Gas-Sensitive Properties of SnO2-Based Thin Films Obtained from Film-Forming Solutions

Gas-sensitive properties of SnO₂ thin-film materials doped with antimony(III) with respect to the reducing gases CO, CH₄, and H₂ were studied. The materials were obtained from film-forming solutions of Sn(II) and Sb(III) complexes with acetylacetone.     

Physicochemical Properties of Polyaniline Base and Salt Films

Abstract

Polyaniline base and perchlorate salt films cast from N-methylpyr-rolidinone (NMP) solutions are studied using thermogravimetric analysis, infrared and ultraviolet-visible absorption spectroscopy, and x-ray photoelectron spectroscopy. Both types of films retain a substantial amount of solvent. Although most of the solvent can be removed by washing the films with deionized water, some C1O^? ₄ anions are removed from the salt films as well, resulting in a decrease in conductivity. In the salt films, protonation of the amine units in addition to the imine units can be readily achieved using HC1O₄. Structural modifications of the base films are apparent after one reprotonation/deprotonation cycle. These result in a decrease in the solubility of the film, the extent of which increases with the protonation level. Although NMP is a useful solvent for casting polyaniline salt and base films, both leucoemeraldine and perchloric acid protonated salt undergo degradation in this solvent.     

咪唑醋酸盐的制备和物理化学性质及其水和乙醇溶液的电导率

制备了离子液体1-甲基咪唑醋酸盐（[Mim]Ac）,1,3-二甲基咪唑醋酸盐（[Mmim]Ac）和1-乙基-3-甲基咪唑醋酸盐（[Emim]Ac）,分别测定了它们在293.15-338.14 K间的密度、电导率和绝对粘度,计算了相应的摩尔电导率和运动粘度.用最小二乘法分别拟合建立了密度、电导率、摩尔电导率、绝对粘度和运动粘度与温度的函数关系.讨论了咪唑环3位氮原子上烷基链长对以上咪唑醋酸盐五种物理化学性质的影响.在293.15 K测定了[Mim]Ac{或[Mmim]Ac,[Emim]Ac}（1）-H₂O（或EtOH）（2）二元溶液在全浓度范围内的电导导率,计算了对应的咪唑醋酸盐的摩尔电导率.发现无论是水溶液还是乙醇溶液,溶液的电导率和咪唑醋酸盐的摩尔电导率都随着浓度的增加先增大而后减小.同一浓度下,咪唑环3位氮原子上烷基链长增加,相应的溶液电导率和摩尔电导率下降.且水溶液的电导率和摩尔电导率远大于乙醇溶液的.     

Tunable Optical and Multiferroic Properties of Zirconium and Dysprosium Substituted Bismuth Ferrite Thin Films

This work presents optical and multiferroic properties of bismuth ferrite thin films that are affected by zirconium and dysprosium substitution. Non-centrosymmetric BiFeO₃,Bi_0.95Zr_0.05FeO₃, and Bi_0.95Dy_0.05FeO₃ thin films were coated on Pt/TiO₂/SiO₂/Si substrates using the spin coating method. The crystal structure, optical properties, microstructural, ferromagnetic, and ferroelectric properties of doped bismuth ferrite thin films were systematically investigated. From the XRD patterns, all the prepared thin films matched well with the rhombohedral structure with R3c space group with no observed impurity phases. The average crystallite size of the bismuth ferrite thin films were between 35 and 47 nm, and the size depended on the type of dopant. The determined energy band gap values of BiFeO₃, Bi_0.95Dy_0.05FeO₃, and Bi_0.95Zr_0.05FeO₃ thin films were 2.32 eV, 2.3 eV, and 2 eV, respectively. Doping of Dy and Zr at the Bi site led to reduced surface roughness. The prepared thin films exhibited enhanced ferromagnetic and ferroelectric properties. The remnant magnetization of Zr-doped BiFeO₃ was greater than that of the BiFeO₃ and Dy-doped BiFeO₃ thin films. From the obtained results, it was concluded that Zr-doped BiFeO₃ thin films are suitable for solar cell fabrication.     

