Semi- and Photo-conductivity of Molecular Single Crystals. Anthracene and Pyrene

The electrical resistivity and photoconductivity of single crystals—anthracene and pyrene—, which could be grown by slow evaporation of a solvent over a month in Solvesso, were measured. The temperature dependency of electrical resistivity (ρ) has been expressed by the next formula, ρ=ρ0 exp (Δε⁄2kT), and the values of resistivity (ρaT 15°) and thermal activation energy (Δε) are 1022Ω cm., for anthracene and 1020Ω cm., 2.4 eV. for pyrene. This activation energy and the longest wave edges of absorption spectra in the solid state coincided with each other, then this phenomenon will be due to the fact that molecular single crystals are intrinsic semi-conductors as in the case of powdered form.