Effect of low pressure remote plasma treatment on damage reduction of emitting organic layer for top-emission organic light-emitting diodes

Abstract

To study the damage mechanism of an emitting polymer [poly(9,9- dioctylfluorene) (PFO)] during indium tin oxide (ITO) sputtering for top-emission organic light-emitting diodes (TEOLEDs), we treat PFO with low pressure remote RF (LPRF) plasma. The surface energy of PFO is changed by LPRF plasma treatment with the minimum damage condition. By the surface energy control of PFO, the Al metal shows continuous layer growth, which is attributed to the reduction of polymer damage as a buffer layer. From the results of light-current-voltage (L-I-V) characteristics and photoluminescence (PL) measurement, the main factors of polymer damage are both the energetic particles such as Ar neutral atoms and negative ions and the photo oxidation of emitting polymer. We discuss the damage mechanism during sputtering and characterize electronic energy level of the damaged PFO layer. © 2006 The Japan Society of Applied Physics.