Efficient greenish-blue thermally activated delayed fluorescence Zn complex for organic light emitting devices
Journal
Organic Electronics
Journal Volume
138
ISSN
1566-1199
Date Issued
2025-03
Author(s)
Chih-Pin Han
Chao-Hsien Hsu
Ching-Yuan Chu
Tzu-Hao Huang
Chih-Lun Yi
Jake A. Tan
Wen-Yi Hung
Abstract
A greenish-blue zinc complex Zn(PhOBz)-PXZ with enhanced thermally activated delayed fluorescence (TADF) properties has been prepared from Zn(OAc)2 and 4PXZ2OHBz, a 2-(1H-benzimidazol-2-yl)phenol-based TADF ligand. The TADF phenomenon has been confirmed by time-resolved photoluminescence (TrPL) studies. The DFT calculations show spatially well-separated HOMO and LUMO in their ground states, along with a small energy splitting between the excited singlet (S1) and triplet (T1) states, in a good agreement with the TADF mechanism. Due to the high thermal stability of Zn(PhOBz)-PXZ, OLED devices can be fabricated by vacuum vapor deposition, and greenish-blue OLEDs with the maximum emission at 521 nm were successfully demonstrated. The maximum external quantum efficiency (EQEmax) of 10.6 %, with Commission Internationale de l'Eclairage (CIE) coordinates of (0.28, 0.47) were recorded. Zinc TADF complexes have the advantages of cost-effectiveness, greater abundance of natural resources, environmentally friendly metals, making them potential replacements for future precious metal emitters.
Subjects
Complex
Organic light emitting diode (OLED)
Thermally activated delayed fluorescence (TADF)
Zinc
SDGs
Publisher
Elsevier BV
Type
journal article