Highly Efficient Red Emitting OLEDs Prepared from Nona-Coordinated Europium(III) Complexes

Rashid Ilmi, Xiaoyang Xai, José D.L. Dutra, Gabriel Silva Santos, Liang Zhou, Wai-Yeung Wong, Paul Raithby, Muhammad Khan

Research output: Contribution to journalArticlepeer-review

Abstract

We have designed and synthesized three nona-coordinated organoeuropium complexes (OEuCs) with the general formula [Eu(btfa) 3(FurTerPy)] (Eu1), [Eu(btfa) 3(ThioTerPy)] (Eu2), and [Eu(btfa) 3(NapTerPy)] (Eu3) by employing a primary 4,4,4-trifluoro-1-phenyl-1,3-butanedione (btfa) antenna ligand and three functionalized 2,2′:6′,2″-terpyridine (TerPy) ligands bearing different electron-donating groups at the 4′ position, namely, FurTerPy = 4′-(furan-2-yl)-2,2′:6′,2″-terpyridine; ThioTerPy = 4′-(thiophen-2-yl)-2,2′:6′,2″-terpyridine; and NapTerPy = 4′-(naphthalen-1-yl)-2,2′:6′,2″-terpyridine. The detailed photophysical properties of Eu1, Eu2, and Eu3 were analyzed using both experimental and computational methods. By analyzing the experimental and time-dependent density functional theory (TD-DFT) data in conjunction with the Lanthanide Luminescence Software Package (LUMPAC), we further elucidated the energy transfer processes in the OEuCs. Finally, the complexes were tested as the emitting layer (EML) in a multilayered device to fabricate red organic light-emitting diodes (R-OLED). Through optimization and device engineering, we have achieved a remarkable electroluminescence (EL) performance of maximum current efficiency (η c) = 12.32 cd/A, maximum power efficiency (η p) = 11.73 lm/W, and maximum external quantum efficiency (EQE max) = 10.20%, respectively, for the Eu3-based double-EML OLED. To the best of our knowledge, this is the highest reported overall EL performance among the OEuCs until now.

Original languageEnglish
JournalACS Applied Electronic Materials
Early online date2 Apr 2024
DOIs
Publication statusE-pub ahead of print - 2 Apr 2024

Data Availability Statement

The data that support the findings of this study are available in the Supporting Information of this article.

Keywords

  • 4,4,4-trifluoro-1-phenyl-1,3-butanedione
  • Förster energy transfer
  • carrier trapping
  • energy transfer mechanism
  • europium(III)
  • red electroluminescence
  • terpyridine

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Electrochemistry

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