Issue 31, 2014

Os(ii) metal phosphors bearing tridentate 2,6-di(pyrazol-3-yl)pyridine chelate: synthetic design, characterization and application in OLED fabrication

Abstract

Treatment of 2,6-di(5-trifluoromethylpyrazol-3-yl)pyridine (pz2py)H2 with Os3(CO)12 affords a mononuclear Os(II) complex [Os(pz2py)(CO)2(H2O)] (1) in excellent yield. Ligand substitution reactions were next executed to identify products with good photoluminescence at both fluid and solid states at RT. Therefore, substitutions with phosphorus donors such as PPh2Me and 2,6-bis(diphenylphosphinomethyl) pyridine (P2N), and nitrogen donors such as pyridine, 2,2′-bipyridine (bpy) and 2,2′:6′,2′′-terpyridine (tpy), afforded products with formula [Os(pz2py)(PPh2Me)2(CO)] (2), [Os(pz2py)(P2N)] (3), [Os(pz2py)(CO)2(py)] (4), [Os(pz2py)(CO)(bpy)] (5) and [Os(pz2py)(CO)(tpy)] (6). The single crystal X-ray structural analyses were executed on 1, 2, 3 and 6 to reveal the bonding of pz2py chelate as well as the structural effect imposed by the phosphorus and/or nitrogen donor groups. The photophysical properties were studied and discussed using the results of DFT and TDDFT calculations. For application, fabrication and analysis of organic light emitting diodes (OLEDs) were also carried out. OLEDs using 2 as a dopant exhibited an intense yellow emission with a maximum efficiency of 18.3%, 61.0 cd A−1, and 53.8 lm W−1, which are higher than those of most reported devices with greenish yellow/yellow emitters. Moreover, dopant 2 was combined with a red emitting dopant Os(bpftz)2(PPhMe2)2 (7) and two different sky-blue phosphors FIrpic and Ir(bptz)2(bdp) (8) to fabricate white OLEDs (WOLEDs). Device W1 achieved the highest efficiency of 18.0%, 33.9 cd A−1, and 31.2 lm W−1 while the maximized efficiency of device W2 was 15.3%, 29.3 cd A−1, and 27.0 lm W−1. Both devices showed stable warm-white emissions with a wide luminance range. In addition, device W2 exhibited a higher CRI of 84.2 with a low CCT of 2675 K at 103 cd m−2, making it a potential candidate for domestic lighting.

Graphical abstract: Os(ii) metal phosphors bearing tridentate 2,6-di(pyrazol-3-yl)pyridine chelate: synthetic design, characterization and application in OLED fabrication

Supplementary files

Article information

Article type
Paper
Submitted
29 ኤፕሪ 2014
Accepted
06 ጁን 2014
First published
09 ጁን 2014

J. Mater. Chem. C, 2014,2, 6269-6282

Os(II) metal phosphors bearing tridentate 2,6-di(pyrazol-3-yl)pyridine chelate: synthetic design, characterization and application in OLED fabrication

J. Liao, Y. Chi, Y. Su, H. Huang, C. Chang, S. Liu, G. Lee and P. Chou, J. Mater. Chem. C, 2014, 2, 6269 DOI: 10.1039/C4TC00865K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements