Blue-emitting OLED with a broad spectral profile for phototherapy light source of neonatal jaundice

Neonatal jaundice, caused by bilirubin accumulation due to liver immaturity, requires blue light phototherapy for effective treatment. Conventional LED-based systems are limited by their narrow spectral width, potential thermal hazards, and the requirement to separate infants from caregivers. By integrating pure-blue fluorescent (BCzVBi) and sky-blue phosphorescent (FIrpic) emitters into a tandem organic light-emitting diode (OLED) structure, we developed blue OLEDs with a broad emission spectrum (430–530 nm) that better aligns with the bilirubin absorption band. The devices achieve a sufficient spectral power density (10–30 μW/cm²/nm) while maintaining surface temperatures well below 42 °C, making them well-suited for wearable applications. Emission profiles and doping concentrations were optimized to broaden the EL spectra. Thermal tests confirmed stable and safe operation under driving voltages of 13–14 V. The developed tandem OLEDs, featuring both a broad spectrum and high efficiency, represent a promising alternative to conventional LEDs for safer and more effective phototherapy of neonatal jaundice.