前驱液成分对TFA-MOD法制备YBa2Cu3O7-x薄膜超导性能的影响

采用三氟乙酸盐-金属有机沉积法(TFA-MOD)在铝酸镧单晶基体上制备了YBa₂Cu₃O_7-x (YBCO)超导薄膜.通过改变前驱液的成分,研究了金属元素的不同化学计量比对YBCO薄膜的结构和性能的影响.结果表明,按照钇盐Y(CH₃COO)₃与钡盐Ba(CH₃COO)₂的比例为Y ∶Ba=1 ∶1.5时所制备的YBCO薄膜的临界电流密度比严 关键词： 三氟乙酸盐-金属有机沉积 钇钡铜氧薄膜 前驱液成分 磁通钉扎     

邻巯基氧化吡啶双齿配位的钴化合物的1H NMR研究

对四种单核钴化合物Co(mpo)₃·CH₃CN(Ⅰ),CO(mpo)₂PBu₃(D),Co(mpo)₂Py(Ⅲ)和Co(mpo)₂Py₂(Ⅳ)的¹H NMR作了研究,讨论了它们的分子结构与磁性及电子结构之间的关系,确认化合物(Ⅱ)在DMSO溶液中被解离为Co(mpo)₂和PBu₃,而其它三种化合物仍保留着固态结构。     

一组Dawson型多金属氧酸盐和相应的有机-无机杂多化合物的超快非线性光学响应(英文)

通过时间分辨率为115fs的超快光克尔方法测量了多金属氧酸盐K₈[P₂Mo₄W₁₃M（H₂O）O₆₁]（M=Mn,Co,Ni,Cu,Zn）和相应的有机-无机杂多化合物(C₁₉H₂₅N₂)₇K₃[P₂Mo₄W₁₃MO₆₂]在830 nm处的三阶非线性光学性质.多金属氧酸盐阴离子和相应的杂多化合物都表现出很大的三阶非线性,其中M=Cu的取代物的非线性系数要比其他小一个数量级.通过比较有机-无机杂多化合物和生成前者的反应物的γ值,发现杂多化合物中的电荷转移效应极大的增强了三阶非线性光学性能.     

一些含桥羧基配体的羰基钼(Ⅰ)化合物的NMR研究

化合物(1)[(CO)₄Mo(SPh)₂Mo(CO)₄]同羧酸L反应得到桥羧基配体的羰基钼(Ⅰ)化合物[Bu₄N][(CO)₃Mo(SPh)₂LMo(CO₃)](L=CF₃COO,HCOO,CH₃COO,C₂H₅COO,OOCCH₂CH₂COO,Me₃COO),在室温下测定了它们的¹H,¹³C,⁹⁵MoNMR谱,由于配位基团、对称性及Mo-Mo键长等结构的变化,两者的谱线差别很大,特别是⁹⁵MoNMR更为敏感,即使是不同的羧基也会影响它的化学位移和线宽,其屏蔽和线宽的顺序是Me₃COO^-1 > C₂H₅COO^-1 > CH₃COO^-1 > HCOO^-1 > F3COO^-1。     

SiC外延层表面化学态的研究

用高分辨X射线光电子能谱仪(XPS)和傅里叶变换红外(FTIR)光谱仪研究了SiC外延层表面的组分结构. XPS宽扫描谱,红外掠反射吸收谱及红外镜面反射谱的解析结果说明SiC外延层表面是由Si—O—Si和Si—CH₂—Si聚合体构成的非晶SiC_xO_y:H. SiC外延层表面的化学态结构为Si(CH₂)₄,SiO(CH₂)₃,SiO₂(CH₃)₂,SiO₃(CH₃),Si—Si,游离H₂O,缔合OH,Si—OH,O和O₂. 根据化学态结构和元素电负性确定了化学态的各原子芯电子束缚能顺序,并与XPS窄扫描谱拟合结果相对比,建立了化学态与其束缚能的对应关系,进而用Si(CH₂)₄的实际C 1s束缚能值进行校正,确定了各化学态的束缚能. 结果发现,除了SiC_xO_y(x=1,2,3,4,x+y=4)的Si 2p束缚能彼此不同外,其C 1s和O 1s彼此也不相同,其中SiO₂(CH₃)₂和SiO₃(CH₃)的C 1s束缚能与CH_m和C—O中C 1s的相近,对此从化学态结构,元素电负性和邻位效应进行了解释. 关键词： SiC 化学态 XPS FTIR     

