Fiber-based quantum-dot pulse oximetry for wearable health monitoring with high wavelength selectivity and photoplethysmogram sensitivity

Increasing demand for real-time healthcare monitoring is leading to advances in thin and flexible optoelectronic device-based wearable pulse oximetry.Most previous studies have used OLEDs for this purpose,but did not consider the side effects of broad full-width half-maximum(FWHM)characteristics and single substrates.In this study,we performed SpO_(2)measurement using a fiber-based quantum-dot pulse oximetry(FQPO)system capable of mass production with a transferable encapsulation technique,and a narrow FWHM of about 30 nm.Based on analyses we determined that uniform angular narrow FWHM-based light sources are important for accurate SpO_(2)measurements through multi-layer structures and human skin tissues.The FQPO was shown to have improved photoplethysmogram(PPG)signal sensitivity with no waveguide-mode noise signal,as is typically generated when using a single substrate(30–50%).We successfully demonstrate improved SpO_(2)measurement accuracy as well as all-in-one clothing-type pulse oximetry with FQPO.