Silver Anode Research Articles

Ultrasmooth Silver Thin Film Electrodes with High Polar Liquid Wettability for OLED Microcavity Application

For a lab-on-chip application, we fabricate a blue bottom emitting strong microcavity organic light emitting diode (OLED), using very smooth and optically thin (25 nm) silver film as anode on a glass substrate. To improve the hole injection in the OLED device, PEDOT-PSS (poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid)) has been used, so the silver anode must present not only a very smooth surface but also a strong adherence on the glass and a high wettability to allow a good PEDOT-PSS spin coating deposition. To obtain these physical properties, different 5 nm thick nucleation layers (germanium, chromium, and hydrogenated amorphous carbon) have been used to grow the silver thin films by e-beam deposition. The Ge/Ag bilayer presents all the desired properties: this bilayer, investigated by ellipsometry, optical profilometry, contact angle measurements, and XPS analysis, highlights an ultrasmooth surface correlated with the film growth mode and a high wettability related to its surface chemical composition.

Experimental Fabrication of Small Flat-Panel Field Emission Lamp with Printed Carbon Nanotubes as Field Emitters

With effective screen-printing technique, the flat-panel field emission lamp (FPFEL) based on carbon nanotube as cold cathode material was fabricated. The prepared CNT paste was printed on the cathode glass plate to form the field emitter and sealed into the device vacuum room of FPFEL. For improving the display image uniformity, the discrete anode indium tin oxide (ITO) zones method was adopted, and the anode voltage could be applied through the silver anode connecting line for the different anode ITO zones. The anode insulation wall was fabricated to support the anode glass plate, which the deforming of anode glass plate would be avoided. The emission image for the small vacuum-sealed FPFEL with printed carbon nanotube as field emitters was presented. The fully-sealed FPFEL possessed high luminance brightness and better field emission uniformity.

Modification of silver anode and cathode for a top-illuminated organic photovoltaic device

We have demonstrated a top-illuminated organic photovoltaic device with a thick Ag anode and a thin Ag cathode capped with an α-naphthylphenylbiphenyl diamine (NPB) thin film. The surface of the Ag anode was oxidized by UV–ozone which improved the carrier collection and reduced the exciton quenching. Compared with the control device with an indium tin oxide anode, a 15.59 times reduction in the serial resistance and a 1.72 times increase in the shunt resistance were observed with a fill factor of 0.61 in such a device. The NPB capping layer not only improved the light transmission from the semitransparent cathode, but also hindered the formation of Ag island growth and thereby improved the device stability.

Hole Injection Layer of Thermally Evaporated Copper Oxide for Top Emitting Organic Light Emitting Diodes

We report the enhancement of the electroluminescent property of top emitting organic light emitting diodes (TEOLEDs) using thermally evaporated copper oxide as a hole injection layer (HIL) between UV ozone-treated silver (Ag) anodes and -bis[-(1-naphthyl)--phenylamino]biphenyl . The operation voltage of TEOLEDs at decreased from 6.2 to 5.0 V as a 2 nm thick layer was used as the HIL. layers were separately in situ deposited on both Ag and thermally evaporated -coated Ag and their interface dipole energies were quantitatively determined using synchrotron radiation photoemission spectroscopy. Secondary electron emission spectra revealed that the work function of is higher by 0.53 eV than that of Ag. The corresponding interface dipole energies were for Ag and for . As a result, plays a role in reducing the hole injection barrier from 1.63 to 0.96 eV, resulting in a decrease in the turn-on voltage of TEOLEDs.

E-beam deposited ultra-smooth silver thin film on glass with different nucleation layers: An optimization study for OLED micro-cavity application

