npj Flexible Electronics (Mar 2023)

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

  • Ho Seung Lee,
  • Byeongju Noh,
  • Seong Uk Kong,
  • Yong Ha Hwang,
  • Ha-Eun Cho,
  • Yongmin Jeon,
  • Kyung Cheol Choi

DOI
https://doi.org/10.1038/s41528-023-00248-1
Journal volume & issue
Vol. 7, no. 1
pp. 1 – 12

Abstract

Read online

Abstract 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 SpO2 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 SpO2 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 SpO2 measurement accuracy as well as all-in-one clothing-type pulse oximetry with FQPO.