A Comparative Study of the Semiconductor Behavior of Organic Thin Films: TCNQ-Doped Cobalt Phthalocyanine and Cobalt Octaethylporphyrin

The structure formed by cobalt phthalocyanine (CoPc) and cobalt octaethylporphyrin (CoOEP) with electron-acceptor tetracyano-π-quinodimethane (TCNQ), was studied by Density Functional Theory (DFT) methods. According to theoretical calculations, both cobalt systems can establish dispersion forces related to TCNQ and also in both cases the link between them is built by means of hydrogen bonds. Based on the results of these DFT calculations, we developed experimental work: the organic semiconductors were doped, and the thermal evaporation technique was used to prepare semiconductor thin films of such compounds. The structure of the films was studied by FTIR and Raman spectroscopy. The optical properties of the CoPc-TCNQ and CoOEP-TCNQ films were investigated by means of UV-Vis measurements. The results obtained were used to estimate the type of transitions and the optical bandgap. The results were compared to the previously calculated theoretical bandgap. The CoOEP-TCNQ film presented the smallest theoretical and experimental bandgap. Finally, the electrical properties of the organic semiconductors were evaluated from a PET (polyethylene terephthalate)/indium tin oxide (ITO)/cobalt macrocycle-TCNQ/silver (Ag) device we prepared. The CoOEP-TCNQ-based device showed an ohmic behavior. The device manufactured from CoPc-TCNQ also showed an ohmic behavior at low voltages, but significantly changed to SCLC (space-charge limited conductivity) at high voltage values.     

低温熔盐中电沉积Sm-Co合金膜及其磁性能

在353 K的尿素-乙酰胺-NaBr-KBr熔体中, 用恒电位电解法在Cu基片上制备了Sm-Co合金膜. 利用循环伏安法研究了熔体的电化学行为. 电化学实验结果表明, 在Pt电极上, Co(II)+2e→Co(0)是一步完全的不可逆反应; 测得CoCl2-尿素-乙酰胺-NaBr-KBr熔体中, Co(II)在Pt电极上的传递系数α=0.31, 扩散系数D0=4.78×10^-5 cm2·s-1; Sm(III)难以单独沉积, 但能被Co(II)诱导共沉积, 在不同阴极电位下制备出不同Sm含量的非晶合金膜. 用等离子发射光谱仪(ICP)检测薄膜成分, 用SEM观察了薄膜的表面形貌结构, 用XRD和振动样品磁强计(VSM)分析样品退火前后的晶相和磁性能变化特征. 结果表明, 在923 K进行退火30 s后Sm-Co薄膜由非晶转变为多晶结构, 并以hcp晶相结构为主; 退火和Sm含量对Sm-Co合金膜的磁性能有重要的影响.     

Stress and Moisture-Sorption in Ozone-Annealed Films of Zirconium Oxide Obtained from Sol-Gel

The stress development in zirconium oxide films prepared by sol-gel and annealed under ozone-enriched oxygen has been investigated. The organic compounds are mostly oxidized at 200°C with ozone and the stress rises up to higher values than the stress in films annealed with pure oxygen between 200 to 400°C. During exposure to humid air of films annealed at 150°C under pure or ozone-enriched oxygen chemical transformations of organic compounds have been observed. The moisture-induced stress change during film exposure to the ambient air also has been investigated. The competition between hydration of ZrO₂, H-bound formation, surface ionization and capillary condensation mechanisms is discussed.     

硼酸盐晶体及其溶液结构研究现状

硼酸盐结构十分复杂,主要针对硼酸盐晶体结构和硼酸盐水溶液结构问题,总结了水合硼酸盐晶体结构及其结晶行为,归纳了硼酸盐水溶液中硼酸盐的主要存在形式及其结构研究,并侧重介绍和评价了电导/电势滴定、红外(IR)、拉曼光谱(Raman)、11B核磁共振等方法在硼酸盐溶液结构研究方面的进展,指出了未来的发展方向.     

ZnO自组装薄膜的可控生长及其光催化性能

通过改变工艺参数, 制得了粒径可控的ZnO自组装薄膜. 该薄膜在可见光区域出现了光子带隙. 以染料甲基橙的光催化降解为模型评价了ZnO自组装薄膜的光催化活性. 利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征了ZnO的晶体结构和微观形貌. 实验结果表明, ZnO自组装薄膜在太阳光照射下表现出良好的光催化性能, 其光催化活性随着ZnO颗粒粒径的减小而提高. ZnO自组装薄膜光催化降解甲基橙的反应符合一级反应动力学规律.     

