By metathesis between lithium salts of 7,7,8,8-tetracyano-p-quinodimethane and 1-methyl-3-alkylimidazolium bromides, simple radical salts were prepared whose specific electrical conductivity values are c. 10-7-10-3, Ω-1 m-1, according to the donor structure. Combining these salts with neutral 7,7,8,8-tetracyano-p-quinodimethane (TCNQ°) gave complex salts with an electrical conductivity higher by 7-3 orders of magnitude which increase monotonically with increasing volume of the alkyl group. The compounds are stable in anhydrous conditions also in presence of oxygen, and if irradiated by daylight. The rate constant of hydrolysis of these salts is proportional to the water content in solution and inversely proportional to the content of neutral TCNQ° in the simple radical salt. The hydrolysis is predominantly activated by light absorbed by the decomposition products.
Electrical Conductivity of Doped Organic Semiconductors Limited by Carrier–Carrier Interactions
