High-quality thin-film passivation by catalyzer-enhanced chemical vapor deposition for organic light-emitting diodes

The thin-film passivation of organic light-emitting diodes (OLEDs) by a SiNx film grown by catalyzer-enhanced chemical vapor deposition was investigated. Using a tungsten catalyzer connected in series, a high-density SiNx passivation layer was deposited on OLEDs and bare polycarbonate (PC) substrates at a substrate temperature of 50 degrees C. Despite the low substrate temperature, the single SiNx passivation layer, grown on the PC substrate, exhibited a low water vapor transmission rate of (2-6)x10(-2) g/m(2)/day and a high transmittance of 87%. In addition, current-voltage-luminescence results of an OLED passivated with a 150-nm-thick SiNx film compared to nonpassivated sample were identical indicating that the performance of an OLED is not critically affected by radiation from tungsten catalyzer during the SiNx deposition. Moreover, the lifetime to half initial luminance of an OLED passivated with the single 150-nm-thick SiNx layer was 2.5 times longer than that of a nonpassivated sample.