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.

Multi-directionally wrinkle-able textile OLEDs for clothing-type displays

A clothing-type wearable display can be utilized in fashion,bio-healthcare,and safety industries as well as smart textiles for the internet of things(IoTs)and wearable devices.In response to this trend,we demonstrate a textile display that can endure the active movements of a human body.It can be applied to any kind of textile,and is durable against conditions such as rain,sweat,and washing.As a key technology for realizing the multi-directional wrinkle-able textile display,we fabricated a stress-lowering textile platform with an ultrathin planarization layer replicated from the flat surface of glass.An elastomeric strain buffer for reducing mechanical stress is also inserted into the textile platform.Here,organic light-emitting diodes(OLEDs)with red,green and blue color,thin film transistors(TFTs)fabricated at a low temperature below 150℃,and a washable encapsulation layer blocking both gas and liquid were demonstrated on the textile platform.