Top-emitting organic light-emitting device with high efficiency and low voltage using a silver–silver microcavity

Top-emitting organic light-emitting devices (TOLEDs) with high efficiency and low driving voltage using silver–silver microcavity structure were demonstrated. With tris(8-hydroquinoline) aluminum as emission layer, the Ag–Ag based TOLED showed a maximum luminous efficiency of 9.21 cd/A which was much higher than conventional Ag–Al/Ag based TOLED (4.21 cd/A) and corresponding bottom-emitting OLED (3.77 cd/A). The Ag–Ag based TOLED also exhibited low driving voltage and thereby an enhanced power efficiency of 4.25 lm/W (at 40 mA/cm2). The excellent performance of Ag–Ag based TOLED was attributed to the significant microcavity effect and efficient carrier injection from Ag electrode.