Aluminum impregnated zinc oxide engineered poly(vinylidene fluoride hexafluoropropylene)-based flexible nanocomposite for efficient harvesting of mechanical energy

Confronting the depletion of fossil fuel energy as well as pollution generated from chemical batteries, associated with the increasing number of electronic equipment and the internet of things, results in a high requirement of lightweight, low cost, sustainable, and durable power devices. Currently, a flexible and self-powered piezoelectric energy harvester (PZEH) is a suitable alternative, which may be easily integrated with small electronics to realize real-time sustainable energy generation. Therefore, a novel PZEH has been fabricated at room temperature (30 degrees C) using Al-doped ZnO (Al@ZnO) incorporated poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) nanocomposites. Al@ZnO enables nucleation of electroactive phase within PVDF-HFP (10PALZO) exhibited polarity at a much higher fraction (FEA] >90%) compared to neat PVDF-HFP (FEA] = 63.8%). Piezoelectric energy harvesting capability of the device has been investigated under gentle repeated human finger tapping. Optimized Al@ZnO-PVDF-HFP composite (with 10 wt% loading)-based PZEH delivered a high value of open-circuit output voltage similar to 22 V. Such high output value infers a good energy conversion efficiency of the device. For further enhancement of the performance of the device, the 10PALZO nanocomposite was placed under a high electric field of 2.4 MVcm(-1) resulting in an open circuit output voltage of similar to 26 V. In addition to that, the proposed nanocomposite exhibits a good energy storage efficiency (10PALZO-P) which further enhanced to 111.2 mu Jcm(-3) (at 1 Hz) after poling under an electric field 2.4 MVcm(-1). This increment in the output value is due to the improved polarization induced by Al@ZnO within the PVDF-HFP matrix. These results highlight that the filler can efficiently maximize the device performance thereby developing new efficient energy harvesting materials

SiO2 Nanoparticles Incorporated Poly(Vinylidene) Fluoride Composite for Efficient Piezoelectric Energy Harvesting and Dual-Mode Sensing

Flexible electronic skins (e-skins) have a wide range of applications in health monitoring, human-machine interfaces, and robotics. Herein, a novel architecture of e-skins with a combination of multimode measurement and low-cost implementation is proposed. A single electronic skin layer is used to integrate both the pressure and temperature sensing properties. An e-skin membrane is first developed with poly(vinylidene) fluoride incorporated with silicon dioxide nanoparticles. When combined with electrodes, this simple architecture allows the implementation of multimode pressure and temperature sensing. This e-skin exhibits excellent pressure sensitivity with a response time of 1.6 ms. This sensing performance can be attributed to the uniform distribution of the embedded nanoparticles, leading to an enhancement of the electroactive beta phase. This e-skin generates a voltage, from the finger movements, that can be used to detect precisely the minute changes of the finger movement. This electronic skin demonstrates the detection of a linear range of temperature which can be attributed to the phonon-assisted hopping mechanism. A 4 x 4 pressure sensing array is demonstrated, which is able to map the inserted pressure as well as temperature stimuli. Thus, this study provides a new conceptual design for the next-generation green electronic skins

Tailored piezoelectric performance of self-polarized PVDF-ZnO composites by optimization of aspect ratio of ZnO nanorods

Aspect ratio of filler plays a crucial role to study the electrical properties of polymer based composite system. Here, we investigated the effect of filler aspect ratio on the electrical properties of zinc oxide (ZnO) incorporated poly(vinylidene fluoride) (PVDF) matrix. ZnO nanorods having different aspect ratio were synthesized by the hydrothermal technique with varying reaction time 4 to 20 hours at a fixed temperature and PVDF based nanocomposites of the respective ZnO nanorods with different wt% filler loading were fabricated. Interestingly polar-phase fraction increased with the aspect ratio of ZnO nanorods. The nanocomposites with higher aspect ratio ZnO nanorods showed an increased energy density under same electric field and exhibited maximum open circuit AC output voltage (ie, 20 V) after the application of repeated human finger tapping. This result indicates that high aspect ratio ceramic filler provides an effective approach to enhance the dielectric, ferroelectric, energy storage, and energy harvesting performances of ceramic-polymer nanocomposites

Multiferroic BiFeO3-based hydrophobic polymer composites for polarization rationalization-induced piezo-tribo hybrid energy harvesting and versatile self-powered mechanosensing

BiFeO3-poly(vinylidene fluoride) (BFO-PVDF) and BiFO3-polydimethylsiloxane (BFO-PDMS) piezoelectric composite films have been fabricated herein and used to develop flexible piezoelectric-triboelectric hybrid nanogenerators by forming different combinations with aluminium (Al) electrodes (PVDF-Al, PDMS-Al and PDMS-PVDF) using the contact-separation mode. The dielectric permittivity of both the PVDF- and PDMS-based composites has been found to increase from similar to 9 and 3.2 for a filler loading of 3 wt% to similar to 16.6 and 4.7, respectively, for 10 wt% BFO concentration within their matrix. The mechanical stimulus-driven output voltage has also been found to be increased from similar to 7.5 V and 35 V to similar to 18 V and 100 V for the respective films. The rational augmentation of the polarization of PVDF and PDMS induced by the gradually increased BFO filler concentration in their matrix, as confirmed from the above-mentioned results, have been found to significantly affect the output performance of the fabricated piezo-tribo hybrid nanogenerators. Among the three types of fabricated hybrid devices, the combination of 10 wt% BFO-incorporated PDMS with an aluminium electrode shows the best output performance both theoretically and experimentally. Hence, this combination has been used to develop a flexible multi-unit hybrid nanogenerator (M-HNG), which shows further performance enhancement (output power density: similar to 600 mu W cm(-2)). The M-HNG was then used for biomechanical energy harvesting, powering small electronics and different self-powered mechanosensing applications including motion sensing, pressure sensing, water drop counting and phonation monitoring

