First Dual Red–Near-Infrared Emissive Solution-Processed Organic Light-Emitting Diode Based on Europium–Ytterbium Mixed-Ligand Complexes for Pulse Oximetry

For oximetry applications, the first dual red–near-infrared (NIR) emissive organic light-emitting diode (OLED) based on mixed-ligand complexes EuxYb1–x(dbm)3BPhen (x = 0; 0.01; 0.02; 0.05; 0.1; 1) is obtained. The photoluminescence quantum yields of the ytterbium and europium in the obtained complexes reach 0.9 and 31%, respectively, which are rather high values for the complexes of these ions. Dual visible–NIR emissive compounds EuxYb1–x(dbm)3BPhen are tested in OLEDs, and Eu0.05Yb0.95(dbm)3BPhen demonstrates the most intense electroluminescence both in visible (270 cd/m2) and NIR range (19 μW/cm2). The Eu0.05Yb0.95(dbm)3BPhen-based OLED is successfully used to produce the first lanthanide OLED-based pulsimeter prototype.