非晶钛酸锶钡薄膜的金属有机分解法制备及其光学性能

本文采用2-辛酸钡(Ba(C₈H₁₅O₂)₂)和3-甲基丁基醋酸盐(CH₃COOC₂H₄CH(CH₃)₂-)为基的特殊前驱体溶液,在硅和石英基片上低温制备Ba_0.7Sr_0.3TiO₃ (BST0.7)薄膜.性能测试结果表明,厚度约为214 nm的非晶BST0.7薄膜的光学带隙能和折射率分别为4.27 eV和n=1.94.薄膜在可见光和近红外区域的消光系数远远低于多晶BST薄膜,约为10^-3数量级.激发波长为450 nm时,在室温环境下非晶BST0.7薄膜在波长520—610 nm处发出强烈的可见光,峰值为540—570 nm,而结晶态的BST0.7薄膜则无发光现象. 关键词： 钛酸锶钡 非晶薄膜 金属有机分解法 光学性能     

4种联咪唑衍生物的铜配合物的合成、表征及与ct-DNA相互作用的光谱研究

合成并表征了N,N’-二甲基-5-硝基-2,2’-联咪唑分别与铜盐Cu（Ac）₂·H₂O、CuBr₂、CuCl₂·2H_O和CuSO₄·2H₂O所形成的4种配合物。利用紫外光谱、荧光光谱和粘度等方法研究了配合物与DNA的作用,结果表明配合物均以部分插入模式与DNA相互作用。     

二己二硫醚多层膜局域结构的近边x射线吸收精细结构研究

利用多重散射团簇(MSC)方法计算了二己二硫醚［CH₃(CH₂)₅S］₂单分子和多分子硫原子近边x射线吸收精细结构(NEXAFS)谱，给出了二己二硫醚多层膜的局域结构模型. MSC研究显示多层膜中二己二硫醚分子作平行有序排列，彼此相距0.47nm，其横截面呈规则的正方形. 利用离散变分Xα方法计算了二己二硫醚单分子和多分子的电子结构，验证了MSC的计算结果；并阐明了NEXAFS谱中各峰的物理起源. 对多层膜中分子之间的相互作用进行了讨论，发现多层膜的局域结构有分子自组装的特性. 关键词： 3(CH₂)₅S］₂多层膜')" href="#">二己二硫醚［CH₃(CH₂)₅S］₂多层膜 近边x射线吸收精细结构 多重散射团簇方法 离散变分Xα方法     

有机-无机杂化钙钛矿自组装量子阱结构的能带调控和光电性能的研究

有机-无机杂化钙钛矿材料具有分子尺度上调节能带结构的特点,在光、电、磁等领域均表现出了优异的性能.通过简单的旋涂方法,成功的制备了具有不同无机层层数的杂化钙钛矿材料(C₆H₁₃NH₃)₂(CH₃NH₃)_n-1Pb_nI_3n+1 (简写为C₆Pb关键词： 杂化钙钛矿 量子阱 带隙 光电性能     

用1H NMR法研究[Co (Xacac)2(Me-en)]ClO4的重氢化

应用¹H NMR技术推定了新合成的二(3-取代X基-2,4-戊二酮).N-甲基乙二胺合钴(Ⅲ)配合物:[Co (Xacac)₂(Me-en)]ClO₄(X=CH₃、Cl、NO₂)的△(R)∧(S)和△(S)∧(R)异构体的空间构型,测定了各配合物异构体手性配位氮原子上的重氢化速率常数k_D值(34.0℃).结果表明,取代基X对k_D值有着显著影响。     

Transient resonance Raman spectroscopy and DFT calculations of metal‐to‐ligand charge transfer states of Cu(I) complexes of substituted 1,10‐phenanthroline ligands and their perdeuterated isotopomers

