Inorganic dopants

The low-temperature processing conditions required for the fabrication of these new composite materials permits the incorporation of organic molecules, such as laser dyes, as well as inorganic dopants, such as lanthanide ions [44-49]. In Fig. 9, the processing procedure for fabricating organic dye-doped gel-polymer composites is outlined. Because the composite is comprised of two phases, both of which are derived from solution, the organic dye can be incorporated in either the gel phase or the polymer phase [44]. 

E.Y. Voropaeva, EA. Sanginov, V.I. Volkov, A.A. Pavlov, A.S. Shalimov, I.A. Stenina, A.B. Yaroslavtsev, Transport properties ofMF-4SK membranes modified with inorganic dopants, Russ. J. Inorg. Chem. 53 (2008) 1536—1541. 

Briseno and co-workers [24] quantified inorganic dopants in polypyrrole films by a combination of electrochemistry and ICP-AES. 

Reisfeld described the incorporation of fluorescent organic and inorganic dopants in waveguides [213]. Erbium is the most employed element in films [214-216]. Other elements incorporated in inorganic matrices are ytterbium [217-219], neodymium [220], and europium [221]. Other authors combined silver and erbium in the film [222]. The dyes in zirconia-hybrid films was used for laser applications [223]. 

A dopant with a long aliphatic tail embedded in an electrically conductive polymer on electrochemical polymerization make. the polymer mechanically superior to the one with an inorganic dopant. The aliphatic nature of contracting in H2O holds the dopant in the polymer on reduction and brings a small cation into the polymer to neutralize the freed anion. When a large cation is used instead of small one, the redox reaction goes slow. It seems that redox reaction occurs only when the reactive site is electrically balanced. 

The interest of physicists in the conducting polymers, their properties and applications, has been focused on dry materials 93-94 Most of the discussions center on the conductivity of the polymers and the nature of the carriers. The current knowledge is not clear because the conducting polymers exhibit a number of metallic properties, i.e., temperature-independent behavior of a linear relation between thermopower and temperature, and a free carrier absorption typical of a metal. Nevertheless, the conductivity of these specimens is quite low (about 1 S cm"1), and increases when the temperature rises, as in semiconductors. However, polymers are not semiconductors because in inorganic semiconductors, the dopant substitutes for the host atomic sites. In conducting polymers, the dopants are not substitutional, they are part of a nonstoichiometric compound, the composition of which changes from zero up to 40-50% in... 

These and several other researchers extended the methodology with the aim to widen functionality, using dopant molecules and silicon precursors derivatized with organic moities giving place to a vast class of hybrid organic-inorganic organosilica nanocomposites capable to meet numerous, advanced requirements in fields as diverse as catalysis,... 

The spray method was used to produce alumina pigments doped with Cr, Mn, and Co. In these experiments, Al(.vec-OBu)3 was mixed with solutions of the corresponding metal nitrates in. veobutoxide, the resulting liquids were nebulized, and then the droplets were hydrolyzed (76). The major purpose of these studies was to obtain inorganic pigments and to evaluate their color properties by altering the amount of dopants in the aluminum oxide matrix. For the same reason, the vanadium... 

Photovoltaic and photoconductive phenomena for various types of CT complexes between saturated polymers and dopant molecules, heterojunctions between polymers and organic and inorganic photoconductors were also investigated in the last few years [86-92]. The quantum efficiency of the energy conversion of 10-3% was obtained for such systems and output power density of 3 x 102 mV cm-2. The mobilities of the heterogeneous polymer systems with despersed inorganic photoconductors reach the value — 10 3-10-4 m2 V 1s 1. 

The doping procedure is simple and straightforward the host molecule is added to the polymerizing mixture. When the polycondensation is completed, the dopant molecules are entangled in the inorganic polymeric network (Figure 1). 

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