Abstract
Organic light emitting diode (OLED) can be applied to high quality displays and solid-state lightings due to its self-luminous, low-power consumption, wide-viewing angle, lightness, thinness and flexibility. However, to make products more energy-efficient and with longer lifetime, high efficiency OLED research and development are critical. Besides developing new materials or changing device structures, modification can also be achieved by using additive elements. In this study, we incorporated gold nanoparticles into OLEDs, which notably improved the efficacy and the maximum brightness of green and blue devices. For example, the efficacy at 1,000 cd/m2 increases 24.8% (29.0→36.2 lm/W) and 35.0% (6.0→8.1 lm/W) while the max brightness increases 29.3% (21,500→27,800 cd/m2) and 24.3% (7,800→9,700 cd/m2) for green and blue device. These improvements may be attributed to the current density enhancement due to the incorporation of gold nanoparticles that strengthen the carrier injection. In addition, the use of nanoparticles has following advantages: (1) It is added in non-emissive layer, thus it can be applied to either phosphorescence or fluorescence devices with different colors. (2) Its wet-processable characteristic provides competitive potential for low cost and large area production.