Copper phthalocyanine electrical conductivity

The reddish metal was already known in prehistoric times. It occasionally occurs as a native metal, but mostly in conspicuous green ores, from which it is extracted relatively easily. It is convenient to work, but not very hard. Not very optimal as a tool ("Otzi the Iceman" had a copper axe with him). Only through the addition of tin is the more useful bronze obtained. Its zinc alloy is the versatile and widely used brass. Copper is one of the coinage metals. Water pipes are commonly made of copper. Its very good thermal and electrical conductivity is commonly exploited (cable ), as well as its durability (roofs, gutters), as the verdigris (basic copper carbonate) protects the metal. Cu phthalocyanines are the most beautiful blue pigments. Seems to be essential to all life as a trace element. In some molluscs, Cu replaces Fe in the heme complex. A 70-kg human contains 72 mg. 

The mechanism of film growth of 56 was discussed in [240,250]. After formation of the first few layers of polymeric phthalocyanines, copper atoms diffuse from the copper film to the growing polymer film surface in order to react with 1,2,4,5-tetracyanobenzene at first to octacyanophthalocyanine and then to oligomeric and polymeric phthalocyanines. By ESCA spectra 0.7% of free Cu in the polymeric films were found. In dependence of the deposited Cu-film thicknesses of 1.5 till 20 nm adhering films of the polymers 56 with thicknesses of 46 till 230 nm were obtained For the ratio of the thickness of the polymer film to the copper film in every case an average value of --25 was determined. The films exhibit good electrical conductivities. 

The columnar phases of metallomesogens have the electrical properties of molecular semiconductors [77-84]. Figure 22 presents the Arrhenius plots of the a.c. conductivity (unaligned samples of copper phthalocyanines (13) determined by Van der Pol et al. [83]. The conductivity increases with increasing temperature. The activation energy is approximately 0.5-0.6 eV at 175 °C for the compounds 13 with R=0C8H 7 and OC12H25. 

Polymers that are closely related to the metal phthalocyanines have been prepared from 2,3,4,5-tetracyanothiophene and 2,3,4,5-tetracyanofuran 52, 53). Polymerization with copper acetylacetonate in bulk or in cyclohexanone solution gave polymers whose electrical conductivities ranged from 5 x lO to 8 X 10 ohm cm . ... 

Asymmetrically substituted phthalocyanines have been studied, which are expected to have better characteristics in monolayer formation and the deposition process compared wifti symmetrical substituted materials. For example, copper tris(CH2NHCH)-(CH3)2)phthalocyanine is deposited in a Y type manner to form semiconducting LB films without matrix molecules [217]. LB films of phthalocyanines wifti more complicated structure have also been reported (Figure 14.31) [218-220]. The electrical conductivities of these LB films showed a power-law dependence with frequency in a.c. measurement, which was explained in terms of bipolaron hopping. An attempt at the application of these film to toluene sensors was carried out [221]. 

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