Xie, G.G.XieFehse, KarstenKarstenFehseLeo, K.K.LeoGather, M.C.M.C.Gather2022-03-042022-03-042013https://publica.fraunhofer.de/handle/publica/23298710.1016/j.orgel.2013.05.0342-s2.0-848789989522-s2.0-84885476945An additional p-doping layer is added to the P-I-N stack of top-emitting organic light-emitting diodes (TEOLEDs) to control the electron tunneling current and improve interfacial stability. In addition, double p-doped layers, which are adjacent to the bottom-anode, are introduced to simultaneously optimize robustness and doping efficiency of p-type doping. In the emissive layer (EML), a second assistant emitter molecule is used which transfer its triplet energy to the actual emitter which is lower in energy, thus increasing the luminous efficacy. Such a co-doped dual-emitter layer is able to separate polarons and excitons and thus reduces chemical degradation. Compared to conventional P-I-N TEOLEDs, our novel P-I-N-P device shows negligible increase of driving voltage at low bias but offers significantly increased efficiencies. In addition, the P-I-N-P stack renders the electrical properties less sensitive to thickness variations and prolonged operation, which is attrib uted to the existence of a one-sided abrupt N-P tunneling junction beneath the top cathode contact.en621621journal article