Cu(I) complexes of the type [Cu(L)(PPh₃)₂]⁺, where L is the bidentate ligand 4,7‐diphenyl‐1, 10‐phenanthroline (dip) and 3,4,7,8‐tetramethyl‐1,10‐phenanthroline (tem) and their perdeuterated analogues, have been synthesised and the transient resonance Raman spectra of these complexes have been measured. The spectra show two sets of bands, one due to the PPh₃ ligands and the other due to L^.− created through the metal‐to‐ligand charge transfer transition. Density functional theory calculations have been used to model ligands and complexes in the ground state and good agreement has been found between calculated and measured bands with a mean absolute deviation of 8–10 cm⁻¹ for the ligands and 5 cm⁻¹ for the complexes. Shifts in the bands due to deuteration have also been well predicted, with the shifts for most modes predicted to within 10 cm⁻¹. The structure and spectra of the excited states have been modelled using two approaches. The reduced state [Cu(L^.−)(PH₃)₂] was used for both complexes to predict the changes in the structure of the polypyridyl ligand and for [Cu(dip)(PPh₃)₂]⁺ the triplet state was also optimised. Both approaches show that similar structural changes in the ligand are predicted. In the case of [Cu(dip)(PPh₃)₂]^+* and [Cu(dip^.−)(PPh₃)₂], the calculated states are ³A₂ and ²A₂, respectively, consistent with experiment. Calculations on [Cu(tem)(PPh₃)₂]^+* give a ³B₁ state. This is not consistent with experimental results. For [Cu(tem^.−)(PPh₃)₂] both the ²B₁ and ²A₂ states may be calculated and the experimental spectrum of [Cu(tem)(PPh₃)₂]^+* is closer to that of the ²A₂ [Cu(tem^.−)(PPh₃)₂] species. Calculated wavenumbers are compared to measured transient resonance Raman L^.− bands and found to have a mean absolute deviation of 8 cm⁻¹ for the triplet state of [Cu(dip)(PPh₃)₂]⁺ and 16 cm⁻¹ for the reduced state of [Cu(tem)(PPh₃)₂]⁺. Copyright © 2008 John Wiley & Sons, Ltd.     

A comprehensive study of (CH3)2CHOC(S)SC(O)OCH3 using matrix isolation technique,X‐ray analysis,spectroscopic studies and theoretical calculations

Potassium isopropyl xanthate, (CH₃)₂CHOC(S)SK, reacts with methyl chloroformiate ClC(O)OCH₃ to yield (methoxycarbonyl) (2‐propoxythiocarbonyl) sulfide, (CH₃)₂CHOC(S)SC(O)OCH₃. This novel xanthogen formate was characterized by ¹H and ¹³C{¹H} NMR spectroscopy, mass spectrometry and IR and Raman spectroscopy. The structure of a single crystal of (CH₃)₂CHOC(S)SC(O)OCH₃ was determined by X‐ray diffraction analysis at 173 K. The conformational properties have been studied by liquid IR and Raman spectroscopy, matrix isolation spectroscopy together with photochemical studies and quantum chemical calculations (HF and B3LYP methods with the 6‐31+G* basis set). The analysis of the IR spectrum of liquid (CH₃)₂CHOC(S)SC(O)OCH₃ suggests the presence of two conformers in equilibrium at room temperature. However, in the photochemical matrix study, an equilibrium of three conformers was detected. These forms were further characterized by theoretical calculations. Different photolysis products, such as CH₃OC(O)SCH(CH₃)₂, OCS, CO, CO₂ and CS₂, were identified by matrix spectroscopy. The IR absorptions of CH₃OC(O)SCH(CH₃)₂, for which literature data are scarce, were analysed in the light of the results of appropriate theoretical calculations. Copyright © 2009 John Wiley & Sons, Ltd.     

低温超薄高效Cu(In,Ga)Se2太阳电池的实现

衬底温度保持恒定, 在Se气氛下按照一定的元素配比顺序蒸发Ga, In, Cu制备厚度约为0.7 μrm的Cu(In_0.7Ga_0.3)Se₂ (CIGS)薄膜. 利用X射线衍射仪分析薄膜的晶体结构及物相组成, 扫描电子显微镜表征薄膜形貌及结晶质量, 二次离子质谱仪测试薄膜内部元素分布, 拉曼散射谱 分析薄膜表面构成, 带积分球附件的分光光度计测量薄膜光学性能. 研究发现在Ga-In-Se预制层内, In主要通过晶界扩散引起Ga/(Ga+In)分布均匀化. 衬底温度高于450 ℃时, 薄膜呈现单一的Cu(In_0.7Ga_0.3)Se₂相; 低于400℃, 薄膜存在严重的Ga的两相分离现象, 且高含Ga相主要存在于薄膜的上下表面; 低于300 ℃, 薄膜结晶质量进一步恶化. 薄膜表层的高含Ga相Cu(In_0.5Ga_0.5)Se₂以小晶粒形式均匀分布于薄膜表面, 增加了薄膜的粗糙度, 在电池内形成陷光结构, 提高了超薄电池对光的吸收. 加上带隙值较小的低含Ga相的存在, 使电池短路电流密度得到较大改善. 衬底温度在550 ℃–350 ℃变化时, 短路电流密度J_SC是影响超薄电池转换效率的主要因素; 而衬底温度T_sub低于300 ℃时, 开路电压V_OC和填充因子FF降低已成为电池性能减退的主要原因. T_sub为350 ℃时制备的0.7 μm左右的超薄CIGS电池转换效率达到了10.3%. 关键词： 2薄膜')" href="#">Cu(In,Ga)Se₂薄膜 衬底温度 超薄 太阳电池     