A study on the optimization of a thin (25 nm) silver film deposited by e-beam on glass substrate has been performed in order to achieve a smooth, spike-free, mechanical resistant and semi-transparent electrical conducting layer to be used as anode of a blue bottom emitting organic light-emitting diode (OLED) micro-cavity. To improve the flattening of asperities, rough grains and spikes, that can induce short circuit in the OLEDs, as well as the mechanical adherence of the thin silver film on a cleaned borosilicate glass, different thin nucleation layers (such as Cr, Ge and a-C:H) have been built and tested. Both the nucleation layers as well as the silver films have been grown at different deposition rates. A thin (40 nm) poly(3,4-ethyl-enedioxythiophene)/polystyrene-sulphonate (PEDOT-PSS) layer has been deposited by spin-coating on the different bi-layer anodes to improve the hole injection into the OLED hole transport layer. The surface morphology of the silver thin films with and without PEDOT-PSS layer has been studied using a field emission gun scanning electron microscope (FEG-SEM) and a high resolution optical profiler. The optimized silver anode obtained using a 5 nm Ge nucleation layer and a high silver deposition rate (1.1 nm/s) has been successfully used to obtain a long lifetime, large area and short circuit free bottom micro-cavity OLED.

Printed organic diode backplane for matrix addressing an electrophoretic display

An organic matrix diode backplane for driving an electrophoretic display with an unpatterned front plane electrode is reported. Using thin film diodes instead of transistors as the active components in the pixels enable the backplane to be manufactured using roll-to-roll compatible printing processes. The backplane functionality is demonstrated in an electrophoretic display using 16 copper pixel electrodes, each of which is connected to two printed organic diodes. The printed diodes have sputtered copper cathodes and printed silver anodes. The diodes and pixels are arranged in a lateral 4 by 4 matrix structure with a dielectric layer separating the row and column electrodes. The dielectric, semiconductor and silver layers are all printed using a laboratory-scale rotary gravure press. The display module is finalized by laminating the front plane material onto the backplane.

改善银阳极有机发光二极管空穴注入特性研究进展

改善银阳极有机发光二极管空穴注入特性研究进展

A Simulation Model of Resistive Switching in Electrochemical Metallization Memory Cells (ECM)

AbstractThe storage principal of the Electrochemical Metallization Memory Cell is based on change of cell resistance induced by electro-chemical driven growth and rupture of a cupric or silver filament in an insulating matrix. This kind of switching was found in several materials as AgGeSe, CuGeS, silicon oxide or tungsten oxide [1].During write operation copper or silver is oxidized at the corresponding electrode and copper or silver ions are driven out of the copper or silver anode into the insulating matrix due to the applied field, whereas the insulating matrix serves as solid electrolyte. The silver or copper ions migrate towards the cathode. At the cathode electrochemical reduction occurs, and deposition of metallic copper or silver takes place. Fast diffusion paths in the solid electrolyte matrix or preferred nucleation sites (seeds) at the boundary lead to filamentary growth. This growing cupric or silver dendrite finally reaches the anode and switches the device to a low resistance state.Based on this switching mechanism a FEM simulation model was set up. To simplify the model space charges due to silver or copper migration are neglected. It is further assumed, that the conductivity in the solid electrolyte is only ionic. Hence, it is sufficient to solve the well-known Laplace equation to address the electric properties as well as ion migration. A “Level Set” method is used to track the boundary of the growing filament. The velocity of this boundary is proportional to the ionic current density calculated by Laplace equation. Based on this model simulations are applied to cell structures with multiple fast diffusion paths and seeds. Simulation results show that just one filament reaches the anode.In a second step, Butler-Vollmer boundary conditions are introduced. This nonlinearity leads to an exponential dependence between switching time and switching voltage. As switching voltage increases, switching time decreases.A simulation model capable of simulating ECM memory cells is presented. The model enables to simulate the behaviour of different cell geometries or different materials as solid electrolyte. Furthermore it gives deeper insight into the switching mechanism.This work was supported by the European project EMMA “Emerging Materials for Mass storage Architectures” (FP6-033751).

Transparent and conductive electrodes based on unpatterned, thin metal films

Transparent electrodes composed of ultrathin, unpatterned metal films are investigated in planar heterojunction (PHJ) and bulk heterojunction organic photovoltaic (OPV) cells. Optimal electrode composition and thickness are deduced from electrical and optical models and experiments, enabling a PHJ-OPV cell to be realized using a silver anode, achieving power conversion efficiency parity with an analogous cell that uses an indium tin oxide anode. Beneficial aspects of smooth, unpatterned metal films as transparent electrodes in OPV cells are also discussed in the text.

