Improved electron injection in spin coated Alq_3 incorporated ZnO thin film in the device for solution processed OLEDs

摘要

We deposit tris-(8-hydroxyquinoline)aluminum (Alq_3) incorporated zinc oxide (ZnO) thin films by spin coating method under the normal ambient. It showed the higher transmittance (90% at 550 nm) when compared to that (80% at 550 nm) of spin coated pure ZnO film. SEM studies show that the Alq3 incorporation in ZnO film also enhances the formation of small sized particles arranged in the network of wrinkles on the surface. XRD reveals the improved crystalline properties upon Alq3 inclusion. We fabricate the electron-only devices (EODs) with the structure of ITO/spin coated ZnO:Alq3 as ETL/Alq3 interlayer/LiF/Al. The device showed the higher electron current density of 2.75 mA/cm~2 at 12V when compared to that (0.82 mA/cm~2 at 12V) of the device using pure ZnO ETL. The device results show that it will be useful to fabricate the low-cost solution processed OLEDs for future lighting and display applications.