Defects of Passivation Films for Color-Filter-Based OLED Devices: Effects on Dark Spot Formation

Abstract

The color filter (CF)-based organic light-emitting diode (OLED) devices suffer dark spots due to remaining moisture in the CFs. A passivation film is thus used to prevent this remaining moisture from reaching the OLED. The characteristics of defects in passivation films and their effects on dark spot formation in OLED devices were investigated. The structure of the sample devices were CF /over coat (OC) passivation film by sputtering /indium-tin-oxide (ITO) anode /OLED/Al cathode , fabricated on glass substrates. The defects of passivation films caused dark spots in the OLED devices. These defects can be classified as particulate and nonparticulate. The particulate defects can be further classified as typical pinhole defects resulting from large particles (micrometer order size) and as defects with a characteristic explosive shape resulting from small particles (submicrometer order). The explosive degradation of the films may be due to the gasification of localized moisture. Nonparticulate defects consist of microvoids formed at the OC-passivation film interface. The surface treatments, such as “light-ashing” and “ion-cleaning” done on the OC surface are largely responsible for these microvoids.