Synthesis and characterization of cyclometalated iridium (III) complexes and their use in organic electroluminescent devices

Organic light emitting diodes (OLEDs) are a new type of display technology based on organic thin films. The materials that comprise these films are the subject of intense investigation, and must be able to meet certain criteria in order to be considered for these devices. The work presented here describes the development of novel molecular materials and their application in electroluminescent devices. And through the investigation, we realize our research goal to understand the underlying chemical and photophysical properties of the materials and know how the molecular properties affect the bulk properties of the materials. The first chapter describes the type of properties of the materials used, how they are used in devices, how these devices work, how the materials affect device properties and how materials properties affected by molecular structure.; The second chapter describes synthesis and photophysical studies of a series of facial and meridional iridium tris-cyclometalates. It is demonstrated in the preparative methods discuss that the reaction temperature can impart a significant control in the product configuration. For all of the cyclometalating ligands studied, there is a preference to form the facial isomers at high temperatures (>200°C) and the meridional isomers at lower temperatures (<150°C).; The third chapter describes an approach to making red, green and blue phosphors. A series of facial and meridional heteroleptic iridium tris-cyclometalates consisting of two pyrazolyl-based cyclometalatting ligands and a single luminophoric ligand are synthesized and their photophysical properties studied. It is shown that by simple substitution or modification of the pyrazolyl or pyridyl-based ligands, the ground and excited properties of the iridium complexes can be tuned.; In chapter 4 of this thesis, a series of cationic phenypyrazole-based Ir diimine complexes have been synthesized and their electrochemical, spectroscopic and electroluminescent properties examined. By simple modification of either the pyrazolyl or diimine ligands, the electrochemical gap and the energy of the lowest emissive state can be varied over a wide range.; We report in Chapter 5 of this thesis the synthesis and characterization of a series of dipyrrin-based biscyclometalated Ir(III) complexes. These complexes were made using a modified method of making metal dipyrromethene complexes. (Abstract shortened by UMI.)...