The Effect of the Ambient Gases on the Surface Photocurrent in Anthracene

Following the observation that the photocurrent in anthracene is markedly affected by an atmosphere of oxygen over the system, the behavior of anthracene in the presence of atmospheres of other gases has been investigated. The effect has been shown to be confined to the surface photocurrent, and the active gases have been shown to fall into two classes: (1) gases which are electron acceptors, e.g. BF3, HCl, O2, and NO, which all increase the photocurrent markedly; (2) gases and vapors which are electron donors, e.g. NH3, (CH3)2O, and (CH3)3N, which all decrease the photocurrent markedly. The effect of the pressure of the ambient gas and of the temperature of the system on the photocurrent has also been investigated.