Enhanced sensitivity of multifunctional wearable sensor based on Mxene-Ag QDs organo-hydrogel for human-machine interface

Abstract

Recently, flexible, stretchable, and wearable sensors have received breakthrough due to wide applications in next generation portable electronics. Despite the use of many nanostructured hydrogels to construct stretchable devices, the integrated excellent optical and mechanical properties as well as intended functionality and satisfactory sensing performance are difficult to achieve with flexible/stretchable devices. Herein, we developed a multifunctional poly dopamine-titanium dioxide/silver quantum dots@ MXene organo-hydrogel (PDA-TiO2/AgQDs@MXene organo-hydrogel) as an optoelectronic wearable strain sensor with superior mechanical properties. The results reveal a promising sensor capability of monitoring and tracking human activities, vital signs, sign language, vocal cords vibrations during vocalization, touch, temperature, and photodetection of visible light. The developed sensor demonstrated superior anti-freezing point of − 45 °C, results in high performance capability at sub-zero temperatures. Additionally, it exhibited self-healing after 5 min with a healing efficiency (HE) 57% and an electrical healing efficiency (EHE) 70%. The water retention behavior (maintain 94.12% of the initial weight after 102 days) and excellent mechanical properties (570 kPa at strain 455%) were introduced. The sensor exhibited ultra-sensitivity (810%) during stretching to 400%, response time (19 ms), and also operated in other harsh circumstances such as bending, twisting, and compression with high reliability. The results provide a new path for future applications of the developed sensor in smart wearable electronics, soft robotics, artificial throat, optoelectronics, and smart healthcare monitoring and diagnosis.