Conductivity and Thermoelectric Potential Measurements on Perylene:Metal Halide Complexes

Abstract

The conductivities and Seebeck coefficients of a series of perylene complexes with metal halides from groups II B, III A, IV A, V A, V B, VI B, VII A, and VIII of the periodic table have been studied to determine possible dependence of these properties on the nature of the halide. No direct correlation was found between conductivity and position on the periodic table. The complexes having a conductivity of >10−5 mho/cm ( InCl3 , PCl3 , FeCl3 , ICI , SbCl5,I2 ) were black in color; none of the others were black. Activation energies were measured for materials having a conductivity >10−11 mho/cm and were 0.60 ev or lower. There was an approximate straight line relationship between the log conductivity and the activation energy, indicating that conductivity for the series is determined primarily by the number of thermally activated carriers rather than by the reservoir of available carriers in lower energy states. As a rule the most conductive materials had the lowest Seebeck coefficients. It was found that perylene: FeCl3 could be prepared as either p‐ or n‐type depending on the initial reactant ratio, with the perylene‐rich material showing p‐type properties.