Conductive hydrogels are attracting considerable interest in view of their potential in a wide range of applications that include healthcare and electronics. Such hydrogels are generally incorporated with conductive materials/polymers....
To fabricate a high‐performance and ultrasensitive triboelectric nanogenerator (TENG), choice of a combination of different materials of triboelectric series is one of the prime challenging tasks. An effective way to fabricate a TENG with a single material (abbreviated as S‐TENG) is proposed, comprising electrospun nylon nanofibers. The surface potential of the nanofibers are tuned by changing the voltage polarity in the electrospinning setup, employed between the needle and collector. The difference in surface potential leads to a different work function that is the key to design S‐TENG with a single material only. Further, S‐TENG is demonstrated as an ultrahigh sensitive acoustic sensor with mechanoacoustic sensitivity of ≈27 500 mV Pa–1. Due to high sensitivity in the low‐to‐middle decibel (60–70 dB) sounds, S‐TENG is highly capable in recognizing different voice signals depending on the condition of the vocal cord. This effective voice recognition ability indicates that it has high potential to open an alternative pathway for medical professionals to detect several diseases such as neurological voice disorder, muscle tension dysphonia, vocal cord paralysis, and speech delay/disorder related to laryngeal complications.
Ferroelectric δ‐phase comprising polyvinylidene fluoride (δ‐PVDF) thin films are prepared via spin‐coating followed by high‐temperature annealing and rapid ice quenching, where, the requirement of a high electric field (~MV/m) is circumvented. Herein, ferroelectric responses, that is, “write,” “erase,” and “read” pulses on as prepared δ‐PVDF thin film, have been demonstrated through piezoresponse force microscopy (PFM). A metal‐ferroelectric‐insulator–semiconductor (MFIS) diode containing δ‐PVDF has shown a capacitance–voltage (C–V) hysteresis with a notable memory window of 7.5 V up to a temperature of 140°C, overcoming lower fatigue temperatures, limited by Curie transition in co‐polymer P(VDF‐TrFE). A very stable polarization state is reflected by a holding period of a capacitance state of 10 h, where only a 5% loss of its initial value is noticed. The excellent ferroelectric response and retention behavior of the δ‐PVDF thin film may open up new opportunities in the field of high‐endurance non‐volatile memories.
Organic nonvolatile memory with low power consumption is a critical research demand for next-generation memory applications. Ferroelectric switching characteristics of poly(vinylidene fluoride) (PVDF) thin films modified with a trace amount of hydrated Cu salt (CuCl2·2H2O) are explored in the present study. Herein, a Cu salt-mediated PVDF (Cu/PVDF) thin film with preferential edge-on β-crystallites is fabricated through the orientation-controlled spin coating (OCSC) technique. This work proposes a convenient and effective approach to produce edge-on-oriented electroactive PVDF thin films with a high degree of polar β-phase, so as to realize the favorable switching under low operating voltages. Herein, chemically modified PVDF is anticipated to form a complex intermediate, which attains its stability by undergoing favorable hydrogen bonding that reorients the C–C structure of PVDF to obtain the β-conformation. Such information is verified by X-ray photoelectron spectroscopy (XPS). Grazing incidence Fourier transform infrared (GI-FTIR) spectroscopy revealed that the Cu salt incorporated into the PVDF matrix favored the formation of the electroactive β-phase with edge-on crystallite lamellae. Consequently, the Cu/PVDF thin film demonstrates a good contrast between electric field-assisted written and erased data bits in the piezoresponse force microscopy (PFM) phase image. Furthermore, to obtain the ferroelectric memory window, a metal–ferroelectric–insulator–semiconductor (MFIS) diode with Cu/PVDF as a ferroelectric layer has been fabricated. The capacitance–voltage (C–V) characteristic of the MFIS diode exhibits a memory window of 12 V with a long-term retention behavior (∼longer than 7 days). In a nutshell, we tried to represent a clear understanding of the interfacial interactions of the Cu salt with PVDF, which favor the edge-on formation that results in the promising low-voltage ferroelectric switching and excellent retention response, where any additional electrical poling and/or external stretching is completely possible to be ruled out, thus offering a new prospect for the evolution of devices with long-lasting nonvolatile memories.
extensive investigation due to their prospective applications in the field of internet of things, robotics, biological sectors, and piezo-phototronics. [1][2][3][4][5][6][7][8] All organic functional polymers have drawn crucial attention due to its inherent flexibility, lightweight, surface potential tunability, and easy processing for different additive manufacturing techniques (e.g., spray coating, screen printing, inkjet printing, etc.). [9] Besides, self-powered optoelectronic devices are also rapidly gaining the attention due to their superior electronic and optical properties for the next generation wearable electronics. In this context, the piezo-phototronic properties are promising since the induced piezo-potential at the junction can possible to use to modulate the generation, separation, and recombination of charge carriers at the interface of electrode and material. [10] Therefore, a new avenue toward piezotronics and piezo-phototronics is developed by connecting piezoelectric, semiconducting, and photoresponsive properties. [11] In the past few years, the piezo-phototronic effect of various inorganic piezoelectric semiconducting materials, e.g., zinc oxide (ZnO), gallium nitride (GaN), zinc stannate (ZnSnO 3 ), cadmium selenide (CdSe), cesium lead bromide (CsPbBr 3 ), 2D chalcogenides such as molybdenum disulfide (MoS 2 ), tin selenide (SnSe), and indium selenide (InSe) have been explored so far. [12][13][14][15][16][17][18][19] However, these materials have several drawbacks because of the challenging synthesis process, steep cost, brittleness, large area device fabrication, and scalability. In this concern, organic electroactive polymers, such as polylactide, odd nylons, poly(lactic-co-glycolic acid), poly(vinylidene fluoride) (PVDF), and its co-polymers are attracting for smart active materials. [20] Among them, PVDF and its copolymers are regarded as a suitable alternatives because of their outstanding piezo-, pyro-, and ferro-electric properties arising from electroactive phase(s). [21,22] It is a semi-crystalline polymer that possesses different polymorphic phases, e.g., α, β, γ, and δ depending upon their macromolecular chain orientation. Among them α-phase is non-electroactive (due to the net dipole moment per unit cell is zero) and other phases are electroactive in nature. These electroactive properties are attributed from the crystalline part of PVDF.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.