A Dual‐Emissive Lanthanide Organic light‐emitting diode for Single‐Pixel Pulse Oximetry: From Molecular Design to Device‐Level Integration

Organic light-emitting diodes (OLEDs) with dual emission in the red and near-infrared regions offer a breakthrough opportunity for simplifying pulse oximetry technology. Here, a new class of bimetallic complexes Eu_0.1Yb_0.9(L)₃Q (L = β-diketonates; Q = neutral ligands) with simultaneous emission at 612 and 978 nm has been reported, optimized for solution-processed OLEDs. A device based on Eu_0.1Yb_0.9(dbm)₃thiadiazolophenanthroline (TDZP) exhibits the highest electroluminescence intensity in both spectral ranges and is employed as a single-pixel light source in a custom-built pulse oximeter prototype. The prototype demonstrates real-time measurement of heart rate and blood oxygen saturation in full agreement with commercial devices. This is the first demonstration of a fully functional OLED-based oximeter relying on dual-emissive lanthanide complexes. This results pave the way for next-generation wearable biomedical sensors using advanced emissive materials and simplified device architectures.