Cathodes, photo

Cathodic photo-currents observed during the deposition of CdTe have been interpreted as evidence for p-type conductivity [90]. Verbrugge and Tobias [91] showed... 

Non-uniformity of composition sometimes can be exploited to advantage, e.g., in observing work function changes at a series of compositions, a sliding cathode photo tube (41), Fig- 4, was used. A curved substrate, either cylindrical or spherical, can also be used in preparing specimens with a broad range of concentrations (42) ... 

FIGURE 22.22 Polarization curves for localized corrosion of a photoexcited p-n heterojunction electrode of GaAs in 0.5 kmol m-3 sulfuric acid solution [15] ta(ph) = anodic photo-dissolution current and lc(ph) = cathodic photo-hydrogen current. 

Generally, the semiconductors are protected against cathodic (photo)corrosion in indifferent electrolytes because of the formation of a thin metallic film produced at the first instant of (photo)corrosion by the (photo)electrons, which for GaAs, for example, can be written as... 

Spiral-wound EDI with central cathode. Photo of OmexeU spiral-wound EDI (SWEDI)... 

A role is also played by the temperature and frequency dependence of the photocurrent, the variable surface sensitivity at various parts of the cathode and the vector effect of polarized radiation [40]. All the detectors discussed below are electronic components whose electrical properties vary on irradiation. The effects depend on external (photocells, photomultipliers) or internal photo effects (photoelements, photodiodes). 

Dominey RN, Lewis NS, Bruce JA, Bookbinder DC, Wrighton MS (1982) Improvement of photoelectrochemical hydrogen generation by surface modification of p-type silicon semiconductor photo-cathodes. J Am Chem Soc 104 467 82... 

In the presence of sulfite anions and absence of oxygen, CdS sols undergo photo-cathodic dissolution... 

Lee et al. [30] used in situ X-ray photo electron spectroscopy (XPS) measurement on La0 9Sr0 Mn03 as a function of cathodic polarization. The XPS results showed the peaks of Mn 2p spectra were shifted to the lower binding energy as the applied potential became more cathodic, indicating the reduction of Mn ions. The oxygen reduction and the concomitant formation of Mn2+ ions and oxygen vacancies are proposed as ... 

On the other hand, the stability of the dialkylfluorene moiety to photo- and electrooxidation cannot be postulated as well. The n-doping of PF (chemically from Ca cathode, or... 

FIGURE 6.24 (a) Luminous efficiency of two top-emitting OLEDs with a configuration of glass/Ag (200 nm)/ITO (130 nm)/PEDOT (80 nm)/Ph-PPV (80 nm)/semi transparent cathode (closed circles), and Al-PET/acrylic layer/Ag (200 nm)/CFx (0.3 nm)/Ph-PPV (110 nm)/semitransparent cathode (open diamonds), (b) A photo image showing a flexible top-emitting electroluminescent device on an Al-PET substrate. 

This method is similar to continuous flow method except that the rate of flow is continuously varied and the analysis is made at a fixed point along the observation tube. Since the rate of flow changes with time, the reaction mixtures arriving at observation point have different time. In the accelerated flow method the output from a photo electric colorimeter is fed to a cathode-ray oscilloscope, which sweeps out a complete time-concentration record which may be photographed. The method is useful for very rapid enzyme reactions and requires only small quantities of reactants. 

Photoemissive tubes are necessary for work in the ultraviolet range and they show greater sensitivity and precision than photoelectric cells. A simple photo-emissive tube consists of two electrodes in a vacuum. A silver cathode coated with an alkali metal is maintained at a potential difference of about 100 V from the anode, which is a plain silver wire and serves to collect the electrons (Figure 2.26(a)). 

The photoelectrolytic cell can be composed of both a photoexcited n-type anode and a photoexcited p-type cathode here, the anode and cathode can be the same semiconductor or different semiconductors. The energy diagrams for a photo-electrol3 c cell of an n-type anode and a p-type cathode of different semiconductors are illustrated in Fig. 10-30. 

Gentlemen, I took my double coil (the one in the photos section) and placed an old SPRAGUE BUFFER (.002-16,000 volt) capacitor from the top of the plug to the base., cathode to hot. (part number MD-D2). It increased a Sms spark from a 20,000 volt Chevy coil so much that it screeches when it fires. Very bright. Haven t tried it in the motor yet but I thought it was significant enough to mention. If you wind a coil like this make sure you wind both layers in the same direction. There may well be a better ratio of turns and a better way to amplify this. I just used a coil which I had already made. 

Intermolecular addition of radicals, generated by photo-electrochemical catalysis, to activated alkenes can also be brought about. The reaction of 66 is used as a key step in one synthesis of the insect pheromone, brevicomin [219]. The reaction of a secondary radical from 67 occurs at low cathode potentials and without photochemical assistance [219]. This illustrates the equiibrium between a secondary al-kylcobalt(m) species and the radical - cobalt(ii) pair. The carbon radical is eventually captured by reaction with the alkene. Further steps in the synthesis lead to four isomers of the pheromone, multistriatin, each of which is a pure enantiomer since... 

In fact, in 1972, Fujishima and Honda (10) demonstrated that O2 evolution on n-type Ti02 occurs as a photocurrent, proportional to the light intensity (Figure 1) of wavelengths less than 415 nm, i.e. for photon energies equal to or greater than the band gap of Ti02 3.0 eV. In this work and that of Ohnishi et al. (11) a platinum black metal cathode was connected in an external circuit to an indium contact on the back side of the photo-anode (see... 

Figure 2). Hydrogen was evolved at the cathode, the over-all process being the decomposition of water. This process, involving an applied potential difference between the anode and cathode, we shall refer to as photo-assisted electrolysis.

Photo-electrolysis Without Applied Potential Using n-type Anode and Metal Cathode... 

In Figure 16 is shown the photo-current / potential relation for an n-type GaP anode and a p-type GaP cathode. The current at zero applied potential is larger in this case, but this is because the anodic reaction is dissolution of the GaP and not oxygen evolution. 

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