An efficient organic light-emitting diode with silver electrodes

An efficient top-emitting organic light-emitting diode (OLED) was formed of an organic stack sandwiched between a thick Ag anode and a semi-transparent Ag cathode. Interface modification was employed to reduce the injection barriers for both electron and hole from the Ag electrodes into the organic stack. The OLED exhibited superior current-voltage characteristics over a control device having an anode of indium tin oxide. The color could be tuned by varying the thickness of the organic stack. At a thickness of 105 rim, the OLED showed a narrow green emission peak with a device efficiency of about 7.64 cd/A, much greater than 3.36 cd/A obtained from the control device. The color tuning and the efficiency enhancement are attributed to the formation of an optical microcavity in the OLED with Ag electrodes. (C) 2004 Elsevier B.V. All rights reserved.