In this study, OLED using hetero electrode structures have been fabricated to increase luminescence efficiency. Also, the numerical simulation of these fabricated hetero structures has been carried out in order to understand the improvement of efficiency. It was found that numerical analysis about hetero electrode showed an excellent agreement with the experimental result and the presence of a thin layer of Sri or Ag at the organic-aluminum interface enhanced both electron injection efficiency and electroluminescence when compared to OLEDs using homogeneous electrode. (c) 2005 Published by Elsevier B.V.