Electrical Properties of Some Charge-Transfer Complexes under High Pressure

The electrical resistances of several polyaromatic—halogen intermolecular charge complexes (pyrene with varying concentrations of bromine, coronene with iodine, and perylene with bromine) were measured at pressures up to 80 kbar. Activation energies as a function of composition were measured for the pyrene·XBr2 samples, as were Seebeck coefficients and activation energies at varying pressures for one of the complexes. The resistance decrease with increasing pressure is interpreted as due to an increase in concentration of charge carriers. Possible states in which the charge carriers exist are discussed.