Performance-enhanced and cost-effective triboelectric nanogenerator based on stretchable electrode for wearable SpO2 monitoring

Recently, stretchable and wearable health monitoring equipment has greatly improved human’s daily life, which sets higher demands for portable power source in stretchability, sustainability, and biocompatibility. In this work, we proposed a stretchable triboelectric nanogenerator (TENG) based on stretchable poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/porous carbon hybrid for oxyhemoglobin saturation (SpO2) monitoring. To combine advantages of carbon material for its high conductivity and organic electrode for its high stretchability, we spin-coated a solution of PEDOT:PSS/porous carbon onto a plasma-treated pre-stretched Ecoflex film to fabricate a stretchable electrode with rough surface. Due to its roughness and high potential difference with the dielectric material, the stretchable-electrode-based TENG exhibited better performance compared to the pristine TENG based on carbon or PEDOT:PSS material. The output voltage and current reached up to 51.5 V and 13.2 µA as the carbon concentration increased. More importantly, the performance further increased under large strain (100%) which is suitable for wearable systems. Finally, the device demonstrated its application potential for powering a flexible blood oxygen monitor. This simple and cost-effective method can enhance the stretchability and stability of organic/inorganic electrode-based TENG, which paves the development of high-performance stretchable TENG.