Cathode contact

It is preferable for the cathode interface to have a low WF contact for efficient electron extraction. Low WF metals, such as calcium (Ca), barium (Ba) or magnesium (Mg), are usually inserted into the interface between Al and organic active layer to improve the device performance. However, the low WF metal is vulnerable to oxidation under ambient conditions, and electrode degradation is a major concern for this type of device. Therefore, the development of new interfacial materials to use as a cathode interlayer is still required. 

With the denser P(VDF-TrFE) nanoislands obtained by this method, a larger electric field, around 20 3 V in PCDTBTrPCyjBM film, can be induced by the P(VDF-TrFE) NPs, which is 50-100% higher than the electric filed generated by the 1-2 monolayer LB P(VDF-TrFE). However, Asadi et al. argued that ferroelectric functionalized PSC, with a trul/ ferroelectric interlayer, will be subjected to ferroelectric depolarization. They demonstrated that inserting a layer of a ferroelectric polymer in the solar cell stack only leads to improved PCE for non-optimized solar cells with non-Ohmic contacts. In fact, in the best-case scenario, the performance of the ferroelectric-material functionalized solar cell approaches that of optimized cells with standard LiF/Al cathodes. 

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The cell for this process is unlike the cell for the electrolysis of aluminum which is made of carbon and also acts as the cathode. The cell for the fused-salt electrolysis is made of high temperature refractory oxide material because molten manganese readily dissolves carbon. The anode, like that for aluminum, is made of carbon. Cathode contact is made by water-cooled iron bars that are buried in the wall near the hearth of the refractory oxide cell. 

The cell consists of a commercially available four-necked, 500-mL, round-bottomed flask equipped with a 34/45 standard-taper joint electrode assembly (Note 1), a 24/40 standard-taper joint purge and vent assembly, a mercury pool cathode (Note 2), a cathode contact (Note 3), a magnetic stirring bar (Note 4), and thermometer (inserted in a 10/18 standard-taper joint neck). The two platinum anodes of the electrode assembly (Note 1) are positioned in a horizontal plane ca. 1 cm above (Note 4) the mercury (Cathode) surface. 

L=10 cm) having the same cross section. The counter current liquid (0.5M acetic acid + 0.05M nitric acid) streams from the cathode to the anode. The column (c) contains a zone of an ion of high mobility (e.g. K, Cs, Rb) to protect the components in (b) against cathode contact. In the column (a) the actinides as a group,... 

Alumina electrolysis cells consist of a rectangular steel shell lined with a 25-35 cm layer of baked and rammed dense carbon, which provides both chemical resistance and the cathode contact with the electrolyte via steel bus bars imbedded in the carbon. Normal lining life is 4—6 years, after which it is replaced as large preformed slabs. Once a reduction pot has been started the bulk of the cathode current to the carbon lining is via the pool of newly formed molten aluminum in the bottom of the cell (Fig. 12.2). 

In this paper, hydrogenated amorphous silicon thin film transistors (a-Si H TFTs) fabricated on a metal foil substrate is reported for active matrix OLEDs (AMOLEDs) displays. The electrical properties of a-Si H TFTs fabricated on a metal foil substrate are introduced. To increase the stability of a-Si H TFTs fabricated at low temperature on a metal foil substrate, negative bias applied to metal foil substrate can also recover the shifted threshold voltage during idle time. A new cathode-contact structure employing a normal top-emitting OLED, which is suited to n-type a-Si H TFT backplane is proposed. 

In this section, we propese a new cathode-contact structure employing the normal TOLED (CCTOLED) that has an anode at bottom and a cathode on top (Fig. 21 )). We also compare the electrical characteristics between the CCTOLED and ACTOLED pixel structure. 

Fig. 21. Structure and circuit implementation of normal top-emission AMOLED (TOLED) pixel (a) anode-contact with a-Si H TFT (ACTOLED) and (b) cathode-contact with a-Si H TFT (CCTOLED)...

Process flow to make cathode-contact pixel structure... 

Fig. 22. Fabrication process flow of a newly proposed normal top-emission OLED pixel employing cathode-contact structure (a) a-Si H TFT, (b) reflective anode, (c) step-covering layer and separator, (d) organic layer evaporation through the shadow mask on the anode, (e) cathode evaporation.

Fig. 23. SEM image of fabricated cathode-contact type OLED pixel...

In this paper, electrical performances and new approaches to increase the stability of a-Si H TFT fabricated on a metal foil substrate were reported. A new cathode-contact structure employing a normal top emitting OLED also was proposed and comjjared with an anode-contact structure by experimental data. 

