Heavy phosphate adsorption on amorphous ITO film electrodes: nano-barrier effect for highly selective exclusion of anionic species

We prepared an amorphous indium tin oxide (ITO) film and studied it with respect to its surface characterization and the effect of phosphate adsorption on its electrochemical properties. The film was deposited using RF sputtering under ambient low-oxygen conditions at room temperature. The XPS results revealed that the amount of phosphate adsorbed on the amorphous ITO film was more than 4.6 times greater than that adsorbed on commercially available polycrystalline ITO film in spite of the smaller microscopic surface area of the former. Electrochemical responses for anionic species such as L-ascorbic acid (AA) and 3,4-dihydroxyphenylacetic acid (DOPAC) on the phosphate-adsorbed ITO film electrodes were more effectively suppressed at the amorphous ITO film electrode than at the polycrystalline ITO film electrode when a phosphate-containing electrolyte was used. Such suppression could be attributed to the electrostatic repulsion between the anionic species and more heavily adsorbed phosphate on our amorphous ITO film electrode surface. This effect is made more pronounced by increasing the phosphate concentration to 1 mM. With 1 mM phosphate, the amorphous ITO film electrode showed the highest selectivity for dopamine (DA) against the anionic species, namely, 880 for DA/AA and 330 for DA/DOPAC, respectively. In contrast, the selectivity was 120 for DA/AA and 20 for DA/DOPAC with the polycrystalline ITO film electrode.     

Preparation of Amorphous Film on Ni-S Alloy by Electroplating Method

IntroductionRecently,amorphousalloyshaveattTactedconsiderableattentionasnewfunctionalmaterial.Theycanbeattainedbyelectroplating,suchasplatingNi-P,Ni-B,Fe-W,Ni-Mo,Fe-P,etc..ThestructureofcodepositednickelandsulfurwasfirststudiedbyBrilllwithXRD.He,however,didnotdiscussthemethodofcodepositingnickelandsulfur.Afterwards,thereweresomereportsonNi-Sdeposit.Ingeneral,aNi-SdepositcanbeobtainedbyelectroplatingfromaWattsbathcontainingsuchsulfursourcesasthiocyanateKCNS',thioureaNH,CSNH,',andso…     

X射线荧光光谱法快速测定FeSiB非晶合金薄带中硅、硼、铁

提出了以自制的标准样品,采用单点法绘制校准曲线,利用X射线荧光光谱仪测定FeSiB非晶薄带样品中硅、硼和铁的含量。对于4个FeSiB非晶合金薄带样品中硅、硼和铁进行了10次测定,其分析结果的相对标准偏差分别为0.4%~0.5%、1.3%~4.2%和0.2%~0.4%。方法的分析结果与火花源原子发射光谱法、化学重量法和电感耦合等离子体原子发射光谱(ICP-AES)法的测定值吻合较好。方法快速、简便,薄带样品无需制样,适用于FeSiB非晶合金薄带的快速成分分析。     

X射线荧光光谱法快速测定FeSiB非晶薄带中Si,B,Fe的含量合金薄带中硅硼铁

提出了以自制的标准样品,采用单点法绘制校准曲线,利用X射线荧光光谱仪测定FeSiB非晶薄带样品中硅、硼和铁的含量。对于4个FeSiB非晶合金薄带样品中硅、硼和铁进行了10次测定,其分析结果的相对标准偏差分别为0.4~0.5%,1.3~4.2%和0.2~0.4%。本方法的分析结果与火花源原子发射光谱法、化学重量法和ICP-AES的测定值吻合较好。本方法快速、简便,薄带样品无需制样,适用于FeSiB非晶合金薄带的快速成分分析。     

The photocatalytic properties of amorphous TiO2 composite films deposited by magnetron sputtering

