Figure - available from: Journal of Materials Science
This content is subject to copyright. Terms and conditions apply.
a Hydrothermal synthesis of KNN nanorods, b surface modification of the synthesized KNN using three different surface modifiers and c schematic line diagram of nanocomposite films formation by solution cast method
Source publication
![a Surface morphology of the synthesized KNN nanorods [22], b diameter...](publication/333443024/figure/fig3/AS:779419455082500@1562839487146/a-Surface-morphology-of-the-synthesized-KNN-nanorods-22-b-diameter-distribution-of-the_Q320.jpg)
The demand of self-powered electronic devices has stimulated a great interest in daily life. To fulfill this, thrust researchers are engaged to develop different piezoelectric self-powered-based devices. The piezoelectricity is broadly dependent on the electroactive phase of the polymer structure. Herein, lead-free potassium sodium niobate (KNN) na...
Similar publications
In this study, Nanoparticle synthesized zinc oxide (ZnO) and copper oxide (CuO) in (PVP) polyvinylpyrrolidone as a dispersing agent with a simple chemical reaction used for the antimicrobial activity. Various concentrations of metal oxide with PVP synthesis as (0.02, 0.05, 0.1, and 0.4) M. The result of the x-ray diffraction indicated the presence...
Quench hardening aims at the microstructural transformation of steels in order to improve hardness and mechanical strength. The aim phase is, in most cases, the martensite. It is necessary to heat the material until it obtains its austenitization and quenching by immersion in a fluid. Currently, it is common to use watery polymeric solutions in thi...
Polyvinylpyrrolidone Oxime (PVPO) was synthesized and studied for mild steel (MS) corrosion inhibition in 1 M H2SO4, at different concentrations and temperatures. The corrosion inhibition efficiency was studied using weight loss method, polarization technique, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and quan...
Polymer electrolytes were prepared by doping polyvinylpyrrolidone and ammonium iodide ion with an ionic liquid (IL) 1-hexyl-3-methylimidazolium iodide. Polymer electrolytes were prepared by solution cast technique. Ionic conductivity was improved by the addition of IL which is studied using complex impedance spectroscopy by evaluating ionic conduct...
Citations
... The dimensional changes in a piezoelectric material as a response to an applied electric field is called the converse piezoelectric effect [13]. Piezoelectric materials can be classified as single crystals, polymers, ceramics and composites [14][15][16][17][18]. Each of these categories of materials have unique characteristics that are explored in a wide variety of applications. ...
In this current energy crisis era, piezoelectric and triboelectric effects are emerging as promising technologies for energy harvesting. Polyvinylidene fluoride (PVDF) and its copolymers are well-known piezoelectric materials with high piezoelectric coefficients, which are widely used in flexible electronic devices. PVDF is also greatly utilized in the preparation of triboelectric layer due to its higher electronegative nature amongst common polymers. On the other hand, zinc oxide (ZnO) has been widely studied to investigate its multifunctional properties, including piezoelectricity, pyroelectricity and antibacterial activity. This versatile material can be prepared, using low cost and environmentally friendly routes, in various morphologies. Various research has already been performed to capture the synergistic effects of reinforcing ZnO within the PVDF polymeric matrix. This work first describes the basic principles of piezoelectric and triboelectric effects. Thereafter, the piezoelectric and triboelectric performances of PVDF and ZnO-based materials are briefly depicted based on their structures. Finally, the challenges and future scope associated with the mechanical energy harvesting from such materials are highlighted.
... KNN has an ABO 3 perovskite structure [12]. It is a composition in a 1:1 ratio of ferroelectric and antiferroelectric, KNbO 3 and NaNbO 3, respectively [12,13]. ...
... spectra obtained for KNN: xEr (x = 0, 1, 2, 3, and 4) are represented in Fig. 4a. The high-intensity transmittance band at 486 cm −1 is accredited to the stretching and bending of the NbO 6 bond [13]. The less dominant band at 720 cm −1 is attributed to the oxygen octahedral which are the characteristic peaks of KNN [12]. ...
