Photoconductivity of the charge transfer complex crystals. Anthracene-Dimethylpyromellitimide

Abstract

An investigation is made of the mechanism of photoconductivity of needle-shaped single crystals of a weak charge transfer complex formed by anthracene and dimethylpyromellitimide. In the crystals of the charge transfer (CT) complex, the annihilation of triplet excitons is shown to generate charge carriers. The contribution of this process to the photoconductivity is evaluated. The photoconductivity of the CT-complexes is found to exhibit a sensitivity toward weak external magnetic fields as a result of the variations in the rate constants of triplet-triplet annihilation and intersystem crossing in excited states of the CT-complex. A scheme is proposed to represent the processes involving excited and ionized states in the crystals of the anthracene-dimethylpyro-mellitimide CT-complex.