Semiconducting Metallic Organic Polymers

The significance of the semiconductivity of organic dyes and other classes of organic solids, such as charge-transfer complexes, which behave in some ways like metals 7> or polymers 8>9>, is to day beyond doubt. The possible industrial applications of this new class of semiconductors are, however, still in the discussion stage. 

In 1977, the first covalent organic polymer, polyacetylene (CH), , that could be doped through the semiconducting to the metallic range, was reported. Another significant breakthrough occurred in 1980 with the discovery that PPP could be doped to conductivity levels quite comparable to those in polyacetylene. This polymer is the first example of non-acetylene hydrocarbon polymer that can be doped to give polymers with metallic properties. 

Results of numerous items of research have shown that, in theory, any material can be used in the design of a gas sensor, regardless of its physical, chemical, structural, or electrical properties (Korotcenkov 2010,2011). Prototypes of gas sensors based on covalent semiconductors, semiconducting metal oxides, solid electrolytes, polymers, ionic membranes, organic saniconductors, and ionic salts have already been tested (Sadaoka 1992 Gopel 1996 Haugen and Kvaal 1998 Monkman 2000 Talazac et al. 2001 Eranna et al. 2004 Adhikari and Majumdar 2004). As shown in Table 1.23, these materials may be used... 

The literature of polyimines is extensive [164-173]. A number of researchers have tried to synthesize high molecular weight polymers but failed due to poor solubility in organic solvents. Polyimines are of great interest because of their high thermal stability [174-176], ability to form metal chelates [174-177], and their semiconducting properties [178-181]. Due to insolubility and infusibility, which impeded characterization of the molecular structure, the application of these polymers is very limited and of little commercial importance. 

---