Gallium complexes in three-layer organic electroluminescent devices

Organic light-emitting diodes fabricated by subsequently spin-coating two layers-a hole-transporting followed by a metal chelate emissive layer - onto poly(3,4-ethylene-dioxythiophene)/poly(styrenesulfonate) are presentedfor the first time. The electron-hole recombination occurs in a layer consisting of Ga complexes (see Figure), which exhibit high fluorescence quantum yields, and their emission spectra are blue-shifted relative to that of tris(8-hydroxyquinoline) aluminum. By doping this spin-coated emission layer with fluorescent emitters the emission band can be shifted within the visible spectral range.