Electrical Conductivity of Organic Semiconductors

This chapter describes electrical conductivity of organic semiconductors. The semiconductive properties of organic compounds are especially interesting, for first of all, they are molecular crystals; this is the essential point that distinguishes the organic semiconductors from the usual inorganic ones. Second, they are synthetic compounds; many varieties of electronic properties can be expected in association with the possible molecular structures. The primary objective of the investigation is to find the characteristics of molecular structure, which contribute to the semiconductive properties. Third, the semiconductive properties of organic compounds should be important for the phenomena of energy transfer in some chemical reactions, especially with regard to biochemical processes. However, this topic is very complicated and may be regarded to lie out of scope of the present survey. Although the number of investigations in this field is increasing progressively, and a considerable number of studies have been carried out using several experimental techniques, there are still substantial fluctuations in the results observed by different investigators.