Origin of enhanced electrical and conducting properties in pentacene films doped by molybdenum trioxide

Molybdenum trioxide (MoO3) doped organic semiconductors have shown attractive applications in organic electric devices. The authors carried out an investigation on the origin of enhanced photoelectric characteristics in MoO3-doped pentacene films. Electrical properties including charge transport, trap density and conductivity in bulk MoO3-doped pentacene films were investigated through fundamental measurements of current-voltage characteristics. Electrical structure and conducting mechanism in MoO3-doped pentacene films were further evaluated by X-ray diffraction and X-ray photoelectron spectroscopy measurements. The experimental results suggest that the improved conductivity in MoO3-doped pentacene film was partly associated with the increased ratio of low Mo oxidation state (Mo4+) with a fact of better conducting property of MoO2 than that MoO3. (C) 2013 Elsevier B. V. All rights reserved.