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 Si Nx film grown by catalyzer-enhanced chemical vapor deposition was investigated. Using a tungsten catalyzer connected in series, a high-density Si Nx passivation layer was deposited on OLEDs and bare polycarbonate (PC) substrates at a substrate temperature of 50 °C. Despite the low substrate temperature, the single Si Nx passivation layer, grown on the PC substrate, exhibited a low water vapor transmission rate of (2-6) × 10-2 g m2 day and a high transmittance of 87%. In addition, current-voltage-luminescence results of an OLED passivated with a 150-nm -thick Si Nx 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 Si Nx deposition. Moreover, the lifetime to half initial luminance of an OLED passivated with the single 150-nm -thick Si Nx layer was 2.5 times longer than that of a nonpassivated sample.