Ultrahigh Sensitivity Flexible Pressure Sensors Based on 3D‐Printed Hollow Microstructures for Electronic Skins

Abstract

Here, ultrahigh sensitivity flexible pressure sensors comprised of 3D‐printing flexible hollow microstructure substrates, gold film spray‐coated on the substrates, and Ag interdigital electrodes are reported. The finite element analysis (FEA) shows that the hollow microcylinder structure has better compression performance compared to solid microcylinder structure. Diverse solid and hollow microstructures, such as microcylinder, microsawtooth, and microrectangle structures are built to investigate the performance difference. The sensitivity of the sensor with hollow microcylinder structure is nearly 100% higher than that of the solid microcylinder structure sensor. By comparing the sensors with different spray‐coating time of Au nanoparticles, the influence of electrode microcrack on sensitivity is revealed. The flexible hollow microcylinder structure sensor with electrode microcrack effect shows ultrahigh sensitivity of 419.622 kPa−1 in the ultralow pressure range (< 100 Pa), rapid response time (30.76 ms), and recovery time (15.17 ms). To show the great performance of the sensor, it is used to detect human physiological signals such as cheek bulging, throat swallowing, and artery pulse. To realize the spatial sensing resolution, a 3 × 4 pressure sensor array is fabricated. The applications of the sensor may pave the way in human physiological signals monitoring and electronic skins in the future.

Morphological Engineering of Sensing Materials for Flexible Pressure Sensors and Artificial Intelligence Applications

“…The one-pot multimaterial 3D printing process enables the integration of various functional inks into the 3D sensor and provides a conformal design and high performance. For the 3D printing method, non-conductive polymer material is usually used for backbone structuring, and successive post processing is needed to add the conductive layer for their application in electronic devices [ 260 ]. Xia et al reported a flexible piezoresistive sensor based on 3D-printing and spray-coating [ 260 ].…”

“…For the 3D printing method, non-conductive polymer material is usually used for backbone structuring, and successive post processing is needed to add the conductive layer for their application in electronic devices [ 260 ]. Xia et al reported a flexible piezoresistive sensor based on 3D-printing and spray-coating [ 260 ]. A hollow microcylinder structure flexible substrates is firstly fabricated by 3D-printing using photosensitive resin, and then, Au nanoparticles were spray-coated on the microstructured substrates to form the sensing layer.…”

All‐3D‐Printed, Flexible, and Hybrid Wearable Bioelectronic Tactile Sensors Using Biocompatible Nanocomposites for Health Monitoring

“…Similarly, Xia et al reported 3D printed microstructures with gold nanoparticles for the flexible pressure sensors, for electronic skins. [39] In their work, by taking the advantage of an expensive stereolithography printer, they employed a bottomup fabrication process, and a microcylinder structure of flexible substrate was fabricated. Yet, not enough effort was spared in the combination of the structured layer formation and device fabrication to enable rapid, consistent, and cost-effective fabrication of sensitive, reliable, stable, and cost-effective wearable and flexible bioelectronic wearable sensors.…”

Ultrahigh Sensitive Flexible Piezoresistive Sensor with Carbonized Metal–Organic Framework Fe3O4@MIL-100(Fe)

“…where ΔR and ΔP are the relative resistance change and the pressure change respectively, and R 0 represents the initial resistance. 16 3. RESULTS AND DISCUSSION 3.1.…”