Voltage color tunable OLED with (Sm,Eu)-β-diketonate complex blend

Light emission from organic electroluminescent diodes (OLEDs) in which mixed samarium and europium β-diketonate complexes, [Sm0.7Eu0.3(TTA)3(TPPO)2], was used as the emitting layer is described. The electroluminescence spectra exhibit narrow peaks arising from 4f-intraconfigurational transitions of the Sm3+ and Eu3+ ions and a broad emission band attributed to the electrophosphorescence of the TTA ligand. The intensity ratio of the peaks determined by the bias voltage applied to the OLED, together with the ligand electrophosphorescence, allows to obtain a voltage-tunable color light source.