Electronic Structures of Iodine‐Doped Lithium Phthalocyanine Crystals

Abstract

The electronic structures and stable doping sites of iodine‐doped lithium phthalocyanine (LiPc) are investigated using a first‐principles calculation based on the density functional theory. It is revealed that the metallic conductivity of highly doped LiPcIx is due to the band originating from the doped iodine, comparing the band structures of several x. It is also revealed that the doped iodines are energetically stable when they are arranged to make a line along the stacking direction that becomes a conducting path. The results well explain the experimental results of the strange dependence of the conductivity of LiPcIx on the doping rate x. These results indicate that there is a new mechanism for the electronic transport of doped organic materials in that the dopant plays the main role, which is completely different from the traditionally accepted partial oxidation theory.