直流反应磁控溅射法制备ZnO: Zr透明导电薄膜

以Zn∶ Zr为靶材,利用直流反应磁控溅射法制备了ZnO∶ Zr透明导电薄薄膜.研究了沉积压强对ZnO∶ Zr薄膜形貌、结构、光学及电学性能的影响.实验结果表明所制备的ZnO∶ Zr为六方纤锌矿结构的多晶薄膜,具有垂直于衬底方向的c轴择优取向.沉积压强对ZnO∶ Zr薄膜的晶化程度、形貌、生长速率和电阻率影响很大,而对其光学性能如透光率、光学带隙及折射率影响不大.当沉积压强为2Pa时,ZnO∶ Zr薄膜的电阻率达到最小值2.0×10-3Ω ·cm,其可见光平均透过率和平均折射率分别为83.2％和1.97.     

衬底温度对直流磁控溅射法制备掺锆氧化锌透明导电薄膜性能的影响

利用直流磁控溅射法在石英衬底上制备出了高透明导电的掺锆氧化锌(ZnO:Zr)薄膜.研究了衬底温度对ZnO:Zr薄膜结构、形貌及光电性能的影响.XRD表明实验中制备的ZnO:Zr为六方纤锌矿结构的多晶薄膜,具有垂直于衬底方向的c轴择优取向.实验所制备ZnO:Zr薄膜的晶化程度和导电性能对衬底温度有很强的依赖性.当衬底温度为300 ℃时, ZnO:Zr薄膜具有最小电阻率7.58×10-4 Ω·cm,其可见光平均透过率超过了91;.     

溅射功率对钛镓共掺杂氧化锌透明导电薄膜光电性能的影响

以ZnO∶Ga2O3∶TiO2(97wt;∶1.5wt;∶1.5wt;)陶瓷靶作为溅射源,采用射频磁控溅射技术在玻璃衬底上制备了钛镓共掺杂氧化锌(TGZO)透明导电薄膜,通过X射线衍射仪、四探针仪和分光光度计测试表征,研究了溅射功率对TGZO薄膜晶体结构、电学性质和光学性能的影响.结果表明:所有TGZO薄膜均为六角纤锌矿结构,并且具有(002)择优取向,溅射功率对薄膜性能具有明显的影响.当溅射功率为200 W时,TGZO薄膜的结晶质量最好、电阻率最低、平均可见光透射率最高,品质因数最大(1.22×10-2 Ω-1),其光电综合性能最佳.另外,通过光谱拟合方法研究了溅射功率对TGZO薄膜折射率和消光系数的影响,并利用Tauc关系式计算了样品的光学能隙.     

靶与衬底之间的距离对ZnO∶Zr透明导电薄膜性能的影响

利用直流磁控溅射法在室温玻璃衬底上制备出了可见光透过率高、电阻率低的掺锆氧化锌(ZnO∶Zr)透明导电薄膜。并系统地研究了靶与衬底之间的距离对ZnO∶Zr薄膜结构、形貌、光学及电学性能的影响。实验结果表明,靶与衬底之间的距离对ZnO∶Zr薄膜的生长速率、结晶质量及电学性能有很大影响,而对其光学性能影响不大。实验制备的ZnO∶Zr为六方纤锌矿结构的多晶薄膜,且具有垂直于衬底方向的c轴择优取向。当靶与衬底之间的距离从60 mm减小到50 mm时,薄膜的晶化程度提高、晶粒尺寸增大,薄膜的电阻率减小;然而,当距离继续减小时,薄膜的晶化程度降低、晶粒尺寸减小,薄膜的电阻率增大。当靶与衬底之间的距离为50 mm时,薄膜的电阻率达到最小值4.2×10-4Ω.cm,其可见光透过率超过95%。实验制备的ZnO∶Zr薄膜可以用作薄膜太阳能电池和液晶显示器的透明电极。     

Ag掺杂ZnO薄膜结构和光学特性研究

采用脉冲激光沉积技术制备出了Ag掺杂的ZnO薄膜.研究了Ag含量、衬底温度及氧压对ZnO结构和光学性能的影响.结果表明:Ag以替位形式存在于ZnO晶格中,Ag掺杂浓度较低时,样品具有高度c轴择优取向.衬底温度越高,薄膜的结晶质量越好,光学带隙越接近纯ZnO的带隙,而其紫外荧光峰在衬底温度为300 ℃时最强.氧压为10 Pa时,薄膜的结晶质量最好,紫外峰最强,其带隙则随氧压的增大呈先变窄后加宽的趋势.     

