丙烯腈(PAN)为载体,六水合硝酸铈[Ce(NO₃)₃·6H₂O]为原料,采用静电纺丝法制备了Ce(NO₃)₃/PAN纤维,在空气中热处理得到CeO₂微纳米纤维,通过XRD、BET和SEM对CeO₂微纳米纤维进行表征。采用静态吸附实验探讨了CeO₂微纳米纤维去除水溶液中氟离子的性能,考察了溶液pH值、初始氟离子浓度及共存阴离子等对吸附性能的影响。结果表明,pH=3时,CeO₂微纳米纤维对F^-的吸附性能最佳,CeO₂吸附量随着F^-浓度的增大呈上升趋势。CeO₂微纳米纤维对F^-的吸附等温线遵循Langmuir模型,二级动力学模型能很好地描述CeO₂微纳米纤维对F^-的吸附过程。CeO₂微纳米纤维的除氟性能优良,可为其实际应用提供理论参考。     

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.     

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).     

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.     

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.