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-ethylenedioxythiophene)/poly(styrenesulfonate) are presented for 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.