Effect of injection layer sub-bandgap states on electron injection in organic light-emitting diodes

• Verfasst von: Hinzmann, Carsten [VerfasserIn]
• Verfasst von: Hofstetter, Yvonne J. [VerfasserIn]
• Verfasst von: Hopkinson, Paul E. [VerfasserIn]
• Verfasst von: Vaynzof, Yana [VerfasserIn]
• Titel: Effect of injection layer sub-bandgap states on electron injection in organic light-emitting diodes
• Verf.angabe: Carsten Hinzmann, Osnat Magen, Yvonne J. Hofstetter, Paul E. Hopkinson, Nir Tessler, and Yana Vaynzof
• E-Jahr: 2017
• Jahr: January 18, 2017
• Umfang: 8 S.
• Fussnoten: Gesehen am 10.07.2018
• Titel Quelle: Enthalten in: American Chemical SocietyACS applied materials & interfaces
• Ort Quelle: Washington, DC : Soc., 2009
• Jahr Quelle: 2017
• Band/Heft Quelle: 9(2017), 7, Seite 6220-6227
• ISSN Quelle: 1944-8252
• DOI: doi:10.1021/acsami.6b14594
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1577444663

Abstract

It is generally considered that the injection of charges into an active layer of an organic light-emitting diode (OLED) is solely determined by the energetic injection barrier formed at the device interfaces. Here, we demonstrate that the density of surface states of the electron-injecting ZnO layer has a profound effect on both the charge injection and the overall performance of the OLED device. Introducing a dopant into ZnO reduces both the energy depth and density of surface states without altering the position of the energy levels - thus, the magnitude of the injection barrier formed at the organic/ZnO interface remains unchanged. Changes observed in the density of surface states result in an improved electron injection and enhanced luminescence of the device. We implemented a numerical simulation, modeling the effects of energetics and the density of surface states on the electron injection, demonstrating that both contributions should be considered when choosing the appropriate injection layer.