Dopants for organic light-emitting devices

Organic light-emitting devices (OLEDs) with two-component layers consisting of a guest material (dopant) dispersed in a matrix (host) are examined in this work. Both emissive organic materials as dopants and non-emissive conductivity dopants are discussed. For the conductivity doping, lithium-coordinating agents including cryptands and crown ether derivatives have been used as dopants for electron-transport layers to improve the device operating voltages and luminance. Devices with oxidatively doped hole-transport layers consisting of novel hole-transporting ferrocene derivatives are also described. For the emissive doping, the spectral line shape dependence on the varied host materials for the emission of phosphorescent iridium complexes is examined. It has been shown that the value of Huang-Rhys parameters for the phosphorescence spectra decreases several times when non-polar ultra-high-band-gap hosts (UGHs) are used, compared to conventional carbazole-based host materials. Finally, a new class of efficient blue fluorescent dopants specifically designed as blue components for the white OLEDs with separate channels of harvesting blue singlet and red and green triplet excitons has been characterized.