The preparation of amorphous TiO₂ film coupled with various metal-oxide semiconductors and their photocatalytic activities evaluated by photo-degradation of methylene blue and rhodamine B aqueous solution are briefly reviewed. The proposed photoreaction mechanism of the amorphous composite semiconductor and the differences between amorphous TiO₂-based films and crystalline TiO₂ photocatalytic materials in terms of preparation and usage are addressed. The inactive intrinsic amorphous TiO₂ film coupled with various metal oxides were found to gain high photocatalytic activity. These dopants induce forming new energy levels in the band gap of TiO₂ to enhance the charge separation of the photoinduced electrons and holes and extend the light absorption of TiO₂-based photocatalytic films into the visible region. In addition, two different effects of coupling metal oxides have been proved: the introduction of oxides of W, Cr, V, Ag, and Mo can significantly increase the photo-reactivity of amorphous TiO₂ film, while the combination of oxides of Zr, Sn, Sb, Cu, Ta, Fe, and Ni cannot affect the inactivity of pure amorphous TiO₂ film.     

ρ-Si上电沉积制备镍-磷非晶薄膜催化剂

非品态合金作为一类新型催化材料，越来越引起人们的广泛关注．Ni－P非晶态合金催化剂的催化加氢性能研究尤为活跃［‘，’］，研究结果表明其活性明显高于Ni－P晶态合金和比表面积相当的Ni粉L＼从而具有实用价值．传统的非品态合金催化剂的制备方法，如真空蒸镀、真空溅射、液相急冷及离子注入等，存在设备复杂、耗能大，难以批量生产等缺点；化学法可制备粒度均匀的催化剂＊；但给提纯带来了一定困难，而电沉积制备非晶薄膜催化剂由于具有纯度高、能耗低、制作方便等优势而倍受青睐问利用半导体做载体沉积Ni－P非晶态合金，在光电催化…     

聚对苯二甲酸乙二酯非晶态膜片单轴热——拉伸中的结晶与松弛

用动态力学损耗温度谱作为测试手段,研究了非晶态PET膜片在78—112℃温度范围内的单轴拉伸。实验结果说明,在较低温度下所得结晶的拉伸试样,完全由于应变诱发结晶,发生在应力-应变曲线的屈服后应力开始上升的阶段。在较高温度下(90℃或更高)拉伸可得非晶态而且光学各向同性的试样,是由于分子链的小尺度取向在拉伸过程中已完全热松弛所致,而分子链的大尺度取向要通过高弹态流动而松弛,其速率较慢,用拉伸后试样两端固定时的应力松弛进行了观察。在较低温度下应力松弛后仍为非晶态,在较高温度下应力松弛到起始应力的1O％下才开始结晶。FTIR研究表明在这种状态下的结晶有一结晶诱导期,其时间尺度与应力松弛阶段相当。     

掺硼p型非晶硅薄膜的制备及光学性能的表征

以高氢稀释的硅烷(SiH₄ )为反应气体,硼烷(B₂H₆)为掺杂气体,利用RF-PECVD方法,在玻璃衬底上制备出掺硼的氢化非晶硅(a-Si:H)薄膜,研究了硼掺杂量对氢化非晶硅(a-Si:H)薄膜的光学性能的影响.利用NKD-7000 W光学薄膜分析系统测试薄膜的透射谱和反射谱,并利用该系统的软件拟合得出薄膜的折射率、消光系数、吸收系数等光学性能参数,利用Tauc法计算掺硼的非晶硅薄膜的光学带隙.实验结果表明,随着硼掺杂量的增加,掺杂非晶硅薄膜样品在同一波长处的折射率先增大后减小,而且每一样品均随着入射光波长的增加而减小,在波长500 nm处的折射率均达到4.3以上;薄膜的消光系数和吸收系数随着硼掺杂量的增大而增大,在500 nm处的吸收系数可高达1.5×10⁵cm^-1.在实验的硼掺杂范围内,光学带隙从1.81 eV变化到1.71 eV.     

