Energy Gap of the Crystalline Anthracene

Abstract

The DC-photoconduction of both pure and heavily tetracene doped anthracene single crystals has been investigated in both the strongly and weakly absorbing wavelength regions. With sandwich-type cell and under monochromatized illumination, the electron photocurrent (i₋) and hole photocurrent(i₊) were measured separately. With doped crystals, the current produced by the thermal excitation from the tetracene excited state could be measured for various temperature regions. The thermal activation energy for carrier generation from the tetracene excitation state was measured to be 0.35 eV for i₊ and 0.24 eV for i₋. As the excited state of tetracene included is 2.4 eV from the ground state, energy gap of crystalline anthracene was deduced to be 3.0 eV.