The photoconduction threshold in anthracene single crystals

Abstract

We report the excitation spectrum for intrinsic photoconductivity measured with unpolarized light incident on the 001 face of an anthracenesingle crystal. Over the photon energy range 3.75 to 4.4 eV, the room temperature (near 295 K) quantum yield of free carriers rises by a factor of 103. The activation energy for free carrier production rises steeply between 3.87 and 4.06 eV and then levels off. These results are compared with recent work by Lyons and Milne and some discrepancies are noted.