The glass transition behaviors of low-density amorphous ice films with different thicknesses

The glass transition behaviors of amorphous ice with different thicknesses are studied by determining the heat capacity of low-density amorphous ice without crystallization using first principle molecular dynamics (FP-MD) and classical MD methods. The behaviors are also studied by analyzing hydrogen-bond network, the radial distribution functions, and relationship between hydrogen bond and electronic structures. It is found that the glass transition temperature (T(g)) in the range of 90 K < T < 100 K for 4 nm amorphous ice film by FP-MD method, and 120 K < T(g) < 130 K for 8 nm amorphous ice film by MD method. Meanwhile, T(g) decreases with the decreasing thickness of amorphous ice film, which is also validated by the theoretical model.     

Use of amorphous silicon films as sensors

Transport phenomena in an amorphous silicon film deposited by a glow discharge technique have been reviewed, and many interesting applications of this material in sensors are considered. A large Seebeck effect is observed in the highly-conductive amorphous silicon film and a thermopile power sensor has been developed using this film. The large elastoresistance effect observed in the film has been investigated for possible use in strain sensors, touch sensors and real-time correlators. The light-related phenomena and their sensor applications have also been briefly reviewed.     

Growth mechanism of amorphous carbon by liquid plasma electrolytic deposition

The growth mechanism of amorphous carbon film by the liquid deposition process is still unclear. In this study, the influence of applied voltages on the surface morphology and microstructure of amorphous carbon films was investigated as well as the bonding probability at the film/substrate interface, and a new mechanism of film growth was proposed from the electrochemistry and non‐equilibrium thermodynamics viewpoints. The results showed that growth of amorphous carbon film involved the island groove morphology; more graphitic carbons are present within the film as the applied voltage increased. A coupling model of the growth mechanism including the ionization–absorption–dehydrogenation process and the chemical volume polymerization is highlighted. Copyright © 2016 John Wiley & Sons, Ltd.     

Noncrystalline phases in poly(9,9-di-n-octyl-2,7-fluorene)

Selective formation of amorphous, nematic (N), and beta phases in poly(9,9-di-n-octyl-2,7-fluorene) (PFO) films was achieved via judicious choice of process parameters. Phase structure and film morphology were carefully examined by means of X-ray diffraction as well as electron microscopy. "Amorphous" thin films were obtained by quick evaporation of solvent. Slow solvent removal during film formation or extended treatment of the amorphous film with solvent vapor resulted in predominantly the beta phase, which corresponds to a frozen (due to decreased segmental mobility upon solvent removal) and intrinsically metastable state of transformation midway between a solvent-induced clathrate phase and the equilibrium crystalline order in the undiluted state. The frozen transformation process is reactivated upon an increase in temperature beyond 100 degrees C. Compared to the amorphous film, extended backbone conjugation in the beta phase is evidenced from the emergence of a characteristic absorption peak around 430 nm near the absorption edge. For films of frozen nematic order (obtained by quenching from the nematic state), the conjugation length is also greater than the amorphous films as revealed by an absorption shoulder around 420 nm. Well-behaved single-chromophore emission with single-mode phonon coupling was observed for the beta phase; in the case of nematic films, dual-mode phonon coupling must exist if single-chromophore emission is assumed. In comparison, the emission spectrum of the amorphous film of generally shorter conjugation lengths exhibited mixed characteristics of nematic and beta phases, implying the presence of minor populations of extended conjugation similar to those in nematic and beta phases, which are of biased weightings in the emission spectra. All these films consist of nanograins (ca. 10 nm in size) of collapsed chains; the films are therefore inherently inhomogeneous in this length scale. In combination with previous observations on the crystalline (alpha and alpha') forms, the phase behavior of PFO is then generally summarized in terms of relative thermodynamic stability.     