二氧化钛薄膜的低温制备及其性能表征

通过水煮法在较低温度下制备了均匀、透明的TiO2-SiO2复合薄膜,利用XRD、AFM和UV-Vis光谱等手段对薄膜的物相、表面形态结构和透明性进行了表征,分析了SiO2的添加对薄膜性质的影响.并利用紫外光照降解罗丹明B溶液评价了薄膜的光催化活性及其影响因素.实验结果表明,通过水煮法在较低温度下制备的薄膜具有较高的光催化活性,适量SiO2的添加能够提高薄膜的光催化活性.     

Effect of Antioxidants on Stability of Aqueous Solutions of Selenurea and on Properties of Lead Selenide Films Obtained with These Antioxidants

Spectrophotometric method was used to study the kinetics of the process in which aqueous solutions of selenurea of various compositions are oxidized. Significant differences between the stabilities of selenurea solutions were revealed in relation to the selenurea concentration and also to the acidity, or alkalinity of a medium. It was shown that the stability of selenurea solutions is affected by additives of various antioxidants: sodium sulfite Na₂SO₃, ascorbic acid C₆H₈O₆, hydroxylamine chloride NH₂OH·HCl, hydrazine hydrate N₂H₄·H₂O, and tin chloride SnCl₂·2H₂O. It was found that using a 1 : 1 mixture of antioxidants Na₂SO₃ and C₆H₈O₆ substantially raises their antioxidant activity and stabilizes the aqueous solutions of selenurea during up to five days. A hydro-chemical precipitation in the acetate—ethylenediamine reaction system in the presence of the antioxidants under study was used to obtain lead selenide films of stoichiometric composition with thicknesses of 230?670 nm. With the Na₂SO₃ + C₆H₈O₆, Na₂SO₃, C₆H₈O₆, and SnCl₂ antioxidants used to stabilize selenurea solutions, a tendency is observed toward a decrease in the lattice constants of PbSe films from 6.1531 ± 0.0003 to 6.1367 ± 0.0002 Å, an increase in the share of nanosize particles, and rise in the PbSe energy gap width from 0.78 to 1.0 e V.

     

Organosilicon Amidophosphates and Their Eu and Er Complexes in Solutions and Films: Spectral and Luminescence Properties

Fluorescence and fluorescence excitation spectra of phosphorus-containing organosilicon ligands O = PX₂NHR (X = NMe₂, OPh; R = CH₂CH₂CH₂Si(Oet)₃ and their Eu(III) complexes in acetonitrile solutions and in films are studied. In UV region (285–420 nm), bis(dimethylamido)triethoxysilylpropylamidophosphate (X = NMe₂) and diphenyltriethoxysilylpropylamidophosphate (X = OPh) exhibit two emission bands, whose position and intensity depend on the nature of substituents at the phosphorus atom. The Eu complexes show the ligand and the cation luminescence. The emission bands of coordinated ligands are shifted to long-wave region. The cation luminescence appears as three or four bands due to f-f transitions from the excited ⁵ D ₀ level to the lower ⁷ F _1–4 levels. The most intense transition is ⁵ D ₀ → ⁷ F ₂. The emission band in a region of 420 nm appears in solutions and films prepared from both pure ligands and their Eu(III) complexes. This band is due to luminescence of spatially crosslinked nanoparticles of sesquioxane structure. The intensity ratio of the Eu³⁺ emission bands changes when going from solutions to films, the emission intensity increases in a range of 420 nm. Films containing incorporated Er complexes with amidophosphates show intense luminescence of a matrix at 430 nm and a series of weak narrow bands due to the Er³⁺ cation at 550–700 nm.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 7, 2005, pp. 550–558.Original Russian Text Copyright © 2005 by Semenov, Cherepennikova, Klapshina, B. Bushuk, S. Bushuk, Douglas.     

Synthesis of Carboxylated Monodisperse Latexes and Their Self-Organization in Thin Films

The capability of carboxylated latexes of poly(methyl methacrylate) and copolymers of styrene with glycidyl methacrylate or methacrylic acid for self-organization in thin films was studied in relation to the compositions of the dispersion medium and polymer and to the latex particle size.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 161–167.Original Russian Text Copyright © 2005 by Men’shikova, Shabsel’s, Evseeva, Shevchenko, Bilibin.     

