Organic Interface Engineering for Stable Green PHOLEDs through an Ultrathin Interface Tunneling Layer. Issue 21 (24th September 2018)

• Record Type: Journal Article
• Authors: Park, So‐Ra; Ahn, Dong A; Seol, Ki‐Hyuk; Yang, Sena; Kim, Jeong Won; Lampande, Raju; Nam, Hyoungsik; Suh, Min Chul
• Is Part Of: Advanced materials interfaces. Volume 5:Issue 21(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-24
• Subjects: device lifetime -- highly efficient green PHOLEDs -- improved device stability -- interface modification -- interface tunneling layer; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201801034
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Device stability of the organic light emitting diodes is strongly affected by accumulated charge carriers at both interfaces of emitting layer (EML). To reduce the stress of devices from undesirable charge accumulation near EML, an interface tunneling layer (ITL) is introduced. Notably, ITL affects charge injection behavior, which helps to reduce a chemical degradation of EML. As a result, significantly improved device lifetime (by 2.5 times, ≈402.1 h, LT 75) after the introduction of pretty thin (1 nm) ITL between EML and electron transporting layer is obtained. Such a tunneling behavior by analysis of impedance spectroscopy (IS), ultraviolet photoelectron spectroscopy (UPS), and electric stress for electron and hole only devices are verified. Abstract : A new method to improve the device stability via interface modification is introduced. A 1 nm ultrathin interface tunneling layer both sides of emitting layer is utilized. With this approach, highly efficient green phosphorescent light emitting diodes with outstanding device stability can be realized.