Gallium based materials

Note that a five-layer solar-cell is proposed. However, cost-considerations may make this type of solar cell impractical since the cost of electricity will be too much. A three-layer type of solar-cell has been built which had an efficiency of about 39% (consisting of Si, GaAS and GaN). But until the price of other energy sources mount, or until the cost of gallium-based materials drops, a layered solar-ceU will not be economically feasible. 

We have developed a systematic study of quaternary chalco-gallates, indates (trielates) and chalco-silicates, and germinates (tetrelates) of the rare-earth metals. We have demonstrated that a series of new compounds could be formed in these families of materials [1, 3, 9, 10, 14, 81, 82]. There have been reports in the literature of a few examples of these types of materials, but there is sufficient evidence to support the fact that this area is wide open for exploring the likelihood for new rare-earth metal-based materials [83-90]. Our studies have focused on the gallium, indium, germanium and sihcon sulfides, selenides, and teUurides. 

The one-dimensional framework solids constitute a very small fraction of the gamut of structures known in phosphate-based materials. The existence of one-dimensional structures, however, has been known for some time in the case of aluminum, gallium and zinc phosphates [13-16]. The structures consist of polymeric chains of [MP208]" units supported by the structure-directing... 

Dunne SM, Abraham R. Dental post-operative sensitivity associated with a gallium-based restorative material. Br Dent J 2000 189(6) 310-13. 

Both gallium (Ga) and mercury (Hg) can be eliminated from consideration as base materials just based on their low melting points. The melting point of the elements Ag, Cu, Ni, and Au are too high to serve as base materials and some are also too expensive, only leaving In and Sn. Indium is too expensive to use in quantities required of a base alloy. That leaves Sn, whose solder alloy melt points are typically between about 120°C and 280°C, providing a baseline for lead-free solder alternatives to eutectic Sn-Pb. Eutectic alloys with either Cu or Ag have melt points close to pure Sn, so only a few percent of these elements can be added to Sn before the melting point level is considered unacceptable [31]. 

Since ionic radii and valences of iron and chromium ions are similar to gallium ion, substitution of these cations with gallium ion may result in powders with similar crystal structure and properties to LSGM. Moreover, LaFe03- and LaCr03-based oxides are candidate cathode and anode materials for SOFC, respectively. 

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