A Highly Sensitive Bending Sensor Based on Controlled Crack Formation Integrated with an Energy Harvesting Pyramid Layer

Abstract

A highly sensitive bending sensor composed of patterned Pt lines, integrated with energy harvesting capability, is reported. The sensitivity of the bending sensor increases as the width of the Pt lines decreases, owing to the increase in crack density with decreasing line width. Furthermore, sensitivity increases with increasing bending cycles, but saturates at around 1000 cycles. Such a behavior corresponds to the increase and eventual saturation of crack density with increasing bending cycles. A microstructured polydimethylsiloxane layer is placed on top of the Pt lines to serve as a triboelectric energy harvesting layer, where human skin and the Pt lines are utilized as electrodes. Voltage and current of 18.6 V and 209 nA are generated, respectively, from gentle finger tapping. These demonstrations make the device highly useful for a wide variety of portable and wearable flexible electronic applications.

Flexible Sensory Systems: Structural Approaches

“…Owing to the vast range of uses of flexible electronic devices, flexibility requirements are very diverse; flexible devices must be capable of undergoing deformation, and simultaneously, functional properties and electronic performance parameters must be unaffected by the straining process. For example, the electrical resistance of a flexible electrode should be kept at a constant low value from low to high deformation [ 19 , 20 , 21 ]. Similarly, in the case of flexible solar cells and piezoelectric devices, they should exhibit high efficiencies within acceptable deformation [ 22 , 23 , 24 , 25 , 26 ].…”

Electrochemically Controlled Reversible Formation of Organized Channel Arrays in Nanoscale-Thick RuO2 Films: Implications for Mechanically Stable Thin Films and Microfluidic Devices

“…Furthermore, the size of the channels is found to be modulated by the state of lithiation (i.e., applied potential) and can be reversibly switched between fully closed and open states during electrochemical cycling. This approach demonstrates a path for electrochemical control of channel arrays for microfluidic, sensing, , or other applications. A finite element simulation was developed to explain the observed dependencies of this phenomenology on various parameters such as the film thicknesses and pattern periods (the period is defined as the distance between centers of adjacent notches).…”

Fully Elastomeric Fingerprint-Shaped Electronic Skin Based on Tunable Patterned Graphene/Silver Nanocomposites

“…Two-dimensional (2D) architectures, including meandering, 5 spiral, 35 and serpentine 36 patterns, have been employed to maintain high conductivity of electrodes under stretching. On the contrary, three-dimensional (3D) architectures, such as microdomes, 37 micropyramids, 38 micropillars, 39 and nanorods, 40 have been utilized to enhance the sensitivity. Many studies have focused on the improvement of the sensitivity, however, with partial compromise to the sensing range.…”