Highly efficient phosphorescent polymer OLEDs fabricated by screen printing

摘要

We demonstrate the use of screen printing in the fabrication of highly efficient phosphorescent polymer organic-light-emitting devices (OLEDs) based on a green-emitting Ir(ppy)_3 and a host polymer PVK. We incorporate PBD in the polymer host as an electron-transporting dopant and a-NPD as a hole transporting dopant. The best screen printed single-layer device exhibits very high peak luminous efficiency of 63 cd/A at a relatively high operating voltage of 17.1 V at the luminance of 650 cd/m~2. We observed the highest luminance of 21,000 Cd/m~2 at 35V. Due to the high operating voltage, despite of the high peak luminous efficiency the peak power efficiency was found to be 12.2 Im/W at the luminance of 470 cd/m~2 (15.9 V).