Fig. 4From: Efficient Trilayer Phosphorescent Organic Light-Emitting Devices Without Electrode Modification Layer and Its Working Mechanisma Schematic energy-level diagrams of the three devices. Simulated internal quantum efficiency (IQE) (solid green or red line) and external quantum efficiency (EQE) (scattered point) act as a function of the current density. Triplet and polaron densities (red and black lines) are calculated according to Eqs. (4)–(7). Hatched areas indicate the relative contribution of TPA and TTA as well as of the emission to the overall exciton decay. b–d correspond to device 1, device 2, and device 3, respectivelyBack to article page