Combined Dopant

Ke rwords Stabilized Zirconia/Solid State Fuel Cell/Thermal Stability/Combined Dopant/... 

Yang and coworkers [35, 897-899] performed detailed studies of the electro-chromism of P(ANi) in liquid and solid electrolytes, with polymeric and other dopants, and in multilayer systems. They monitored effects of variables such as pH, film thickness, multilayer configuration and combination dopants. Again, however, few of these studies, at least in the public domain, described actual, working devices, as opposed to laboratory studies in electrochemical cells. 

PPQs possess a stepladder stmcture that combines good thermal stabiUty, electrical insulation, and chemical resistance with good processing characteristics (81). These properties allow unique appHcations in the aerospace and electronics industries (82,83). PPQ can be made conductive by the use of an electrochemical oxidation method (84). The conductivities of these films vary from 10 to 10 S/cm depending on the dopant anions, thus finding appHcations in electronics industry. Similarly, some thermally stable PQs with low dielectric constants have been produced for microelectronic appHcations (85). Thin films of PQs have been used in nonlinear optical appHcations (86,87). 

Intensive research on the electrocatalytic properties of polymer-modified electrodes has been going on for many years Until recently, most known coatings were redox polymers. Combining redox polymers with conducting polymers should, in principle, further improve the electrocatalytic activity of such systems, as the conducting polymers are, in addition, electron carriers and reservoirs. One possibility of intercalating electroactive redox centres in the conducting polymer is to incorporate redoxactive anions — which act as dopants — into the polymer. Most research has been done on PPy, doped with inter alia Co 96) RyQ- 297) (--q. and Fe-phthalocyanines 298,299) Co-porphyrines Evidently, in these... 

Instead of applying synthetic methods to alter chromophore reactivity, this new way of controlling chemical reactivity involves choosing an appropriate solid micellar system (from the available multitude) and exploiting it to manipulate the chemistry of the entrapped compound. The sol-gel matrix and the micellar solubilization, in fact, have a synergetic effect. Their combination produces effects stronger and more tuneable than in solution, so that a careful selection of sol-gel entrapped surfactants allows one to induce enormous changes in the dopant properties. 

The LEC structure that involves the addition of ionic dopants and surfactants to the printable inks enables the ability to print a top electrode without restriction by the work function of the metal. Silver, nickel, or carbon particle-based pastes are generally the preferred printable electron injecting electrodes however, the shape and size of the particles combined with the softening properties of the solvent can create electrical shorts throughout the device when printed over a thin polymer layer that is only several hundred nanometers thick. For optimal performance, the commercially available pastes must be optimized for printing onto soluble thin films to make a fully screen-printed polymer EL display. 

In the mechanism illustrated in Figure 6, the combination of the redox and acid properties of the catalyst determines the relative contribution for the formation of MA and PA. It is generally accepted that the higher the crystallinity of the VPP, the more selective to PA is the catalyst (3,4,10-12,17,18). Poorly crystalline VPP, like that one formed after the thermal treatment of the precursor (especially when it is carried out under oxidizing conditions), is selective to MA, but non-selective to PA. On the contrary, a fully equilibrated catalyst, characterized by the presence of a well-crystallized VPP, yields PA with a good selectivity. The presence of dopants that alter the crystallinity of VPP may finally affect the MA/PA selectivity ratio (19). Moreover, the surface acidity also influences the distribution of products (17) an increase of Lewis acidity improves the selectivity to PA, while that to MA is positively affected by Bronsted acidity (2). 

Direct observation of point defects in metals has been possible by field ion microscopy. Impurity point defects may be usefully investigated by electron microscopy in combination with electron diffraction and electron spectroscopy. Direct observation of the dopant environment in fluorites has been attempted by Catlow et al. (1984) by employing EXAFS in conjunction with computer simulation. 

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