Failure behavior of ITO diffusion barrier between electroplating Cu and Si substrate annealed in a low vacuum

A structure of Cu/ITO(10 nm)/Si was first formed and then annealed at various temperatures for 5 min in a rapid thermal annealing furnace under 10⁻² Torr pressure. In Cu/ITO(10 nm)/Si structure, the ITO(10 nm) film was coated on Si substrate by sputtering process and the Cu film was deposited on ITO film by electroplating technique. The various Cu/ITO(10 nm)/Si samples were characterized by a four-point probe, a scanning electron microscope, an X-ray diffractometer, and a transmission electron microscope. The results showed that when the annealing temperature increases near 600 °C the interface between Cu and ITO becomes unstable, and the Cu₃Si particles begin to form; and when the annealing temperature increases to 650 °C, a good many of Cu₃Si particles about 1 μm in size form and the sheet resistance of Cu/ITO(10 nm)/Si structure largely increases.     

Influence of crystallization on the spectral features of nano-sized ferroelectric barium strontium titanate (Ba0.7Sr0.3Tio3) thin films

Ferroelectric barium strontium titanate (Ba_0.7Sr_0.3TiO₃)(BST) thin films have been prepared from barium 2-ethylhexanoate [Ba[CH₃(CH₂)₃CH(C₂H₅)CO₂]₂]_, strontium 2-ethylhexanoate [Sr[CH₃(CH₂)₃CH(C₂H₅)CO₂]₂] and titanium(IV) isopropoxide [TiOCH(CH₃)₂]₄ precursors using a modified sol-gel technique. The precursor except [TiOCH(CH₃)₂]₄ were synthesized in the laboratory. Transparent and crack-free films were fabricated on pre-cleaned quartz substrates by spin coating. The structural and optical properties of films annealed at different temperatures have been investigated. The as-fired films were found to be amorphous that crystallized to the tetragonal phase after annealing at 550 °C for 1 h in air. The lattice constants “a” and “c” were found to be 3.974 A and 3.990 A, respectively. The grain sizes of the films annealed at 450, 500 and 550 °C were found to be 30.8, 36.0 and 39.8 nm respectively. The amorphous film showed very high transparency (∼95%), which decreases slightly after crystallization (∼90%). The band gap and refractive index of the amorphous and crystalline films were estimated. The optical dispersion data are also analyzed in the light of the single oscillator model and are discussed.     

Lamellar phenylene-bridged hybrid silicones

The acid-hydrolysis of a bismethyldiethoxysilylated para-phenylene-bridged derivative, (EtO)₂MeSi(CH₂)₃NHCONH(C₆H₄)NHCONH(CH₂)₃SiMe(OEt)₂, with urea groups has been performed in pure aqueous medium. The scanning electron microscopy (SEM) analysis of the resulting insoluble solid revealed plate-like forms. A lamellar structure was determined from the powder X-ray diffraction (PXRD) studies with a sharp peak at 21.1 Å. The solid state CP-MAS NMR spectra (²⁹Si and ¹³C) of the bridged siloxane hybrid exhibit a moderately condensed material with complete preservation of the Si–C bonds throughout the hybrid network.     