Photoluminescence spectral reliance on aggregation order of 1,1-Bis(2'-thienyl)-2,3,4,5-tetraphenylsilole

1,1-Bis(2'-thienyl)-2,3,4,5-tetraphenylsilole (1) was prepared and characterized crystallographically. Silole 1 exhibited aggregation-induced emission (AIE) behavior like other 2,3,4,5-tetraphenylsiloles. Unexpectedly, aggregates formed in water/acetone (6:4 by volume) mixture emitted a blue light that peaked at 474 nm, while aggregates formed in the mixtures with higher water fractions emitted green light that peaked at 500 nm. Transmission electron microscopy demonstrated that the aggregates formed in the mixture with water fraction of 60% were single crystals, while aggregates that formed in the mixture with water fraction of 90% were irregular and poorly ordered particles. The unusual PL spectral reliance on aggregation order was further confirmed by PL emissions of macroscopic crystal powders and amorphous powders of the silole in the dry state. PL spectral blue shifting was observed upon aging of the poorly ordered aggregates formed in mixtures with water fractions of 70-90%, and they finally exhibited the same blue emission as the crystalline aggregates. The as-deposited thin solid film was amorphous and it could be transformed to a transparent crystalline film upon treatment in the vapor of an ethanol/water (1:1 by volume) mixture, along with PL spectral blue shifting due to changing of aggregation order. It was also found that the crystalline film showed a blue-shifted absorption spectrum relative to the amorphous film and the shift of the absorption edge of the spectra could match that of corresponding PL spectra. The FT-IR spectrum of crystal powders of 1 displayed more vibration modes compared with that of amorphous powders, suggesting the existence of different pi-overlaps or different molecular conformations. The crystals of 1-methyl-1,2,3,4,5-pentaphenylsilole and hexaphenylsilole also showed blue-shifted PL emissions of their amorphous solids, with a comparable PL spectral shift of 1. Developing of a silole solution on a TLC plate readily brought about an amorphous thin layer. Our results suggest that crystalline films of AIE-active siloles are potential emissive layers for efficient blue OLEDs with stable color and long lifetime.     

Formation of Dissipative Structures in an Amorphous Film

The formation of nanothin spatial dissipative structures (SDSs) of hexagonal selenium with elastic rotational curvature of the lattice about [001] in an amorphous film was considered. It was established that nanothin SDSs form in thermal gradient treatment of an amorphous film by one-side heating of its lower surface at T = 453 K. The state of pseudo-single crystal, which precedes the formation of a nanothin SDS in an amorphous film, is a state with a high concentration of vacancies. Under the action of the temperature difference ΔT, vacancies and selenium atoms undergo thermal diffusion in the direction perpendicular to the surface of the pseudo-single crystal. It was shown that, when ΔT reaches critical values, there is a transition from the structure of a pseudo-single crystal to the structure of a rhombic nanothin SDS of hexagonal selenium. The heat flux through the nanothin SDS in the direction perpendicular to its surface ensures the entropy export to the environment. After the thermal gradient treatment of the amorphous film, the nanothin SDS is quenched by cooling it in air; in this process, there is quenching of nonequilibrium structural defects—atoms and vacancies displaced from equilibrium positions. The quenching makes the nanothin SDS stable. The formation of nanothin SDSs of hexagonal selenium with elastic rotational curvature of the lattice about [001] in an amorphous film occurs under conditions satisfying the theory of the formation of dissipative structures.     

Difference in Glass Transition Behavior Between Semi Crystalline and Amorphous poly(lactic acid) Thin Films

Summary: Semi crystalline and amorphous poly(lactic acid) (PLA) thin films exhibit different glass transition temperature and behaviour, as revealed by ellipsometry. For semi-crystalline poly(L-lactic acid) (PLLA) thin film (with crystalline content between 40 and 60%), the glass transition temperature (T_g) is found to decrease below a film thickness of 50 nm. This depression was interpreted in term of disentenglement effect which is likely to occur upon confining the amorphous PLA phase near a non interacting surface. New results performed on non completed films, i.e. isolated objects, also reveal the lower transition temperature, thus underlying the importance of the entanglement state of the polymer chains on their mobility. For amorphous PLA thin film, obtained from the L and D copolymer, two distinct glass transitions were observed, with the highest Tg attributed to the presence of some nano-phase domains, formed by a possible cooperation of the D and L blocks to form stereocomplexes sequences, within the film. Furthermore, if these T_g remained constant as film thicknesses decrease down to 50 nm, they were also found to slightly decrease for isolated objects, thus supporting the importance of the entanglement hypothesis on the glass transition.     