Cathode-contact structure pixel structure employing normal TOLED was proposed for a-Si H TFT backplane. The new top-emission AMOLED pixel structure employing the TOLED as well as the cathode-drain contact structure was proposed and fabricated. The structure of TOLED had a cathode at bottom and an anode on top. The negative photo-resist separator wall successfully patterned the pixel cathode layers. As the electrical performances of CCTOLED and ACTOLED were compared, the CCTOLED was verified more suitable for better display performance having a high luminance and a high contrast ratio. 

Chemically, the effects in anodic and cathodic contact glow discharge electrolysis are similar [54]. The major difference is the reduced rate of the various reactions taking place. In particular, no H202 production is observed. Nevertheless, 02 and OH radicals can be produced by the bombardment of the electrolyte-gas film interface by the electron streams. 

Cathodes have an effective depositions surface area of 1.67 m and there are 33 cathodes in a cell. A knife switch type is used for the cathode contacts. This type allows the cathode header bar to come in contact with both the clip and the equipotential bar, resulting in a wide contact area. With a self-weight contact type, the contact resistance is increased because the weight of the cathode is light at the initial stage of electrolysis. To minimize this disadvantage, the knife switch type has been consistently in use to the present time. 

In Figure 17.14c, the contact situation on the cathode side between the interconnect channel and the cathode is highlighted. The contact layer applied by wet powder spraying covers all channel areas (bottom, top, and flanks) and on the top side it looks fairly homogeneous and flat, ensuring good cathodic contact (the gap is due to sample preparation). 

What is the cell potential of a concentration cell that contains two hydrogen electrodes if the cathode contacts a solution with pH = 7.8 and the anode contacts a solution with [H+] = 0.05 M ... 

Wet Powder Spraying Bilayer cathodes consisting of cathode and cathode current collector layer can be manufactured by wet powder spraying (WPS). The cathode contact layer is also applied on the metallic interconnects by spraying. Limitations of the technology are the overspray (the amount of suspension which is sprayed past the object to be coated) and the formation of a suspension mist which needs to be extracted by suction. The overspray can be recycled, though. 

There are three common lithium anode configurations Li(Si) alloy, LiAl alloy, and Li metal in metal matrix, Li(M), where the matrix is usually iron powder. With the difference that the alloy anodes remain solids and the lithium in the Li(Fe) mix is molten in an activated cell, all three anodes participate in the cell reaction similarly. All may be used with the same FeS2 cathode and the same electrolytes. These electrolytes may be the basic LiCl-KCl eutectic electrolyte, LiCl-LiBr-LiF electrolyte for best ionic conductivity, or a lower-melting-point electrolyte such as LiBr-KBr-LiF for extended activated life. Since the FeS2 is a good electronic conductor, the electrolyte layer is necessary in order to prevent direct anode-to-cathode contact and cell short-circuiting. When molten, the electrolyte between the anode and the cathode is held in place by capillary action through the use of a chemically compatible (inert) binder material. MgO is the preferred material for this application. °... 

A common form of closed contact is the reed relay, where the sealed capsule consists of two Ni-Fe blades, coated in the contact area with a precious metal and sealed into a glass envelope filled with, for example, a N2-H2 mixture. The capsule is positioned within, or close to, a coil which induces the blades to contact magnetically when energized. The blades are usually gold-plated using a continuous belt-feed system, the cathode contact area being limited by judicious control of electrolyte level. 

Individual mounting. This is necessary for large, single specialized workpieces, e.g. a one-off computer frame which may need multiple cathode contacts and auxiliary anodes to distribute current. 

Moreover, phosphonium halides can be used as an interfacial n-dopant to improve the electrical properties of cathode contacts. Perovskite solar cells incorporating organic halides as processing additives and interfacial modifiers show significant device performance improvement. 

Fig. 1 Cross section of a standard cell (1) anode channel (2) cathode channel (3) cooling channel (4) gas-diffusion layer (5) membrane (6) cathode contact area (7) anode contact area (8) hydrogen diffusion length at the channel (9) hydrogen diffusion length at the contact area (10) oxygen diffusion length at the channel (11) oxygen diffusion length at the contact areas (12) water diffusion length at the channel (13) water diffusion length at the contact areas...

Fig. 6 Cross section of a cell with a porous gas distribution structure (1) anode channel (2) cathode channel (3) cooling channel (4) gas-diffusion layer (5) membrane (6) cathode contact area (7) anode contact area...

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