Quantum chemical study of the (Z)-2-penten-1-ol (HOCH2–CH = CHCH2CH3) + OH + O2 reactions

ABSTRACT

The mechanism and products of the reaction of (Z)-2-penten-1-ol [(Z)-PO21] with OH radical in the presence of O₂ have been elucidated by using high-level quantum chemical methods CCSD(T)/6-311+G(d,p)//BH&;HLYP/6-311++G(d,p). The calculations clearly indicate that addition channels contribute maximum to the total reaction and H-abstraction channels can be neglected at temperatures of 220–500 K. The rate constant for the reaction of OH radical with (Z)-PO21 at 298 K is computed to be 1.22 × 10^?10 cm³ molecule^?1 s^?1, which is in stronger agreement with the previously reported experimental values. The kinetic data obtained over the temperature range 220?500 K are used to derive an non-Arrhenius expression: k = 3.69 × 10^?13 × exp(1763.7/T) cm³ molecule^?1 s^?1. For the reaction of (Z)-PO21with OH radical in the presence of O₂, the major primary reaction products found in this study are propanal [CH₃CH₂C(O)H] and glycolaldehyde [HOCH₂C(O)H], whereas formaldehyde [HC(O)H], 2-hydroxybutanal [CH₃CH₂CH(OH)C(O)H] and the epoxide P18 are anticipated to be minor products. The calculated results are consistent with the recent experimental observations.     

低密度Cu掺杂SiO_2复合气凝胶的制备及表征

分别以正硅酸甲酯、醋酸铜为硅源和铜源,通过溶胶凝胶法及CO2超临界干燥技术制备了一系列Cu掺杂SiO2复合气凝胶。采用红外谱仪(FTIR)、扫描电镜(SEM)、X射线能谱仪(EDS)、比表面积和孔隙度分析仪(BET)、动态热机械分析仪(DMA)对样品进行了表征。结果表明随着铜含量的增加,复合气凝胶密度增加,比表面积降低,平均孔径增加,实际掺杂比与理论掺杂比对应增加。该复合气凝胶具有三维网状结构,密度低(40mg/cm3),比表面积高(390m2/g),成型性较好,有望应用于惯性约束聚变(ICF)实验。     

The time evolution of the sol-gel process:29Si NMR study of the hydrolysis and condensation reactions of tetraethoxysilane

The structure and properties of the glass products prepared by the sol-gel process are strongly dependent on the experimental conditions of their preparation. The time dependence of the structural intermediate formation obtained during hydrolysis and condensation reactions in tetraethoxysilane, ethanol, H₂O, HCl (molar ratio 1:3:1.5:0.01) sol-gel reaction mixture was investigated with²⁹Si nuclear magnetic resonance spectroscopy at −75°C. It is clear that the substitution of the Si ethoxy group (OCH₂CH₃) by a hydroxyl (OH) shifts the resonance lines downfield. The dimer peaks are located about 9–10 ppm upfield from the corresponding monomers, and Si located in the middle of the trimers appeared at the chemical shift of 18–19 ppm from the corresponding monomers. The peaks of cyclic trimers, cyclic tetramers and the other higher oligomers are relatively broad and weak and exhibit a multiplet structure. The time dependence of the concentrations of the individual types of silicon in the reaction mixture was evaluated from the integral intensity of the corresponding Si atoms from the²⁹Si NMR spectra. The results obtained represent an input data to the various kinetic models of the complicated hydrolysis and condensation reactions.     

The Vibrational Spectra of Complexes with Planar Monothiooxamides. IV. The Copper(II) and Copper(I) Complexes of Neutral Monothiooxamides

The new complexes CuX₂(LH₂), CuX₂ (SH₃) (X = Cl, Br), CuX(LH₂), CuX(SH₃) (X = Cl, Br, I), CuX(H₄MTO)₂ (X = Cl, Br), Cul(H₄MTO) and CuX(H₃MMTO)₂ (X = Cl, Br, I), where LH₂ = N.N′-dimethyl-monothiooxamide, SH₃ = N(s)-methylmonothiooxamide, H₄MTO = monothiooxamide and H₃MMTO = N_(o)-methylmonothiooxamide, have been prepared. The complexes were characterized by elemental analyses, conductivity measurements, magnetic moments and spectroscopic (UV/VIS, FT-IR, Laser-Raman) studies. The vibrational analysis of the complexes has been given using NH/ND, CH₃/CD₃ and ⁶³cu/⁶⁵cu isotopic substitutions. The neutral monothiooxamides behave as monodentate ligands in the Cu(I) complexes coordinating through their thioamide sulfur atom. The ligands LH2 and SH₃ act as bidentate chelating agents in the Cu(II) complexes with ligated atoms being the thioamide sulfur and the amide oxygen.