Nb掺杂ZnO透明导电薄膜的结构以及光电性能研究

采用直流磁控溅射法在玻璃衬底上制备了高质量的Nb掺杂ZnO( NZO)透明导电薄膜.为了研究薄膜厚度对薄膜性质的影响,制备了五个厚度分别为239 nm,355 nm,489 nm,575 nm和679 nm的样品.XRD结果表明,ZnO∶ Nb薄膜是具有六角纤锌矿结构的多晶薄膜,并且具有垂直于衬底的c轴择优取向.随着膜厚的增加,薄膜的结晶质量明显提高.当厚度从239 nm增加到489 nm时,平均晶粒尺寸从19.7 nm增加到24.7 nm,薄膜的电阻率持续减小;当厚度进一步增加时,晶粒尺寸略有减小,电阻率有所增加.本实验获得的最低电阻率为4.896×10-4Ω·cm.随膜厚的增加,光学带隙先增大后减小.所有薄膜在可见光区域的平均透过率均超过88.3;.     

溅射功率对ZnO∶Si透明导电薄膜性能的影响

采用直流磁控溅射法在室温玻璃基片上制备出了掺硅氧化锌(ZnO∶ Si)透明导电薄膜.研究了溅射功率对ZnO∶ Si薄膜结构、形貌、光学及电学性能的影响.结果表明,溅射功率对ZnO∶ Si薄膜的生长速率、结晶质量及电学性能有很大影响,而对其光学性能影响不大.实验制备的ZnO∶Si薄膜为六方纤锌矿结构的多晶薄膜,且具有垂直于基片方向的c轴择优取向.当溅射功率从45 W增加到105 W时,薄膜的晶化程度提高、晶粒尺寸增大,薄膜的电阻率减小;当溅射功率为105 W时,薄膜的电阻率达到最小值3.83×10-4 Ω·cm,其可见光透过率为94.41;.实验制备的ZnO∶ Si薄膜可以用作薄膜太阳能电池和液晶显示器的透明电极.     

膜厚对Zr,Al共掺杂ZnO透明导电薄膜结构和光电性能的影响

采用直流磁控溅射法在玻璃衬底上制备出Zr,Al共掺杂ZnO(AZZO)透明导电薄膜.用XRD和SEM分析和观察了薄膜样品的组织结构和表面形貌.研究表明:制备的AZZO透明导电薄膜为六角纤锌矿结构的多晶薄膜,且具有c轴择优取向.另外还研究了薄膜的结构、光学和电学性质随薄膜厚度的变化关系.当薄膜厚度为843 nm时,电阻率具有最小值1.18×10~(-3) Ω·cm,在可见光区(500～800 nm)平均透过率超过93;.     

基于柔性玻璃衬底ZnO∶B薄膜的非晶硅太阳能电池的制备及其光电性能研究

采用低压化学气相沉积法(LPCVD)在大面积(40 cm ×40 cm)超薄柔性玻璃和硬质玻璃衬底上分别制备了B掺杂的ZnO(BZO)透明导电薄膜及非晶硅薄膜太阳能电池,对比了两种衬底上BZO薄膜的形貌、光学和导电性能及其非晶硅薄膜电池的性能.结果表明,在相同LPCVD工艺下,超薄柔性玻璃衬底上BZO薄膜的生长速率相对减小;当生长相同厚度BZO薄膜时,超薄柔性玻璃衬底的透光率相对于硬质玻璃衬底提高约2;,同时并具有相同的导电能力.在柔性玻璃衬底上制备的非晶硅薄膜电池的初始和稳定转化效率也相对提高,分别达到9.16;和7.82;.     

