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Keywords:

  • electrical doping;
  • P–I–N–P;
  • top-emitting;
  • tunnel junction

We report a P–I–N–P top-emitting organic light-emitting diode (TEOLED) that contains an additional p-doped hole transporting layer between the conventional n-doped electron transporting layer and the top cathode. The TEOLED comprises MoOx in different positions of the device stack (i) as a buffer layer and a p-dopant to improve the hole injection efficiency from the anode side and to form an abrupt tunnel junction at the cathode side and (ii) a capping layer to tailor the out-coupling efficiency. The N–P tunnel junction provides a simple approach for balancing charge injection and thus results in simultaneous improvements on current, power and external quantum efficiencies (maxima of 39, 35, and 45%, respectively).