Dual‐Function Deep‐Red Phosphorescent OLEDs for Fully Integrated Micro‐Displays and Compact Biomedical Sensing

ABSTRACT Modern wearable and portable systems require light sources compatible with high‐resolution micro‐display architectures and biomedical sensing. However, current organic light emitting diode (OLED) platforms struggle to satisfy combined demands of deep‐red emission, high efficiency, long operational lifetime, and seamless photodetector integration. Here we report BThiq‐CN , a new asymmetric Ir(III) phosphor featuring a benzo[b]thiophene‐isoquinoline ligand that delivers spectrally pure deep‐red emission (644/700 nm, CIE of (0.710, 0.290)) meeting BT.2020 requirements. OLEDs incorporating BThiq‐CN achieve external quantum efficiency of 16.89% and operational lifetime LT 90 of 1,961 h at 100 cd m − 2 . Leveraging this robustness and color purity, we fabricate a 64 × 64 pixels deep‐red micro‐OLED display on a commercial thin film transisitor (TFT) backplane, demonstrating pixel‐uniform, high‐contrast emission suitable for next‐generation near‐eye systems. Beyond displays, BThiq‐CN enables compact biomedical sensing by integrating the OLED with an organic photodetector to form a transmission‐mode photoplethysmography (PPG) module, yielding pulse waveforms surpassing those from commercial red emitters. Enhanced systolic/diastolic peak clarity and signal fidelity highlight the unique biomedical advantages of deep‐red OLED excitation. This work establishes BThiq‐CN as a benchmark deep‐red emitter with dual‐function capability for both high‐resolution micro‐display technology and biomedical sensing, advancing compact, reliable and multifunctional health‐monitoring systems.