Transmission electron microscopy observations of composite polymer colloid nucleated by functionalized silica

In this work, functionalized nanometric silica particles were engaged in emulsion polymerization of ethyl acrylate. The morphological characterization of this composite material was performed by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). We were particularly interested in the state of encapsulation of the silica particles and their distribution in the latex film. Initialy, we successively studied both components of the composite: polymer beads and silica particles differ by their size and also by their contrast. In addition, it was possible to perfrom dark field TEM to study this system of two amorphous phases because their respective amorphous halos are not too close. Hence, we investigated the colloid material in aqueous media and after film formation. Although no ideal encapsulation is observed in the colloid in aqueous media, the distribution of silica in the latex film is good. SAXS results are in good agreement with TEM observations.     

Phase ordering in blend films of semi‐crystalline and amorphous polymers

A combination of optical and atomic force microscopy (AFM) is used for probing changes in the morphology of polymer blend films that accompany phase ordering processes (phase separation and crystallization). The phase separation morphology of a “model” semi‐crystalline (polyethyleneoxide or PEO) and amorphous (polymethylmethacrylate or PMMA) polymer blend film is compared to previous observations on binary amorphous polymer blend films of polystyrene (PS) and polyvinylmethylether (PVME). The phase separation patterns are found to be similar except that crystallization of the film at high PEO concentrations obscures the observation of phase separation. The influence of film defects (e.g., scratches) and clay filler particles on the structure of the semi‐crystalline and amorphous polymer films is also investigated.     

Modelling the dielectric function of thin films measured by spectroscopic ellipsometry: determination of microstructure and density

The dielectric function of thin-film amorphous hydrogenated silicon (a-Si:H) deposited by the glow discharge and hot wire technique has been investigated by spectroscopic ellipsometry. An improved interpretation of the ellipsometric data taking into account the influence of hydrogen incorporation into the amorphous network enables to determine the film density and the void volume fraction of the material. Thus ellipsometry provides a convenient and contactless means of characterizing the structural properties of thin films. The film density varies considerably with substrate temperature and hydrogen content depending on the individual deposition technique. A reduction of film density is mainly caused by the formation of voids in the amorphous network. The influence of the substrate temperature on the growth of dense a-Si: H films is pointed out.     

Spontaneous alloying of gold clusters into nanometer-sized antimony clusters

Alloying behavior of gold into nm-sized amorphous antimony (a-Sb) clusters has been studied by transmission electron microscopy (TEM), employing gold clusters in contact with a-Sb clusters. In order to produce gold clusters on individual a-Sb clusters, a-Sb clusters on an amorphous carbon film were cooled down to 96 K, and gold was then condenced on the film. When gold clusters in contact with a-Sb clusters are gradually heated from 96 to 290 K, dissolution of gold into a-Sb clusters sets in around 200K and clusters of a-(Sb-Au) alloys are produced. With increasing annealing temperture, more gold is absorbed into individual a-Sb clusters, and when the gold concentration in a-(Sb-Au) clusters reaches to the stoichiometric composition of AuSb₂, these amorphous clusters crystallize into AuSb2 clusters. The crystallization temperature decreases with decreasing size of initial a-Sb clusters.     

Nanocomposite ta-C films prepared by the filtered vacuum arc process using nanosized Ni dots on a Si substrate

Recently, structural manipulation of tetrahedral amorphous carbon (ta-C) film at the nanometer scale has attracted much attention. We demonstrate a novel method to obtain a nanocomposite film where nanoscale columns of graphitic phase are embedded in a tetrahedral amorphous carbon matrix. When using a Si substrate with nanosized Ni dots on the surface, graphitic columns grew selectively on the Ni dots, while a dense ta-C film was deposited on the bare Si surface. The growth of the graphitic columns is closely related to the nanosized Ni dots that catalyze the graphitic-carbon formation in a filtered vacuum arc deposition condition.