Organic/Inorganic Hybrid Stretchable Piezoelectric Nanogenerators for Self‐Powered Wearable Electronics

Abstract

Piezoelectric nanocomposites based nanogenerators (NGs) are gaining extensive attention as energy harvesters and self-powered tactile sensors for their applications in wearable electronics and personal healthcare. Herein, we report a facile, cost-effective and industrially scalable process flow for the fabrication of high performance mechanically robust nanocomposites based stretchable nanogenerator (SNG) on polydimethylsiloxane substrate. The inorganic / organic nanocomposite piezoelectric energy harvesting devices are realized by encapsulating the ZnO nanowires in a parylene C polymer matrix. The suggested fabrication process flow is implemented to fabricate SNG on flexible bank cards. The SNG devices exhibits excellent performances with a high open circuit voltage ~10 V, short-circuit current density ~0.11 µA/cm², and peak power ~3 µW under a vertical compressive force using a mechanical shaker. The obtained electricity from the SNG devices is used to drive electronic devices such as liquid crystal displays without employing any storage unit, implying the device significance in the field of consumer electronics. Besides, commercially available energy harvesting modules is used to store the generated electrical energy in capacitors. Furthermore, the SNG device can be adopted as self-powered wearable tactile sensor for detecting slight body movements which shows its potential applications in autonomous wearable electronics.

Deposition Time and Annealing Effects of ZnO Seed Layer on Enhancing Vertical Alignment of Piezoelectric ZnO Nanowires

“…As shown in Figure 6b, the average roughness of the annealed 100, 50, 10, and 5 nm seed layers was 2.86, 2.07, 1.66, and 1.58 nm, respectively, exhibiting a similar trend to the non-annealed seed layers (Table 4). The improvement of morphology, alignment, and verticality of the ZnO NWs, due to both the decrease of thickness and the addition of the annealing stage of the ZnO seed layers, allows room for hope when it comes to their integration into our energy harvesting technologies for the improvement of their electrical performances [45]. However, the coalescence of the NWs can limit the mechanical compression along the c-axis of the NWs [46] and cause internal screening effects [47], leading to reduced piezoelectric potential, and thus lower nanogenerator performances.…”

Piezoelectric Biomaterials for Sensors and Actuators

“…New classes of composite piezoelectric materials tend to combine different advantages of inorganic materials (e.g., high piezoelectricity) and organic materials (e.g., flexibility). Recent developments in piezoelectric nanocomposite–based biomedical devices have shown various applications for these materials . Organic–inorganic hybrid nanogenerators are very promising for various applications ranging from flexible wearable electronics to human–machine interfaces …”

Effect of the excitation waveform on the average power and peak power delivered by a piezoelectric generator

“…The study detailed in this part is the case of a PG having a capacitive internal impedance such as a nanowire-polymer composite generator with a vertical configuration [2,16,23,24] or lateral configuration [25,26]. We consider first a lossless capacitive impedance (which means that the dielectric losses angle tan δ is null), but the formula can be applied to any type of lossy capacitive and/or p − n junction generator [27,28].…”

“…The value of the internal impedance does not change the results obtained is that study, a sensitivity analysis is presented later in the manuscript. The chosen fundamental frequency is 5 Hz since most of our PG characterization campaigns are made at this frequency [23,29]. The model derived in this paper works even if the fundamental frequency is modified, provided that we stay in the quasi-static regime or at least far away from resonance modes.…”