Synthesis, structural characterization, and electrophosphorescent properties of rhenium(I) complexes containing carrier-transporting groups

Document Type

Article

Publication Date

7-23-2007

Abstract

Two novel diimine rhenium(I) carbonyl complexes with the formula [Re(CO)3(L)Br], where L = 1-(4-5′-phenyl-1,3,4- oxadiazolylbenzyl)-2-pyridinylbenzoimidazole (1) and 1-(4-carbazolylbutyl)-2- pyridinylbenzoimidazole (2), have been successfully synthesized and characterized by elemental analysis, 1H NMR, and IR spectra. Their electrochemical, photophysical, and electroluminescent behaviors, along with the X-ray crystal structure analysis of 2, are also described. White electrophosphorescent devices were fabricated using 1 and 2 as emitters. The devices based on carbazole-containing (hole-transporting group) 2 with the structure ITO/m-MTDATA (30 nm)/NPB (20 nm)/2:CBP (8%, 30 nm)/Bphen (20 nm)/Alq3 (20 nm)/LiF (0.8 nm)/Al (200 nm) exhibit Commission Internationale de L'Eclairage coordinates of x = 0.34, y = 0.33 with a maximum brightness of 2300 cd/m2 at 580 mA/cm2. When a brightness of 1500 cd/m2 appears at 230 mA/cm2, the devices based on 10 wt % 2 still possess 56% of the maximum efficiency which appeared at 2.7 mA/cm2. These performances are among the best reported for devices using Re(I) complexes as emitters. By comparison of the electroluminescent properties of the devices based on 1 and 2, we conclude that the introduction of the carbazole group into the ligand improves the performance of 1-doped devices. © 2007 American Chemical Society.

Publication Source (Journal or Book title)

Inorganic Chemistry

First Page

6155

Last Page

6163

This document is currently not available here.

Share

COinS