Mechanisms of injection enhancement in organic light-emitting diodes through insulating buffer

摘要

Three types of organic light-emitting diodes are fabricated. Tris-8-hydroxyquinoline aluminum (Alq_(3)) is used as an electron-transporting layer (ETL) and sodium stearate (NaSt) as an electron-injecting buffer. The optimal thickness of NaSt for electron injection is different for cathodes of different metals, such as Mg, Al, and Ag. This is attributed to the different work functions of cathodes, which result in different initial barrier heights for electron injection from cathodes into ETL, and explained based on tunneling theory.