Patent ID: 7075231
Filing Date: 2006-07-11
Classification: C09K,H01L

Abstract:
1. A tandem OLED comprising: a) an anode; b) a cathode; c) at least two electroluminescent units disposed between the anode and the cathode, wherein each of the electroluminescent units includes at least one hole-injecting layer, one hole-transporting layer, one organic light-emitting layer, one electron-transporting layer, and one electron-injecting layer; d) at least one intermediate connector, wherein each of the intermediate connectors includes at least one layer, and wherein each of the intermediate connectors is disposed between electroluminescent units; and e) wherein the thickness of each layer in each of the electroluminescent units and the intermediate connectors is selected to provide high luminous efficiency using optical out-coupling while satisfying the test condition that the voltage drop from the anode to the cathode is less than 4.0 V×N (the number of electroluminescent units) at 20 mA/cm