Simple formation method of vanadium oxide films with gap states for application in organic optoelectronics

Abstract

The simple and cost-effective method to form vanadium oxides (VOx) with high density of gap-states and role of gap-states for organic electronics were investigated. The percentage of V2O5 decreased from 82.7% to 29.3% as the deposition rate increased from 0.1 to 1.0 angstrom/s in thermal evaporation. Synchrotron radiation photo emission spectroscopy revealed that a number of gap states relating to oxygen vacancies was induced near the Fermi level, transporting charges and lowering the hole injection barrier from 0.92 to 0.67 eV. As a result, the operation voltage at 1 mA/cm(2) was reduced from 8.3 to 5.2 V (C) 2014 Elsevier B.V. All rights reserved.