Passivation of organic light-emitting diodes with aluminum oxide thin films grown by plasma-enhanced atomic layer deposition

The passivation of organic light-emitting diodes (OLEDs) with Al2O3 films containing small amounts of N (Al2O3:N) was investigated by plasma-enhanced atomic layer deposition using a direct rf plasma with a short pulse time. Luminance-voltage and current density-voltage curves of an OLED passivated with a 300 nm Al2O3:N film at 60 degreesC remained unchanged compared to those of nonpassivated OLED and 96% of the initial luminance were maintained even after operating for 850 h at 14 mA/cm(2). The lifetime of an OLED with an 80 degreesC Al2O3:N film was 650 h, 6.2 times longer than that of a nonpassivated sample, although the luminance-voltage characteristics of the OLED were altered to a considerable extent. (C) 2004 American Institute of Physics.