We present solution-processable electron-transport layers (ETL) with highly enhanced electron-injection and electron-transport properties and resistance to oxygen and moisture for solution-processed organic light-emitting diodes (OLEDs). We selected polyethyleneimine ethoxylated (PEIE) as the ETL and Cs2CO3, CsF, and tris(8-hydroxyquinolinato)aluminum (Alq3) as n-type dopants. Compared with OLEDs with undoped PEIE as the ETL, the OLEDs with doped PEIE (d-PEIE) showed significantly improved luminance, efficiency, and lifetimes. These improvements are attributed to d-PEIE decreasing the work function of the Al metal cathode, as shown by ultraviolet photoelectron spectroscopy (UPS) analysis, and improving the gas and moisture resistance.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) and funded by the Ministry of Education (grant number 2015R1D1A1A01061340) and the Joint Program for Samsung Electronics-Yonsei University.
All Science Journal Classification (ASJC) codes
- Materials Chemistry