Principles of material selection for thin-film organic light-emitting diodes

Properties of materials for organic light-emitting diodes (OLEDs), such as high values of mobility of charge carriers and low values of barrier heights for injection of those carriers, depend on the positions of molecular orbitals. It is known that in aryl compounds these positions could be influenced by introduction of heteroatoms such as sulfur and nitrogen into the molecules and by introduction of donor and acceptor substituents. This correlation of composition-structure-physical properties was used by the authors earlier in screening of materials for nonlinear optics and could be used for screening materials for OLEDs with obvious modifications bound to optimization of intermolecular contacts, and to demand high quantum yield of luminescence, etc. These modifications were illustrated by discussion of the optimization methods for metal oxyquinolinates.