新型高阻隔有机氧化硅薄膜制备

采用等离子体化学聚合,在氧化硅层表面聚合单层甲基丙烯酸缩水甘油酯(GMA)改善其脆性,提高氧化硅薄膜阻隔性能和柔韧性能的研究.通过无机氧化硅层和有机GMA层交叠沉积来研究不同沉积参数对薄膜的阻隔性能影响.红外光谱(FTIR)分析在1030 cm-1和1730 cm-1处出现硅氧和羰基特征峰表明沉积薄膜为氧化硅和GMA.通过透氧性能测试(OTR)表明,沉积薄膜叠合顺序为氧化硅/GMA/氧化硅并且叠合六层时阻氧性最好,OTR为0.125(ml/m2·24 h)(原膜为130(mL/m2·24 h)).表面形貌分析表明薄膜由表面粗糙度较高的氧化硅层和粗糙度较低的有机GMA混合叠加在一起,并进一步从表面形貌角度说明三层叠合时,薄膜OTR较好的原因.按照GB/T 10004-1998标准,采用CPP为内封层,湿式复合工艺实验表明,复合薄膜的热封层良好、机械性能好.     

Nanocomposite organic films on silicon

Metal-insulator-semiconductor structures were fabricated using 40-layers-thick Langmuir-Blodgett (LB) films of stearic acid (SA) on hydrophobic n-type silicon (n-Si) substrates. Cadmium sulphide (CdS) nanoparticles were introduced by exposure to H/sub 2/S gas for a period of 12 h. Samples containing CdS nanoparticles exhibit lower dc leakage current but higher effective dielectric constant. The effective dielectric constant of the CdS embedded SA matrix is found to be 5.1. The Poole-Frenkel effect is prevalent for charge transport in the LB films containing CdS nanoparticles at the field higher than 10/sup 7//spl middot/ Vm/sup -1/. The effect becomes saturated at higher fields.     

Thermal imaging using organic films

Advances in the synthesis of non-centrosymmetric molecules coupled with the recently acquired ability to incorporate them into stable three-dimensional arrays with a high degree of order, hold out exciting possibilities for the development of high quality, low cost organic materials for a variety of applications.

In this paper we review the efforts that have been made in engineering molecules so as to optimize their pyroelectric properties. Results are presented for three classes of organic material: (i) spin cast films of vinylidene fluoride- trifluoroethylene copolymer, (ii) ferroelectric liquid crystal polymers encapsulated in thin cells and (iii) organic superlattices assembled using the Langmuir-Blodgett (LB) technique.

When consideration is given to a figure of merit for a commercial device such as a thermal imager rather than to a single physical material parameter, LB films are shown to be the most attractive of the three options. In this paper we list their several advantages including reasonable pyroelectric coefficients, low dielectric loss, low piezoelectric activity and the ability to fabricate films of the required optimum thickness.     

Switching in organic polymer films

In this paper we discuss threshold switching effects in thin films of polymethylmethacrylate on molybdenum, silver, copper, graphite, Nesa and Nesatron substrates, using counterelectrodes of pyrolytic graphite. The similarities to corresponding phenomena in multicomponent chalcogenide alloys point to inherently common mechanisms. Lateral variations in switching characteristics are discussed in terms of trap distribution statistics.     

Electroactive soft materials with high stretchability and transparency

正Nowadays,with the rapid development of wearable devices,more and more electroactive soft materials have approached to the scene view of human and flexible polymer materials are the most widely studied in this field[1-5]. These materials can be applied in soft robotics,sensors,batteries and so on[6-8]. However,flexible     

Cesium-incorporated indium-tin-oxide films for use as a cathode with low work function for a transparent organic light-emitting device

Transparent organic light-emitting devices (TOLEDs) were successfully fabricated utilizing a novel transparent conducting cathode with low work function. Cesium-incorporated indium-tin-oxide film was deposited on the organic layers with negligible damage by simultaneous operation of RF magnetron sputtering using an ITO target and vacuum evaporation of metallic cesium. Incorporation of cesium in the ITO film was confirmed by XPS analysis. The work function (4.3 eV) determined by photoelectron spectroscopy in air (PESA) was lower than that of 0.3-0.4-eV without cesium-incorporation and stable under the atmospheric environment. The electron injection efficiency of cesium-incorporated ITO cathode in the present transparent OLED fabricated was comparable to that of the previous double-layered structure comprising of ITO cathode and an organic buffer layer (BCP) doped by evaporation of cesium [T. Uchida, S. Kaneta, M. Ichihara, M. Ohtsuka, T. Otomo, D.R. Marx, Jpn. J. Appl. Phys., 44, No. 9 (2005) L282].     

Ethanol-mediated metal transfer printing on organic films

Ethanol-mediated metal transfer printing (mTP) is a soft method, which allows to efficiently deposit metals onto various organic surfaces for applications in organic electronics. This simple approach in based on the stronger adhesion of the metals to the organic materials in the presence of thin ethanol layer between the metallized PDMS and the substrate due to the capillary action. Patterns with a resolution of at least 20 μm have been obtained on organic polymeric materials and photoresists without heating or applied pressure. Compared to other methods ethanol mediated mTP is considerably faster and has smaller limitations on the stamp depth. Residual silicone layer detected on the metal surface after the transfer by XPS studies has been mostly removed by UV/ozone treatment. Organic field-effect transistors (OTFTs) based on the metal electrodes deposited by mTP have been successfully fabricated and tested.     