衬底温度对氢化非晶硅薄膜特性的影响

采用等离子增强化学气相沉积(PECVD)系统,以乙硅烷和氢气为气源,石英玻璃和单晶硅片为衬底制备了氢化非晶硅(a-Si∶ H)薄膜.采用扫描电子显微镜、X-射线衍射仪、台阶仪、紫外可见分光光度计、傅里叶变换红外光谱仪和电子能谱仪等分别表征了a-Si∶H薄膜的表面形貌、结晶特性、沉积速率,光学带隙,键合结构和Si化合态等特性.结果表明:随着衬底温度的增加,a-Si∶H薄膜表面的颗粒尺寸减小,均匀性增加,沉积速率则逐渐降低;衬底温度从80℃增加到130℃时,光学带隙显著增加,而在130℃至230℃范围内,光学带隙基本不随衬底温度变化;以SiH键对应的伸缩振动的相对峰强度逐渐增加,而以SiH2或(SiH2)n键对应的伸缩振动的相对强度逐渐减小;a-Si∶H薄膜中Si0+态的相对含量增加.因此,衬底温度大于130℃有利于制备优质a-Si∶H薄膜,230℃是沉积a-Si∶H薄膜的最佳衬底温度.     

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。     

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。     

Selinidin: Crystal structure generated by C–H···O, C–H···π and π-π interactions

The title compound, 9,10-dihydro-8,8-dimethyl-2-oxo-2H,8H-benzo[1,2-b:3,4-b']dipyran-9-yl-2-methyl-2-butenoate, C₁₉H₂₀O₅, was isolated from the roots of Selinum vaginatum. The compound crystallizes into monoclinic space group P2 ₁ with unit cell parameters: a = 12.830(2) Å, b = 9.041(1) Å, c = 14.983(1) Å, β = 95.09(1)°, Z = 4. The crystal structure has been determined using direct methods and refined by full-matrix least-squares to a final R value of 0.0529 for 3142 observed reflections. There are two independent molecules, A and B, per asymmetric unit. In both the molecules, the coumarin nucleus is planar. However pronounced differences are observed in the conformation of dihydropyran ring which has a half-chair conformation with an 8β-9α orientation in molecule A and is intermediate between half-chair and sofa in molecule B. Differences also occur in the conformation of the 2-methylbutenoyloxy side chain at C9 due to the different geometry of C–H···π interactions in molecules A and B. Molecules A and B are connected by π–π interactions between their coumarin fragments forming dimers. The dimers interact through C–H···O and C–H···πhydrogen bonds.     

Chromene and Imidazole Based D-π-A Chemosensor Preparation and Its Anion Responsive Effects

We have designed and synthesized the colorimetric chemosensor through the reactions of 2-(4H-chromen-4-yildene)malonitrile and 4-imidazolecarboxaldehyde. Due to its well conjugated D-π-A system and the existence of NH- fragment in structure, we expected that the chemosensor can detect anion using NH- fragment in the imidazole moiety of the structure. In this regard, UV-Vis absorption spectra were measured to investigate sensing properties of the probe toward different anions in DMSO. This chemosensor can detect both fluoride and cyanide ion with absorption change in intensity. In addition, pH sensing property was also investigated upon the addition of hydroxide ion. These properties are related to the deprotonation effect. The ICT system in this molecule was also observed by the computational approach using Material Studio 4.3 package.     

电子显微分析在表征纳米晶体化学组分中的应用

纳米材料的化学组分及含量影响其光、电、声、热、磁等物理性能,电子显微分析是表征纳米晶体化学组分的重要方法之一.本文综述了X-射线能谱(EDS)、X-射线波谱(WDS)、电子能量损失谱(EELS)和选区电子衍射(SAED)等现代电子显微分析技术在表征纳米晶体化学组分、形貌、尺寸和结构等方面的应用及其研究进展,并比较了这些分析方法存在的差异,提出了其应用中存在的不足及今后的研发方向.     

