1,721,171 research outputs found
CONDUCTING POLYMER BLEND THIN-FILMS FROM GRANULAR METAL POLYMER COMPOSITES
No full textAn original method of growing a new class of thin films of composite conducting materials is described. A technological approach which allows the deposition of a fluorinated polymer-polypyrrole alloy on a solid substrate is outlined. This procedure employs a cosputtered granular metal in which the metal grains are chlorinated to produce an oxidizing agent capable of promoting pyrrole polymerization. Morphological, optical and electrical characterization of the material are reported. The low-temperature behaviour of the resistance was investigated. The polymer blend seems to be less disordered than polypyrrole thin films grown on an oxidizing salt pattern from the vapour phase
Site-selective chemical-vapor-deposition of submicron-wide conducting polypyrrole films: Morphological investigations with the scanning electron and the atomic force microscope
No full textWe report morphological investigations of polypyrrole thin films deposited by means of a self-aligning vapor phase technique onto glass, silicon and silicon dioxide substrates, coated with an oxidizing precursor. The variation of the deposition parameters allows the control of the film microstructure which can be fibrillar and strongly anisotropic or globular and tendentially isotropic. Patterning of the precursor by electron-beam lithography allows the production of submicron wide lines as shown by both the scanning electron microscope and the atomic force microscope. (C) 1996 American Institute of Physics
Molecules on Gold surfaces: what they do and how they go around to do it
No full textA review of the computational models that describe the interactions of molecules on gold surface
SENSING PROPERTIES OF POLYPYRROLE POLYTETRAFLUOROETHYLENE COMPOSITE THIN-FILMS FROM GRANULAR METAL POLYMER PRECURSORS
No full textA new class of sensor-oriented composite conducting thin films was grown utilizing an original method. The technique is based on the chemical polymerization of pyrrole (PY) vapours onto an oxidizing salt pattern obtained via chlorination of a co-sputtered granular metal thin film. Time stability of the samples realized with this technological approach and their response to exposure to different atmospheres were studied; the behaviour of the material subjected to mechanical strain was also investigated
LOW-FREQUENCY RESISTANCE FLUCTUATION MEASUREMENTS ON CONDUCTING POLYMER THIN-FILM RESISTORS
No full textLow-frequency resistance fluctuations were measured on-polypyrrole thin-film resistors. The samples were obtained by chemical-vapor deposition onto copper chloride patterned precursors. The measurements were devoted to characterize the noise spectral density of constant-current-biased samples. The dependence of the noise magnitude on the applied de voltage was studied revealing that the noise cannot be ascribed only to equilibrium resistance fluctuations. Application of the Hooge formula provided an estimate of carrier density in the material
CONTROLLED PHASE SEPARATION IN CONJUGATED POLYMER BLENDS INDUCED BY THERMOLITHOGRAPHY
No full textThe big interest in conjugated polymers is due to their easy solution processability, which endows them with several prospects, from low-cost processing, to opportunity of creating materials with new properties by simple mixing solutions, so research has focused on to optimize the blends properties in order to enhance optoelectronic device performance. Possibility to rules a phase separation in conjugated polymer blends has wide range of applications in optoelectronics, because both charge transport and charge separation are influenced by presence of phase segregation. Here we present a new method of controlling phase segregation in conjugated polymer blends by using a scanning probe microscope
Thermal processes in metal-coated fiber probes for near-field experiments RID B-4222-2010
No full textWe have used a ray optics model to calculate the optical power absorbed in the metal coating of apertured probes for scanning near-field optical microscopy. We have then introduced the absorbed power profile into the heat balance equation to calculate the temperature of the probe as a function of the distance from the apex. By comparing our results with available experimental data, we demonstrate accurate prediction of both the temperature profile along the probe, and the temperature increase per mW of power launched into the fiber (60.7 versus 60 K/mW at 25 mu m from the apex). (c) 2005 American Institute of Physics
GAS AND VAPOR EFFECTS ON THE RESISTANCE FLUCTUATION SPECTRA OF CONDUCTING POLYMER THIN-FILM RESISTORS
No full textThe effects of various vapours on the power spectrum of the resistance fluctuation of polypyrrole thin-film resistors were studied. An ultra-low noise amplifier and current source were built in order to detect the very low signal and bias the resistors. The samples were obtained by means of chemical vapour deposition on to oxidizing precursors. The method was successfully extended to n-methylpyrrole and thiophene polymerization
Inverted organic photovoltaics with a solution-processed ZnO/MgO electron transport bilayer
Full text linkElectron transport layers (ETLs) have been instrumental in breaking the efficiency boundaries of solution-processed photovoltaics. In particular, bilayer ETLs with an MgO top component have afforded tremendous success in various solution-processed systems, such as perovskite photovoltaics, however, their application in the promising technology of organic photovoltaics is limited. In this work, we fabricate organic photovoltaic devices incorporating a “bilayer” ZnO/MgO ETL instead of a single ZnO ETL, so as to reduce the leakage current and boost the power conversion efficiency. The ZnO/MgO ETL is shown to have a more uniform top surface and a lower work function compared to the single ZnO ETL which is expected to be beneficial to electron extraction. Furthermore, we demonstrate that insertion of the thin (≲ 10 nm) MgO interlayer in devices leads to a reduced leakage current and an increase in the shunt resistance. Application of the MgO interlayer boosts the short circuit current density and fill factor, and enhances the power conversion efficiency by ∼10% (relative increase) thereby demonstrating a facile approach to push the efficiency of organic photovoltaics to higher levels
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