New charge carriers and platinum-based phosphors for organic light emitting devices.

摘要

Organic light emitting devices 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 first chapter describes how these devices work and how the materials affect device properties.; The second chapter describes new charge carriers based on indolo carbazoles. The synthesis and characterization of these materials are described. The optical and electrochemical properties are compared to calculated values from density functional theory. These materials were used as hole transport materials in a standard device and host materials for singlet and triplet dopants.; The third chapter describes the synthesis and characterization of a series of square planar platinum phosphors based on a single cyclometalating ligand, such as 2-phenylpyridine, and an ancillary diketonate ligand, such as acetyl acetonate. These materials emit efficiently from mixed metal-to-ligand charge transfer and triplet ligand centered states with lifetimes on the order of microseconds. It is shown that the energy of emission can be tuned by using electron donating and withdrawing substituents on the phenylpyridine ligand.; These platinum phosphors can emit from low energy aggregate states due to interactions with the exposed ligand and metal orbitals. Chapter 4 describes how excimer formation occurs in solution and how intermolecular overlap affects these states. A series of crystal structures are presented for nonfluorinated and difluormated derivatives. These crystal structures are correlated to the emission of the crystals and an example of a ligand excimer and metal-metal dimer is described. In addition, one of these materials has been doped into various host materials and was found to emit simultaneously from high energy monomer and low energy aggregate states. This principle has been used to fabricate an efficient single dopant white light emitting device.