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This work explored an MWCNT-incorporated natural rock-based (hematite) multifunctional piezo-responsive nanocomposite for the simultaneous degradation of carcinogenic dyes and generation of non-invasive energy. The enhanced polar phases of the nanocomposite membrane were verified using XRD, FESEM, FTIR, and density functional theory (DFT), which is responsible for elevating the piezoelectric property of the synthesized composite. Further, a flexible and free-standing device was fabricated using this membrane and employed to generate piezoelectric power (8.684 mW cm−3) with an instantaneous open circuit piezo voltage of 53.9 V and short circuit piezo current of about 11.6 μA under feeble finger tapping (16.3 N). This piezoelectric device produces energy from different non-invasive mechanical vibrations, such as water flow and wind energy. Under ultrasonic activation, the synthesized nanocomposite membrane could aid in various reactive oxygen species (ROS) that degrade carcinogenic organic pollutants, such as Rhodamine B (RhB) dye, in just 30 min with an efficacy of 98.7%. In summary, this work delves into a modified natural rock-based multifunctional biocompatible, self-poled polymeric nanocomposite membrane instead of conventional chemically derived piezo-active nanoparticles for non-invasive energy generation and harmful organic dye degradation for sustainable development. [ABSTRACT FROM AUTHOR]

Recent advancements in wireless, flexible, and self-powered sensors have opened avenues for real-time monitoring of mechanical pressure stimuli at remote locations with utmost resolution and precision. This work reports on the development of a 2-D MoO3/PVDF–HFP composite-based flexible and highly efficient piezoelectric nanogenerator (PNG). The influence of 2-D α-phase MoO3 (α-MoO3) nanoflakes on the polymorphism of poly-(vinylidene fluoride-co-hexa-fluoropropylene) (PVDF–HFP) was systematically investigated with the aim of maximizing the electroactive β phase. A series of α-MoO3 nanoflakes-incorporated flexible, transparent, and self-standing PVDF–HFP composite films with varying loading weight percentages of 1, 1.5, and 2% (PMO1, PMO1.5, and PMO2, respectively) were prepared by the solution casting technique. PMO2 exhibited a high β-phase fraction of 76% and was used to fabricate a facile and flexible PNG device. Gentle finger tapping onto the PNG showed an excellent open-circuit output voltage (50 V across 30 MΩ resistance) with a maximum power density of 1512 W m–3 and a conversion efficiency of 30.4%. The PNG demonstrated a promising performance for qualitatively detecting dynamic pressure stimuli. It was able to precisely monitor and discriminate the bending motion of different fingers and fine motions of proximal interphalangeal and metacarpophalangeal joints of the index finger. A (4 × 4) sensing matrix comprising the PNG was successfully employed to detect the spatial distribution of static pressure stimuli (with a sensitivity of ∼15.5 MPa–1), and the developed matrix was able to precisely record the shape and size of the objects placed onto it. The PNG-based sensor was also integrated with an android mobile interface through wireless technology for remote sensing applications. Hence, the fabricated PNG can be a promising device for wireless monitoring of mechanical pressure stimuli in different cutting-edge technologies such as healthcare monitoring, robotics, and wearable electronics. [ABSTRACT FROM AUTHOR]

With applications in robotic technology, human-machine interfaces and healthcare unit, the self-powered wearable triboelectric nanogenerator has the ability to detect different physical parameters. These aspects continue to be incredibly exciting for the researchers. Herein, a self-powered, skin-attachable and flexible triboelectric nanogenerator (EPMTNG) is designed with a charge generating layer using micro-patterned BaTiO3@Ecoflex (EBTO) nanocomposite, nanofibrous trapping layer with 2D MoTe2 and carbon tape as a charge collecting layer. Furthermore, charge recombination becomes the significant issue, which not only reduces the surface potential but also diminishes the output performance of TENG. For this, a 2D transition metal dichalcogenide (MoTe2) incorporated PVDF nanofibrous (PM5) layer is introduced as a charge trapping layer to prevent the charge recombination and improve the output performance of the device. Additionally, the incorporation of 2D MoTe2 nanoparticles reinforces the polarization effect by gathering more charge carriers and improves the dielectric property and conductivity of the device. To establish our concept of inclusion of an intermediate trapping layer in EPMTNG, a theoretical simulation model has been prepared confirming the rise of surface potential and output voltage in the presence of the trapping layer. Along with this, a surface modification technique has been resorted to create surface roughness and improve the output performance of EPMTNG. Thus, the intermediate trapping layer and micro-patterned nanocompositebased EPMTNG device generate a colossal output voltage of 319 V and an instantaneous power density of 2.9 W m−2 under an axial pressure of 12 N. Also, the high sensitivity (32.5 V kPa−1) of the device at low-pressure region assists in successfully detection of robotic gestures, including artificial finger bending and objects gripping. Moreover, the flexibility and skin attachable properties encourage the EPMTNG device in tracking human physiological signals coming from blood flow, glottis movement, neck up down, wrist bending, etc., and monitor the wireless transmission of these signals. Therefore, the self-powered flexible device may be useful in health monitoring units and soft robotics applications. [ABSTRACT FROM AUTHOR]

Energy demand is increasing exponentially nowadays, which is the primary cause of the burning of fossil fuels, creating enormous amounts of environmental degradation. To arrest this, there is an emerging need for clean and green technologies. Herein, piezoelectric materials have become a favourite choice among scientists. Previously, many groups have exploited this fascinating technology by imparting pressure from different available sources. This article deals with gadolinium (Gd)-incorporated naturally occurring hematite nanocrystals, which show an efficient piezoelectric effect when incorporated into a PVDF-HFP polymer. In reality, PVDF-HFP is capable of producing nominal piezoelectric polarization (40–60% β-polarization), which in our case is found to be around 80.3%. Such elevated polarizability helps to generate piezoelectric power under water flow or finger tapping. This reported material is not only flexible and bendable but can also produce maxima of 16.92 V and 0.52 μA instantaneous voltage and current, respectively, under simple finger tapping, but 8 V under flowing water. Moreover, these phenomena have been discussed and analyzed in great depth by involving various characterization tools such as XRD, FESEM, TEM, FTIR, and zeta potential. This is probably the first time that a rare-earth-incorporated natural nano-rock mineral has been used to fabricate such a multifunctional device. [ABSTRACT FROM AUTHOR]

This work reports a solvothermal synthesis of ferromagnetic bismuth ferrite (BFO) nanoparticle and its piezo activity in the domain of catalytic degradation of carcinogenic and genotoxic rhodamine B (RhB) dye and pathogenic Escherichia coli bacteria as well. After synthesis and characterization, the structural and morphological features of the catalyst were further investigated using density functional theory (DFT), which enabled us to estimate the polarizability and many other important electrical properties of the synthesized material. The DFT study reveals remarkably high polarizability and dipole moment, which were utilized to validate the generation of piezo response by the synthesized material. Interestingly, we found enhanced piezo catalytic degradation efficiency (η ∼ 99%) along with a high rate constant (k ∼ 2.259 × 10−2 min−1), indicating a fast and efficient degradation process. In the case of pathogenic bacteria E. coli, the degradation efficacy was found to be ∼94%. Moreover, the extraction of this catalyst is quite simple. Due to its high remanent magnetization (retentivity ∼0.08 emu g−1), the catalyst can be extracted from the treated water sample by using external magnetic stimulation, making it a potential candidate for sustainable wastewater treatment. [ABSTRACT FROM AUTHOR]