Improving the efficiency of OLEDs by utilizing Metallophthalocyanines

Abstract

In this paper, the effects of hole injection layer (HIL) on the performance of typically used tris-(8-hydroxyquinoline) aluminum (Alq3) based OLEDs have been investigated. Three different HIL materials were used: copper phthalocyanine (CuPc), magnesium phthalocyanine (MgPc) and zinc phthalocyanine (ZnPc). The Metallophthalocyanines (MPcs) will be used to construct single hole injection layer (HIL) and double HIL (d-HIL). In the OLEDs, Alq3 acts as the emitting layer and electron transport layer. Although d-HIL structures show higher efficiency than that of the reference device, the highest current efficiency ∼ 4.02 cd/A corresponds to the 15 nm ZnPc HIL device. Compared to an current efficiency of ∼ 3.29 cd/A and a power efficiency of ∼0.99 lm/W (at 100 cd/m2 luminance) of the reference device, an 15 nm ZnPc HIL device has ∼22% higher current efficiency and ∼67% higher power efficiency. The reasons for the improvements will be discussed.