Dependence of dark spot growth on cathode/organic interfacial adhesion in organic light emitting devices

摘要

The growth of dark spots in organic light emitting devices (OLEDs) with cathodes deposited at 65℃ instead of the conventional room temperature deposition, or which contain a metal-organic-mixed layer at the cathode contact, is investigated. The results reveal a strong correlation between the growth rate of dark spots and adhesion at the cathode-organic interface, where stronger adhesion results in a slower growth of dark spots. The findings shed light on the beneficial effect of increasing interfacial adhesion on improving the ambient stability of OLEDs. Measures for increasing cathode-organic adhesion can be expected to be particularly beneficial for flexible OLEDs where device protection from the ambient is more challenging.