The modification of silver anode by an organic solvent (tetrahydrofuran) for top-emissive polymer light-emitting diodes

An organic solvent, tetrahydrofuran (THF), was employed to modify the Ag anode of a top-emissive polymer light-emitting diode (T-PLED) for improving the hole injection capability and the performance of a T-PLED device. The X-ray photoelectron spectroscope analysis shows that the THF molecules were chemically adsorbed on the Ag surface, forming oxygen-rich species by substrate-catalyzed decomposition. The THF-modification were found to enhance the hole injection on the Ag anode, decrease the threshold voltage, and increase the light intensity and luminous efficiency of a T-PLED device, attributing mainly to the increase of work function of the Ag anode.

Efficient top-emitting organic light-emitting diodes with a V2O5 modified silver anode

We fabricated efficient top-emitting organic light-emitting diodes (OLEDs) with silver (Ag) as an anode and samarium (Sm) as a semi-transparent cathode. The hole-injection barrier at the Ag anode/hole transporter interface is reduced by inserting a buffer layer of vanadium oxide (V2O5) between them. The ultraviolet photoelectron spectroscopy analysis shows that the hole-injection barrier is reduced by 0.5 eV. Both the V2O5 thickness and the organic layer thickness are optimized. The optimized device achieves a maximum current efficiency of 5.46 cd A−1 and a power efficiency of 3.90 lm W−1, respectively.

Tuning hole injection and charge recombination with self-assembled monolayer on silver anode in top-emitting organic light-emitting diodes

A series of n-alkanethiol, cyano-terminated n-alkanethiol, and fluorine-substituted benzyl mercaptans were used to modify the silver anode in the fabrication of top-emitting electroluminescent devices. The efficiency of charge injection and device performance were investigated. The study shows that the size/direction of the dipole associated with the monolayer-forming molecule serves to modulate the metal work function and the charge injection barrier, whereas the alkyl chain length allows a fine tuning of charge balance in the recombination zone. A high current efficiency of ∼10.2cd∕A and a luminescence of ∼10800cd∕m2 at 200mA were achieved with the NC–C11–SH-modified devices.

Li batteries with porous sol–gel cathodes

The structure presented is a high-capacity micro battery, lithium based, consisting of porous cathode, solid electrolyte and silver anode. A spinel LiNi0.4La0.1Mn1.5O4 sol–gel layer was deposited on a porous ceramic substrate to give high specific surface to the chip-like microbatteries. The anode used was thermally evaporated Ag and the electrolyte a sol–gel hybrid Li4SiO4 layer.

Silver as anode in cryolite—alumina-based melts

AbstractThe anodic behaviour of silver was investigated in cryolite—alumina-based melt. Silver has a lower melting point (ca. 960°C) than the other metals considered as possible inert materials for aluminium electrolysis. The working temperature used in aluminium industry is approximately 960°C, depending on the melt composition. Therefore, the stability of silver during the anodic process was tested at 870°C in an acidic electrolyte consisting of 65.5 mass % Na3AlF6 + 22.9 mass % AlF3 + 5.7 mass % CaF2 + 3.9 mass % LiF + 2 mass % Al2O3 with the melting point ca. 850°C. The electrolyte without alumina was prepared as well, with the melting point ca. 860°C. The resulting cryolite ratio (CR = n(NaF)/n(AlF3)) for both electrolytes was equal to 1.6. The behaviour of the silver anode was studied by voltammetry measurements. The electrochemical study showed that an oxidation reaction occurred at a potential below the oxygen evolution potential. Silver was not found to be stable under oxygen evolution. The degradation of the silver anode was apparent after electrolysis.

非鉄金属製錬プロセスと操業 竹原製煉所における貴金属製錬

In the precious metals processing line, raw slimes including metals and silver are first decopperized and deselenized, and then converted to noble lead in the melting and settling furnace. Thereafter, it is turned into a crude silver anode by cupellation with the residual lead from the lead refining process. This crude silver is refined by electrolysis to produce electrolytic silver. Electrolytic gold is produced from the crude gold obtained from the sediments of silver electrolysis and part of it is used to produce high purity gold for electronic industry. Aside from these metals, selenium, tellurium, platinum and palladium are recovered.Recently, We have some improvement in these processes.