酸解淀粉物理化学性质的研究

玉米淀粉和马铃薯淀粉分别在35C条件下用浓度为2．4mol／L的HCI处理不同时间,采用X射线衍射分析、差热分析和扫描电镜等测试方法对酸解后的淀粉颗粒进行结构和性能分析。结果表明,淀粉的酸解过程可分为两个阶段：首先淀粉无定形区进行水解,颗粒结晶度、结晶热稳定性和酶解速率增加;随着酸解时间的延长,结晶结构受到破坏,热稳定性降低,达到酶解平衡的时间减少。酸解4d时,玉米淀粉和马铃薯淀粉颗粒的结晶均最完整,结晶转变温度最高,分别为87．0C和93．5C。     

新型锍鎓盐类光生酸剂的合成及产酸性能研究

成功合成了两种新型锍鎓盐类光生酸剂,其结构经¹1HNMR和MS分析确认,并对其基本物性及在405、365nm光下乙腈溶液中的分解及产酸性能进行了研究,通过计算得出了分解及产酸量子产率.结果表明,两种化合物有较高的热分解温度和在常用有机溶剂中有较好的溶解性;在405nm光源下,4-(9′-苯基蒽基)苯基三氟甲磺酸锍鎓盐(PAGS1)和4-(4′-N,N-二乙基-1′-苯乙烯基)苯基三氟甲磺酸锍鎓盐(PAGS2)的分解量子产率分别为10%和15%,产酸量子产率为8.1%和13%;但在365nm光源下,分解及产酸量子产率均很低,说明两种光生酸剂对于405nm波长的光较敏感,适宜作为405nm光源下的光生酸剂.     

聚合物熔体膜在基体表面的润湿和铺展行为

聚合物熔体膜在基体表面上的润湿和铺展行为受铺展系数和Hamaker常数影响。对于不能在基体表面上铺展的聚合物膜,当处于其玻璃化温度以上时,聚合物熔体膜将破裂,出现非连续区域。随着体系处于聚合物玻璃化温度以上时间的延长,非连续部分尺寸不断增长,增长速率与表面张力、聚合物粘度、聚合物液滴在基体表面的平衡接触角等因素有关,平衡后聚合物以液滴的形式在基体表面稳定存在。将带功能端基聚合物加入不能在基体表面上铺展的聚合物中,通过修饰聚合物与基体界面或改变聚合物熔体膜的表面张力,可以使原来不能在基体表面铺展的聚合物保持稳定。本文综述了聚合物熔体膜的铺展和润湿动力学研究进展,并归纳了使聚合物熔体膜稳定的方法。     

A Study of the Authophobic Dewetting in Thin Polymer Films

We have investigated the dewetting behaviour of a thin polystyrene film on top of cross-linked network of the same polymer. By changing the cross-linking density, the dynamic of the dewetting is modified. The behaviour of the contact angle and dewetting velocity can be related to the interfacial width between the polymers. We observe moreover that while the lost of entropy of the network connected to the penetration of the free chains will favour the dewetting; the possible presence of “connectors” between the layers will tend to stabilize the wetting. By modifying the entropy of the mesh by swelling the cross-linked system with a reservoir of the same polymer, the mesh is saturated and a stable interface without interdiffusion between the layers is obtained: in this case a constant contact angle and slippage length are obtained. Networks with higher cross-linking density are more difficult in general to swell – the mesh size is smaller - and the complete saturation is not reached.     

溶胶-凝胶方法制备ZnO:Al薄膜及其制备工艺条件研究

采用Sol-Gel工艺在玻璃基片上制备出C轴择优取向性、高可见光透过率以及高电导率的Al³⁺离子掺杂的ZnO透明导电薄膜ZnO:Al(ZAO薄膜).并研究了退火温度、Al掺杂量等对其光电性能的影响.结果表明,溶胶-凝胶法制备ZAO薄膜的最佳工艺条件为:溶胶浓度0.75 mol/L、掺杂量1.5 atm%,镀膜层数10层(厚度约为136 nm)、退火温度600℃.     

Effect of Microwave Radiation on Physicochemical Processes in Solutions and Heterogeneous Systems: Applications in Analytical Chemistry

The hydrolysis of inorganic and organic compounds, the complexation of metal ions with organic reagents in solutions and adsorbent phases, and the oxidation of organic substances with acids were exemplified in the context of a proposed approach to studies of the effect of microwave radiation on chemical reactions. Microwave digestion was considered as a step that combines various physicochemical interactions.