Fig. 1: Characteristics of OLEDs with different EIL/ETL combinations.
From: Unravelling the electron injection/transport mechanism in organic light-emitting diodes
a Multilayer structure of an OLED, chemical structure of the materials used in the ETL and EIL, and schematic illustrations of their combination. b Luminance–voltage characteristics of green phosphorescent OLEDs prepared using various EIL/ETL combinations. c–g Summary of the energy diagrams around each cathode estimated from UPS and LEIPS, where EF and Evac represent the Fermi and vacuum levels, respectively. h, i Schematic illustrations of nitrogen-induced interactions around the cathode such as the coordination reaction with diffused Al atoms and the formation of H-bonds between Py-hpp2 and the material used in the ETL.
