Thermally stable inverted organic light-emitting diodes using Ag-doped 4,7-diphenyl-1,10-phenanthroline as an electron injection layer

Chunliu Gong, Yachen Xu, Yuling Liu, Yingjie Liao, Weixia Lan, Bin Wei, Lian Duan, Wai Yeung Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

The thermal stability of organic functional materials affects the performance and lifetime of organic light-emitting diodes (OLEDs). We have developed a thermally stable inverted OLEDs (IOLEDs) by employing silver (Ag) doped into 4,7-diphenyl-1,10-phenanthroline (Bphen) as an n-type doped electron injection layer (EIL). We found that the formation of Ag complexes by coordination reaction could enhance the thermal stability and produce an asymmetric diffraction pattern based on an analysis of grazing incidence small angle X-ray scattering. Interestingly, with the annealing temperature increasing to 100 °C, the electrical properties of electron-only cells show differentiated phenomenon that the current density based on Ag dopant remains basically unchanged, which is opposite to Cs2CO3 dopant. In addition, at the high temperature of 100 °C, the IOLEDs with Cs2CO3 doped Bphen as an EIL was damaged completely, while the Ag dopant-based devices still maintained good photoelectrical characteristics. Finally, we have demonstrated that the optimized IOLEDs achieved a 40.3% enhancement in current efficiency compared to the conventional device. This work provides a new strategy to increase the thermal stability and performance for the application of IOLEDs operated under high temperature.

Original languageEnglish
Article number106307
JournalOrganic Electronics
Volume99
DOIs
Publication statusPublished - Dec 2021

Keywords

  • Annealing
  • Grazing incidence small angle X-ray scattering
  • Inverted organic light-emitting diodes
  • Silver-doped
  • Thermal stability

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Chemistry(all)
  • Biomaterials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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