Phosphorescent organic light-emitting diodes using an iridium complex polymer as the solution-processible host material

Abstract

We prepared an iridium polymer complex having 2-phenylpyridine as a η2-cyclometallated ligand, a new OLED containing a solution-processible iridium polymer as a host, and a phosphorescent iridium complex, [Ir(piq-tBu)3] as a guest. This is the first example to apply a phosphorescent iridium complex polymer to a host material in a phosphorescent OLED. A phosphine copolymer ligand made from methyl methacrylate (MMA) and 4-styryldiphenylphosphine can be used as an anchor polymer, which coordinates to luminescent iridium units to form a host metallopolymer easily. The OLED containing the host iridium-complex polymer film, in which the guest, 2 wt % Ir(piq-tBu)3, was doped, showed red electroluminescence as a result of efficient energy transfer from the iridium polymer host to the iridium guest. The maximum current efficiency of the device was 1.00, suggesting that a soluble iridium complex polymer can be used as a solution-processible polymer host in EL devices. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4358–4365, 2009