Synthesis and characterization of molecular semiconductors based on aromatic diamines with various electron acceptors

The synthesis, spectral, electrical and magnetic properties of charge transfer materials of aromatic diamines namely benzidine (BEN) andρ-toluidine (O.TOL) with various acceptors such as iodine, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), tetracyanoquinodimethane (TCNQ), andp-chloranil (p-CA) have been reported. These materials excepto-toluidine-chloranil complex have been found to be typical molecular semiconductors on the basis of temperature dependence on their electrical conductivity. They have low electrical conductivities and two thermal activation energies indicating mixed conductivity mechanism in which both the electrons and holes are charge carriers, one dominating over the other at different temperatures. The observation of the metal like electrical conductivity i.e. the increase of electrical conductivity with decreasing temperature in theo-toluidine-chloranil system is unique for this class of molecular electronic materials.