Flexible Wearable Strain Sensors Based on Laser-Induced Graphene for Monitoring Human Physiological Signals

Abstract

Flexible wearable strain sensors based on laser-induced graphene (LIG) have attracted significant interest due to their simple preparation process, three-dimensional porous structure, excellent electromechanical characteristics, and remarkable mechanical robustness. In this study, we demonstrated that LIG with various defects could be prepared on the surface of polyimide (PI) film, patterned in a single step by adjusting the scanning speed while maintaining a constant laser power of 12.4 W, and subjected to two repeated scans under ambient air conditions. The results indicated that LIG produced at a scanning speed of 70 mm/s exhibited an obvious stacked honeycomb micropore structure, and the flexible strain sensor fabricated with this material demonstrated stable resistance. The sensor exhibited high sensitivity within a low strain range of 0.4–8.0%, with the gauge factor (GF) reaching 107.8. The sensor demonstrated excellent stability and repeatable response at a strain of 2% after approximately 1000 repetitions. The flexible wearable LIG-based sensor with a serpentine bending structure could be used to detect various physiological signals, including pulse, finger bending, back of the hand relaxation and gripping, blinking eyes, smiling, drinking water, and speaking. The results of this study may serve as a reference for future applications in health monitoring, medical rehabilitation, and human–computer interactions.

Dual-band MIMO antenna with low mutual coupling for 2.4/5.8 GHz communication and wearable technologies

“…A compact, simple, and low-profile antenna is required for current and upcoming 5G and 6G communication systems, along with high antenna gain, wideband, low mutual coupling, and other basic and advanced parameters of the antenna [ 3 – 5 ]. Moreover, the increased demand for wearables also makes it critically important that antennas work properly around the human body [ 6 ]. A compact and simplified geometry antenna operating over the industrial, scientific and medical (ISM) and wireless local area networks (WLAN) bands has remained a top research topic during the past decade.…”

Recent Advances in Graphene-Enabled Materials for Photovoltaic Applications: A Comprehensive Review

“…However, due to poor optical transparency, such materials are not viable candidates for the electrode of organic PV cells. 93,94 However, due to the great properties of GA, it can be preferred for the electrodes of organic solar cells (OSCs). 95,96 The comparative performance study of different materials used for OSC electrodes with and without GA shows that GAbased electrode performance easily exceeds that of ITO.…”

“…Thus, metal grids, organic compounds, carbon nanotubes, and metal oxides are used as electrode ITO alternatives. However, due to poor optical transparency, such materials are not viable candidates for the electrode of organic PV cells. , However, due to the great properties of GA, it can be preferred for the electrodes of organic solar cells (OSCs). , …”

“…Fluorine-doped tin oxide is also a candidate similar to ITO for electrodes. However, the major challenge with ITO is its cost as it is a rare earth metal, it is sensitive to higher and lower pH values, and it has brittleness, manufacturing issues, etc . The solar cell industry requires flexible (avoiding brittle ITO layers), durable, conductive, thermally stable materials with high optical transparency to substitute ITO.…”

Exploring the weak visible-near-infrared and NO2 detection capabilities of PbS/Sb2O5 heterostructures with DFT interpretations

“…Researchers are becoming increasingly interested in low-power, small-scale germanium photodetectors that can be integrated with silicon transistor technology as a crucial part of optical interconnection, as predicted by Moore's law in photonics. Image sensing, optical communication, and nighttime surveillance are just a few of the many potential uses for broadband photodetectors [8]. To create high-performance infrared photodetectors, many different materials were investigated.…”