Nature-Driven Biocompatible Epidermal Electronic Skin for Real-Time Wireless Monitoring of Human Physiological Signals

Wearable bioelectronic patches are creating a transformative effect in the health care industry for human physiological signal monitoring. However, the use of such patches is restricted due to the unavailability of a proper power source. Ideal biodevices should be thin, soft, robust, energy-efficient, and biocompatible. Here, we report development of a flexible, lightweight, and biocompatible electronic skin-cum-portable power source for wearable bioelectronics by using a processed chicken feather fiber. The device is fabricated with a novel, breathable composite of biowaste chicken feather and organic poly(vinylidene fluoride) (PVDF) polymer, where the chicken feather fiber constitutes the ``microbones'' of the PVDF, enhancing its piezoelectric phase content, biocompatibility, and crystallinity. Thanks to its outstanding pressure sensitivity, the fabricated electronic skin is used for the monitoring of different human physiological signals such as body motion, finger and joint bending, throat activities, and pulse rate with excellent sensitivity. A wireless system is developed to remotely receive the different physiological signals as captured by the electronic skin. We also explore the capabilities of the device as a power source for other small electronics. The piezoelectric energy harvesting device can harvest a maximum output voltage of similar to 28 V and an area power density of 1.4 mu W center dot cm-2 from the human finger imparting. The improved energy harvesting property of the device is related to the induced higher fraction of the electroactive phase in the composite. The easy process ability, natural biocompatibility, superior piezoelectric performance, high pressure sensitivity, and alignment toward wireless transmission of the captured data make the device a promising candidate for wearable bioelectronic patches and power sources

Nature-Driven Biocompatible Epidermal Electronic Skin for Real-Time Wireless Monitoring of Human Physiological Signals

Wearable bioelectronic patches are creating a transformative effect in the health care industry for human physiological signal monitoring. However, the use of such patches is restricted due to the unavailability of a proper power source. Ideal biodevices should be thin, soft, robust, energy-efficient, and biocompatible. Here, we report development of a flexible, lightweight, and biocompatible electronic skin-cum-portable power source for wearable bioelectronics by using a processed chicken feather fiber. The device is fabricated with a novel, breathable composite of biowaste chicken feather and organic poly(vinylidene fluoride) (PVDF) polymer, where the chicken feather fiber constitutes the ``microbones'' of the PVDF, enhancing its piezoelectric phase content, biocompatibility, and crystallinity. Thanks to its outstanding pressure sensitivity, the fabricated electronic skin is used for the monitoring of different human physiological signals such as body motion, finger and joint bending, throat activities, and pulse rate with excellent sensitivity. A wireless system is developed to remotely receive the different physiological signals as captured by the electronic skin. We also explore the capabilities of the device as a power source for other small electronics. The piezoelectric energy harvesting device can harvest a maximum output voltage of similar to 28 V and an area power density of 1.4 mu W center dot cm-2 from the human finger imparting. The improved energy harvesting property of the device is related to the induced higher fraction of the electroactive phase in the composite. The easy process ability, natural biocompatibility, superior piezoelectric performance, high pressure sensitivity, and alignment toward wireless transmission of the captured data make the device a promising candidate for wearable bioelectronic patches and power sources

Enhanced dielectric, ferroelectric, energy storage and mechanical energy harvesting performance of ZnO-PVDF composites induced by MWCNTs as an additive third phase

The present work highlights an attempt of fabricating a nanocomposite by the addition of multi-walled carbon nanotubes (MWCNTs) as a third phase into flexible ZnO-poly(vinylidene fluoride) (ZnO-PVDF) composites. MWCNTs played a very important role in distributing ZnO fillers in the PVDF matrix more homogeneously and increased the connection capability. Enhancement of the piezoelectric phase, dielectric permittivity, ferroelectric polarization, energy storage density and mechanical energy harvesting performance of ZnO-PVDF composites after the addition of MWCNTs was confirmed from the respective characterization studies. The sensing capability was demonstrated by the generation of similar to 22 V ac output voltage through the application of human finger tapping on 15 wt% ZnO and a 0.1 wt% MWCNT-loaded PVDF (15PZNT) based composite film. The rectified voltage from the fabricated 15PZNT film was used to charge a 10-mu F capacitor up to similar to 3 V which was used for the illumination of 30 commercial LEDs. The maximum power density from the film was found to be 21.41 mu W cm(-2) at 4 M omega load resistance. The effect of the addition of MWCNTs was also verified by simulation using COMSOL Multiphysics software

Boron doped SiC thin film on Silicon synthesized from polycarbosilane: a new lead free material for applications in piezosensors

In this paper, we are reporting for the first time, the piezosensing characterisations of the SiC thin film on silicon, synthesized from boron containing Liquid Polycarbosilane (PCS) as a precursor deposited by Modified Chemical Vapour Deposition (MoCVD) technique followed by the structural characterisation of the film. Comparison was done on the result of the both undoped and doped SiC thin film to highlight the effect of boron doping on the piezo property of the SiC. Interestingly, it was observed that piezoelectric coefficient (d(33)) of the boron doped SiC thin film was substantially higher (21.33 pm/V) than the undoped SiC thin film (16.21 pm/V). The enhancement in d(33) was analysed considering the polarisation inside the thin film created by boron doping. The result shows a promising boron doped SiC thin film material for the application in high temperature piezo sensors