Hybrid Passivation for a Film-like Organic Light-Emitting Diode using Parylene and Silicon Dioxide

A hybrid passivation method a using parylene and silicon dioxide combination layer for a film-like organic light-emitting diode (OLED) was applied on a polycarbonate substrate. Parylene coating by vapor polymerization is a highly effective passivation process for the OLED, and it is applied to the entire top surface and the edges of the OLED device. To minimize the permeation of moisture and oxygen from the top surface of the device, an additional layer of silicon dioxide was deposited over the parylene-coated layer. It was found that the water vapor transmittance rate (WVTR) of parylene (15 µm in thickness)/SiO2 (0.3 µm in thickness) combination layers deposited on the polycarbonate film was decreased to less than 10-3 g/(m2d). The OLED that had undergone hybrid passivation showed significantly longer lifetime characteristics in ambient conditions than the non-passivated OLED. The lifetime of the passivated OLED was 400 h and it was more than ten times the lifetime of the conventional non-passivated OLED.