High contrast green OLEDs using inorganic metal multi layer

Green organic light-emitting diode (OLED) was fabricated using metal–inorganic–metal multi layer composed of thin Al, KCl and thick Al for achieving high contrast without polarizer. The ambient light reflection of OLED using inorganic metal multi layer, polarizer and conventional metal layer are 28.8, 26.9, and 82.1%, respectively. However, OLED with inorganic metal multi layer has high luminescence of 7367 cd/m2, luminous efficiency of 1.81 cd/A at 8 V, and power efficiency of 0.91 lm/W at 5.5 V whereas OLED with polarizer has 6919 cd/m2, 1.03 cd/A at 8 V, and 0.56 lm/W at 5.5 V each. The optical interference effect of inorganic metal multi layer showed possibility of replacing current polarizer to obtain higher contrast ratio in OLED.