Elektrochemische Synthese von Ag5Pb2O6

AbstractElectrochemical Synthesis of Ag5Pb2O6Ag5Pb2O6 was prepared by anodic oxidation of silver in a PbO2 suspension in an aqueous KOH solution. Phase purity was checked by a Rietveld‐fit of the X‐ray powder pattern, thermal and chemical analysis. The compound exhibits ionic conductivity. It' anisotropy leads to an orientation of the crystallites on the silver anode.

Investigation of Ti mesh-supported anodes for direct borohydride fuel cells

The use of titanium mesh-supported gold and silver anodes in direct borohydride fuel cells (DBFCs) is reported. The anodes were prepared by either thermal decomposition or electrochemical deposition and were characterised by scanning electron microscopy and X-ray diffraction analyses. The performance of the mesh electrodes was compared with that for carbon-supported electrodes. The mesh anodes gave current densities, for borohydride oxidation, up to 50% greater and cell power densities up to 20% greater than those obtained with carbon-supported anodes. The effects of catalyst loading and fuel cell operating conditions are also reported. Electrode stability was examined over a prolonged period.

Elemental speciation of different stages of silver metal recovery process using PEDXRF

The silver ore, anode mud, chimney power, concentrator sample and waste damp samples obtained from the Gümüşköy Silver Plant have been analyzed for their elemental constituents. The prepared samples were analyzed using a polarized energy dispersive X-ray fluorescence (PEDXRF) spectrometer. The result of the analysis shows the presence of many elements including rare earth elements (from Na to Th). The accuracy and precision of the technique for chemical analysis is demonstrated by analyzing USGS standards, GEOL, SILVER, K07-CoO Cobalt oxide, GBW 7109 Ijolite Sy and GBW-7309 Sediment.

TH‐C‐224C‐01: Relative Biological Effectiveness(RBE) and Dosimetry of Low Energy Photons(8keV) Generated Using Miniature X‐Ray Tubes

Purpose: To study the Relative Biological Effectiveness(RBE) and dosimetric characteristics of an 8keV photon beam generated by an insertable miniature electronic brachytherapy device developed by Advanced X‐ray Technology, Inc.(AXT). Method and Materials: The AXT X‐ray needle consists of a primary conventional X‐ray tube with silver anode producing a 22 keV beam focused through a collimator into the applicator needle which has a secondary copper target generating an 8 keV fluorescent beam. The radio‐resistant human tumor cell lines HGL21(glioblastoma) and MCF7 (breast) were irradiated at 22°C using the AXT miniature needle and compared with a Co‐60 beam at dose rates of approximately 6cGy/min and 12cGy/min. An extrapolation chamber was used in gradient mode to determine the dose rate within the AXT beam after initially determining the effective area of the collecting electrode in a Co‐60 beam using the Bragg‐Gray relationship. Results: Cell surviving fraction (SF) was the primary end point in assessing the radiobiological effect. For the 8 keV beam, SF was found to be 0.056 for HGL21 and 0.018 for MCF7 for a dose of 2 Gy. This yields an RBE of 4.4 for HGL21 and 5.5 for MCF7 cells lines. The dose rate in the 8keV beam was found to vary linearly as a function of extrapolation chamber electrode spacing. This allows the use of the slope of the ionization gradient to determine the dose. The dose rate measured in free space at the location where the cells were irradiated was found to be 15.4 cGy/min.Conclusion: These high RBE values are not surprising given the stopping power of the very low energy recoil electrons produced in this beam, and support the premise that the AXT device will be an effective tool to treat tumor sites like brain, breast and prostate in which radio‐resistance might limit conventional radiotherapy.

Characterization of silver-saturated Ge–Te chalcogenide thin films for nonvolatile random access memory

Programmable metallization cell structure with a device diameter of 2μm composed of Ag–Ge–Te chalcogenide films was prepared by a cosputtering technique at room temperature. The device with a 150nm thick Ag30(Ge0.3Te0.7)70 electrolyte switches at 0.2V from an “off” state resistance Roff close to 106Ω to an “on” resistance state Ron more than four orders of magnitude lower for this programming current. The switching characteristics were closely related with a diffusion of silver anode into silver-saturated GeTe electrolyte films.