Abstract
Organic light-emitting diodes (OLEDs) have great potential on lighting application. OLED panels has been commercialized with high cost partly due to the vacuum deposition process. In order to reduce the process cost, solution process is expected to be applied on OLED fabrication. Therefore, researches on solution-processed OLEDs have received extensive attention to meet the market demands. The main purpose of this research is to analyze the factors that would influence the performance, including efficiency and lifetime, of OLED lighting devices. The green phosphorent OLED devices with 0.25 cm2 emissive area were fabricated and the organic layers except electron transport layer were produced by spin coating as test samples. In the OLED devices with three organic layers, the power efficiency at the luminance of 3000 cd/m2 reached 6 lm/W with operating voltage at about 8 V. The lifetime with the initial luminance of 3000 cd/m2 is increased from less than 0.5 hr to more than 20 hr. The morphology of the organic thin films was considered to be the key factor to influence the device performance, so the analysis on the film surface and the whole layer was carried out. In the devices with four organic layers, the power efficiency at the luminance of 3000 cd/m2 reached 11 lm/W with operating voltage less than 7 V. The lifetime with the initial luminance of 1000 cd/m2 is increased to more than 260 hr.