Flexible and Transparent Electronic Skin Sensor with Sensing Capabilities for Pressure, Temperature, and Humidity

Abstract

Inspired by the interlocked biological geometry of human skin, herein, we design a flexible and transparent sensor with interlocked square column arrays with composites of Ag nanoparticles (AgNPs), citric acid (CA), and poly(vinyl alcohol) (PVA), which exhibit multisensory capabilities for pressure, temperature, and humidity. As a flexible pressure sensor, the interlocked AgNPs/CA/PVA sensor possesses a high sensitivity (−1.82 kPa–1), low detection limit (10 Pa), fast response (75 ms), and outstanding stability due to the high sensitivity of the contact resistance of the interlocked square column arrays to pressure. Because of the rigid dependence of the resistance of the AgNPs/CA/PVA composite on temperature, the interlocked AgNPs/CA/PVA sensor can also act as a temperature sensor, which exhibits high resolution (0.1 °C) and reliability in detecting ambient temperature. In addition, it is found that the amount of water molecules adsorbed by PVA and CA changes with the ambient humidity. Therefore, the interlocked AgNPs/CA/PVA sensor is also able to detect humidity in real time. This work proposes a simple but useful route to fabricate a flexible and transparent electrical skin sensor, which has great potential in the perception of pressure, temperature, and humidity.

Electrically Conductive AgNPs/TPU-Electrospun Fibers with Hierarchical Microstructures by a One-Step Method for a High-Performance Flexible Pressure Sensor

“…As shown in Figure 5h, when a finger was rapidly pressed on and off the sensor, the response and recovery times were 100 and 70 ms, respectively, which are closer to the response time of human skin (30−50 ms), indicating a low hysteresis. 56 A comparison of the sensitivity and sensing range of the sensors reported in the previous work 13,15,22,26,34,36,39,[41][42][43]54 is given in Figure 5i, where it is found that the AgNPs/TPU pressure sensor had a relatively higher sensitivity and wider detection range. For a clearer comparison, the sensitivity and detection range of various microstructured sensors are given in Table S2.…”

“…The microstructures in these sensors can usually be fabricated by specific methods such as laser-scribing, bionic replica, template transfer, , and screen printing . Combined with other related research reports, it can be seen that these microstructure preparation processes can lead to improvements in sensor sensitivity and detection range .…”

Flexible thermoelectric CMTs/KCl/gelatin composite for a wearable pressure and temperature sensor

“…5 For example, exible electronic sensors can convert physiological activity signals into visible electrical signals through signal conduction, which has great application prospects in the elds of human clinical diagnosis, humancomputer interaction, 6 articial intelligence robotics, 7 and exible electronic skin. [8][9][10] In particular, exible sensors can be used for multifunctional sensing, such as pressure and temperature sensing, [11][12][13][14][15] through the thermoelectric, piezoelectric, and friction electric properties of the materials. Ionic gels with dual stimulated temperature and pressure responsive materials are expected to provide an idea for the construction of temperature and pressure sensors.…”

Transferable microfiber laser arrays for high-sensitivity thermal sensing

“…11,12 However, conventional commercial electronic temperature sensors require heavy energy supply systems and are vulnerable to electromagnetic interference. 13 Compared to the electronic counterpart, optic-based temperature sensors exhibit the advantages of being non-contact and having higher sensitivity and low detection limits. 14 With the merits of having small mode volumes, high quality (Q) factors and high integration capability, 15 whisper-ing-gallery-mode (WGM) microresonators are excellent platforms in the fields of nonlinear optics, 16 low threshold lasing, 17 on-chip optical communication 18 and miniature sensing.…”

“…11,12 However, conventional commercial electronic temperature sensors require heavy energy supply systems and are vulnerable to electromagnetic interference. 13 Compared to the electronic counterpart, optic-based temperature sensors exhibit the advantages of being non-contact and having higher sensitivity and low detection limits. 14…”