4- and 5-nitroindane

Mononitration of indane produces a mixture of 4- and 5- nitroindanes. Crystallization from mixtures occurs after distillation improves composition of a major component to above 80%. 4-Nitroindane: triclinic, space group (#2),a=7.332(4) Å,b=8.304(4) Å,c=8.358(4) Å, =61.43(4)°, =67.60(4)°, =70.15(4)°,V=405.4(4) ų,Z=2. Non-H-atoms are nearly planar, aliphatic H's are eclipsed. 5-Nitroindane: monoclinic, space groupP2₁/c (#14),a=10.946(8) Å,b=15.643(10) Å,c=9.415(6) Å, =92.34(5)°,V=1611(2) ų,Z=8. Non-H-atoms in the two molecules differ in torsion of the nitro group with respect to indane and fold of the nonbenzylic methylene group. Semiempirical calculations (PM3) suggest that distorsion from planarity may be associated with the two lowest energy vibrational modes. Uv, ir, ms, proton, and¹³C-nmr spectra are correlated with the solid state structures.     

6<Emphasis Type="Italic">S</Emphasis>,8α-Dihydroxy-14,15-Dihydrocarapin (Khayanone) from the Stem Bark of <Emphasis Type="Italic">Khaya Senegalensis</Emphasis> (Meliaceae): Isolation and its Crystal Structure

Khayanone was isolated from the stem bark of African mahogany, Khaya senegalensis (Meliaceae), and characterized as 6S,8α-dihydroxy-14,15-dihydrocarapin on the basis of spectral analysis and single crystal X-ray diffraction study. The compound crystallizes in the tetragonal space group P4 ₁ 2 ₁ 2 with unit cell parameters: a = 13.2315(19) Å, c = 29.118(6) Å, Z = 8. The crystal structure has been solved by direct methods and refined to R = 0.0375 for 4552 unique reflections. The six-membered rings A and B exist in boat conformations, rings C and D in chair conformations, and the furan ring is planar. The crystal structure is stabilized by O-H···O and C-H···O interactions. This is the first report about 6S configuration of mexicanolide revealed by X-ray diffraction analysis. The configuration of oxygenated C-6 in mexicanolide-group limonoids is discussed.     

Nuclear magnetic resonance: a powerful tool to study liquid crystals

Nuclear magnetic resonance (NMR) is a spectroscopic technique widely used to investigate materials and soft matter in particular. In this brief review, the main uses of NMR techniques to investigate different aspects of liquid crystals, such as the orientational and dynamic properties, the supramolecular structure and average molecular conformations, are described. In the second part of the paper, the case study of a ‘de Vries’ liquid crystal is reported and the main results obtained by combining different NMR techniques are discussed.     

X-ray analysis of sideroxol from <Emphasis Type="Italic">Sideritis leptoclada</Emphasis>

Sideroxol (1), a kaurane diterpene which has the ent-7α,18-dihydroxy-15β,16β-epoxykaurane structure (MW = 320.47, C₂₀H₃₂O₃) was obtained from the acetone extract of Sideritis leptoclada plant as well as from some other Sideritis species. It crystallizes in the orthorhombic space group P2₁, 2₁, 2₁ with a = 10.967(3), b = 24.555(5), c = 6.372(4) Å, Dc = 1.240 g cm⁻³, Z = 4, and refines to R = 0.065 for 721 independent reflections. The skeleton consists of three fused six-membered rings and a five-membered ring with fused epoxide. The six membered rings exhibited slightly distorted chair conformation. In addition to sideroxol, two kaurane and five kaurene diterpenes were isolated from the hexane and acetone extracts of the studied plant.     

New zeotype borophosphates with chiral tetrahedral topology: (H)0.5M1.25(H2O)1.5[BP2O8]·H2O (M = Co(II) and Mn(II))

Two new isostructural open‐framework zeotype transition metal borophosphate compounds, (H)_0.5M_1.25(H₂O)_1.5[BP₂O₈]·H₂O (M = Co(II) and Mn(II)) were synthesized by mild hydrothermal method. The structure of compounds were characterized by single‐crystal X‐ray diffraction which have ordered, alternating, vertex‐sharing BO₄, PO₄, and (MO₄)OM(H₂O)₂ groups with hexagonal, P 6₁ 2 2 (No 178) space group and unit cell parameters for Co a = 9.4960(6) Å, c = 15.6230(13) Å, for Mn a = 9.6547(12) Å, c = 15.791(3) Å, Z = 1 for both of them. TGA/DTA analysis, IR spectroscopy were used for characterization. Magnetic susceptibility measurements for both of the compound indicate strong antiferromagnetic interaction between metal centers. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)