Lasing action in organic semiconductor thin films

Lasing action in optically pumped thin films of organic semiconductors has recently been demonstrated in a variety of materials employing a variety of cavity configurations. The excitation intensities required for lasing in optically pumped films are comparable to the electrical current densities achievable in light emitting devices based on these materials, opening the door to the possible realization of organic diode lasers. However, the design of diode laser structures is complicated by the relatively low charge carrier mobilities of organics. It has also been shown that the optical properties of organic films under electrical excitation are affected by the formation of polarons, imposing yet another obstacle for realization of these devices. The continuing research on organic diode lasers is motivated by the unique properties of these devices, such as narrow spectral emission linewidth and the temperature independence of laser output power and emission wavelength, which may be advantageous in a number of applications.     

Thin organic films by atmospheric-pressure ion deposition

Interest in thin films of functional organic materials has increased enormously in recent years because of the wide range of possible applications. Here we report an experimental setup for processing various organic materials into thin structured films under atmospheric pressure. The technique is based on an electrospray process. Microdroplets are initially formed and dried, generating ions that are extracted by electrostatic lenses. Thin structured films are then produced by the deposition of the resulting ion beam onto a moveable target. The technique offers several interesting features, including precise control of film thicknesses. We have also made experiments to investigate structured deposition, this being the first step towards the production of thin films where in all three dimensions the chemical composition can be chosen at will. This might provide a simple approach towards creating thin structured films and composites that are currently unattainable.     

Enhanced backscattering from organic laser gain media bounded with rough gold films

The enhanced backscattering from organic laser gain media that are bounded with one-dimensional (1-D) and two-dimensional (2-D) rough metal films was investigated. We prepared several organic optical gain materials by doping laser-active dyes in matrices of acrylic polymers. These materials produced efficient and broadband fluorescence emission in the visible wavelengths during the pumping of a pulsed YAG or cw argon laser. These gain materials were sliced and coupled with 1-D or 2-D randomly rough gold films with large slopes. An experimental investigation was carried out with a He-Ne laser as the scattering source and the optical gain provided by a cw argon laser. The enhanced backscattering and the satellite peaks located about the enhanced-backscattering peak were obviously amplified, with their widths narrowed. These experimental results agree well with previous theoretical predictions.     

Electroactive Ionic Soft Actuators with Monolithically Integrated Gold Nanocomposite Electrodes

Electroactive ionic gel/metal nanocomposites are produced by implanting supersonically accelerated neutral gold nanoparticles into a novel chemically crosslinked ion conductive soft polymer. The ionic gel consists of chemically crosslinked poly(acrylic acid) and polyacrylonitrile networks, blended with halloysite nanoclays and imidazolium‐based ionic liquid. The material exhibits mechanical properties similar to that of elastomers (Young's modulus ≈ 0.35 MPa) together with high ionic conductivity. The fabrication of thin (≈100 nm thick) nanostructured compliant electrodes by means of supersonic cluster beam implantation (SCBI) does not significantly alter the mechanical properties of the soft polymer and provides controlled electrical properties and large surface area for ions storage. SCBI is cost effective and suitable for the scaleup manufacturing of electroactive soft actuators. This study reports the high‐strain electromechanical actuation performance of the novel ionic gel/metal nanocomposites in a low‐voltage regime (from 0.1 to 5 V), with long‐term stability up to 76 000 cycles with no electrode delamination or deterioration. The observed behavior is due to both the intrinsic features of the ionic gel (elasticity and ionic transport capability) and the electrical and morphological features of the electrodes, providing low specific resistance (<100 Ω cm^?2), high electrochemical capacitance (≈mF g^?1), and minimal mechanical stress at the polymer/metal composite interface upon deformation.     

Electron energy loss spectra of NTCDA organic films

The electron energy loss (EEL) spectra of thin NTCDA films on the ZnO(0001) surface were measured. In the low-energy range (<60 eV), the EEL spectra (displaying the characteristic loss peaks at E _loss=4.0, 5.6, 12.5, and 14.5 eV) reflect the structure of transitions between the valence and conduction bands. As the primary electron energy increases, the dominating energy losses are due to the excitation of plasma oscillations at ?ω₁=6.5 eV (π plasmon) and ?ω₂=25 eV (π?σ plasmon).     

Photoelectron processes in heterojunctions based on organic films

The photoconductivity and photo emf have been studied in a heterostructure based on thin films of electron donor and acceptor organic compounds. It is established that the main process responsible for the photogeneration and separation of charge carriers is the decay of photoexcited molecular states at the interface between the donor and acceptor materials. The determining influence on the photoelectron processes in the organic heterostructure is produced by the energy structure of electron states at the interface. The role of the photoinduced intermolecular charge transfer in the development of photoconductivity in the given heterostructure is considered.     

Bipolar injection as a cause of electrical switching phenomena in thin organic films

An investigation of electrical conductance switching phenomena in thin organic films has been carried out. For thin films of p-quaterphenyl and tetracene grown in high vacuum the electrical conductance, dynamic capacitance and temperature patterns corresponding to the distribution of electrical current density have been measured. The measurements were carried out in vacuum as well as in humid air. It is suggested that previously reported switching phenomena are caused by field-induced bipolar injection of charge carriers.     

Fabrication of thin crystal films of organic compounds

A technique for thin film preparation from non-polar organic molecules based on the Langmuir technique is suggested. By removing the organic crystallites of organic molecules from the water surface to the substrate, high-quality textures were obtained with a simultaneous check of their thicknesses. The films produced were analysed by the transmission high-energy electron diffraction technique.