Ultrathin Nanogenerators as Self‐Powered/Active Skin Sensors for Tracking Eye Ball Motion

Abstract

International audienceUltrathin piezoelectric nanogenerator (NG) with a total thickness of ≈16 μm is fabricated as an active or self-powered sensor for monitoring local deformation on a human skin. The NG was based on an anodic aluminum oxide (AAO) as an insulating layer grown on a thin Al foil by anodization, on which a thin film made of aligned ZnO nanowire compacted arrays is grown by solution chemistry. The performance of the NG is characterized with the assistance of the finite element method (FEM) simulation. The extremely thin NG is attached on the surface of an eyelid, and its output voltage/current characterizes the motion of the eye ball underneath. Since there is no external power needed for the operation of the NG, this self-powered or active sensor can be effective in monitoring sleeping behavior, brain activities, and spirit status of a person as well as any biological associated skin deformation

Unveiling the Influence of Surface Fermi Level Pinning on the Piezoelectric Response of Semiconducting Nanowires

“…Such dissymmetry had already been noticed in a previous study of self-powered/active flexible skin sensors. [23] 3. Simulation Framework…”

“…Noteworthy, when the composite was integrated on a flexible substrate and evaluated under bending, a dissymmetric performance was observed, depending on whether the device was bent upward or downward, confirming a previous observation. [23] Fully coupled simulations of this structure were performed using the finite element method (FEM) in order to calculate the potential generated by this structure. The influence of SFLP effect was studied.…”

“…Chief among them are (1) decent and length-dependent performance of ZnO NWs, [18] while anticipations based on analytical and computational study showed that the output of NWs under compression were reduced to a few millivolts and presenting length-independent performance due to the screening effect; [19,20] (2) enhanced piezoelectric coefficients, [21] which were measured for ZnO NWs with diameter beyond the size effects anticipated by ab initio method; [22] and (3) dissymmetric piezoelectric response of bent nanogenerators (NGs) under tensile and compressive strain. [23] Relatively high potentials (>0.2 V) can be repeatedly obtained from NGs integrating long and large ZnO NWs [24][25][26][27] with presumably nonintentional doping. Increasing the doping concentration will reduce the generated piezopotential.…”

Novel piezoelectric paper based on SbSI nanowires

“…The first piezoelectric nanogenerator (NG) based on zinc oxide nanowires for mechanical to electrical energy conversion was proposed by Wang and Song (2006). It started with promising investigations on such devices, for example, to harvest vibrations (Chen et al 2010(Chen et al , 2013Poulin-Vittrant et al 2015;Zhan et al 2014), human body motion (Lee et al 2014;Yang et al 2009), wind (Gao et al 2015), acoustic waves (Wang et al 2007), and other mechanical energy forms (Wang 2012). Piezoelectric generators are also used as passive or self-powered sensors (Chen et al 2013;Fan et al 2012;Fang et al 2015;Hua and Wang 2015).…”

Recent progress on piezoelectric energy harvesting: structures and materials

“…As the NWs can be utilized to fabricate a flexible, wearable, or implantable energy harvesting device because of high sensitivity to small, irregular mechanical disturbances [105,106], meanwhile, this material can also be combined with polymer to desire a feasible NG, which is potential material in the application of implantable self-powered device in the medical area. Wang et al [107] fabricated an active or self-powered sensor (total thickness ≈ 16 μm) to monitor sleeping behavior, brain activities, and spirit status of a person as well as any biologically associated skin deformation, as the high sensitivity of super-flexible nanowire ZnO NG enabled to measure a slight local deformation on one's eyelid caused by the motion of eye ball underneath, as shown in Fig. 35.…”