Multilayer Organic Light-Emitting Diodes with Phthalocyanine Film as Hole-Injection Layer

Abstract Multilayer organic light-emitting diodes (LEDs) with the structure of ITO/PVK/Alq3/Al and ITO/Pc/PVK/Alq3/Al were fabricated. The introduction of the phthalocyanine layer dramatically lowers the turn-on voltage of the devices from 7 V to 3.5 ∼ 4 V, and significantly improves the stability of LED devices due to its high chemical and environmental stability. The device can also bear a much higher current density, up to 3000 A/m2.