Electron Spin Resonance in Complexes of Aromatic Hydrocarbons with Iodine

Abstract

Accurate measurements of electron spin concentration in semiconducting molecular complexes of perylene and pyrene with iodine have indicated an exponential temperature dependence in excellent agreement with the activation energy for electronic conduction. The agreement of the magnitudes of the spin concentrations with the carrier concentration estimates obtained from electrical measurements further confirms the identification of the unpaired spins as charge carriers. At low temperatures, small temperature-independent concentrations of trapped spins or free radicals are observed. Spin resonance line shapes, relaxation times, and g-factor anisotropies also have been determined.