... The dopant concentration reaches an edge where the distance between erbium (dopant) ions becomes so minute that their energy transference becomes simpler, contributing to nonradiative relaxation. The radiative transitions reduce; hence the strength of the PL emissions diminishes [13]. Figure 6c shows the mechanism of the down-conversion process of Er 3+ ions under the excitation of 488 nm. ...
The lead-free ceramics K0.5Na0.5NbO3: x wt% Er³⁺ (x = 0, 1, 2, 3 and 4) were produced via solid-state method. The ceramic was sintered at 1100 °C to produce a pure-phase perovskite with an orthorhombic structure. No extra phases in the XRD spectra demonstrate that all the Er³⁺ ions have dispersed into the host lattice. At room temperature, PL emission spectra were examined under the wavelengths 488 and 980 nm. In both emission spectra, green emission bands (528 and 549 nm) and slightly faint red emission bands (662 nm) were found. Observing the effect of pump power revealed that two photons are involved in the emission process. The time decay profile indicates an average lifetime of Er³⁺ ions is 25.05 μs. The ferroelectric hysteresis loop at room temperature showed decent shapes with good remnant. Thus, by combining the optical and ferroelectric properties, KNN may have potential applications to be employed in optoelectronic devices.
... But they normally suffer from flexibility and fabrication processing despite the high piezoelectric coefficients [11]. Researchers have recently become interested in the improvement of polymer's dielectric, ferroelectric, piezoelectric, and electrical energy storage capabilities by incorporating ceramic filler particles into its matrix [12][13][14][15][16][17][18] 3 , and BiFeO 3 ) have been used to improve piezoelectric characteristics of polymer [11][12][13][14][15][16]. BFO has been shown to be a decent choice as a potential component to build composites due to its high ferroelectric transition temperature (T c = 830 °C) and Neel temperature (T N = 370 °C) [19,20]. ...
... But they normally suffer from flexibility and fabrication processing despite the high piezoelectric coefficients [11]. Researchers have recently become interested in the improvement of polymer's dielectric, ferroelectric, piezoelectric, and electrical energy storage capabilities by incorporating ceramic filler particles into its matrix [12][13][14][15][16][17][18] 3 , and BiFeO 3 ) have been used to improve piezoelectric characteristics of polymer [11][12][13][14][15][16]. BFO has been shown to be a decent choice as a potential component to build composites due to its high ferroelectric transition temperature (T c = 830 °C) and Neel temperature (T N = 370 °C) [19,20]. ...
The enhancement of Piezo response and local ferroelectric behavior of PVDF-Bi25FeO40 composite thin films are investigated using piezo force microscopy (PFM) technique. The self-assembled composite nanodots thin films are prepared by spin coater with PVDF and Bi25FeO40 nano powder solution mixture. The structural and morphology characteristics are analyzed by FTIR-ATR and Atomic force microscopy. The surface microstructure, confined domain structure, its piezo, ferro electricity behavior, its corresponding d33 coefficient are explored with PFM under no poling and poling with external DC bias, AC bias and various drive frequencies. The d33 coefficient varies from 14 to 17 pm/V by adding of 5 wt% of Bi25FeO40 to PVDF than pristine PVDF nanodots made under same condition.
... KNN nanorods were synthesized by hydrothermal reaction by employing the optimized parameters as reported in our previous study [21]. To summarize, initially 0.006 mol of Nb 2 O 5 was added into the blend solution (1:5) of KOH and NaOH, while continuously stirring the mixture for two hours to maintain an overall molar solution of 14 mol/L. ...
High-temperature stable eco-friendly energy-harvesting technologies are in high demand for industrial applications wherein piezoelectric energy harvesting is gaining interest. The present work describes a high-temperature stable electrospun nanofiber-based flexible piezoelectric nanogenerator (PENG). A lead-free piezoelectric filler potassium sodium niobate (KNN) is incorporated in polyetherimide (PEI) matrix through an electrospinning process. A polymeric solution of PEI in 1-methyl-2-pyrrolidone (NMP) solvent is prepared at a fixed concentration of 25 wt% and filler loading varied from 1 to 3%. Among the various percentages of KNN NRs, 2% KNN NRs @ PEI nanocomposite demonstrates the most promising results (voltage of 6.3 V and current of 0.60 μA). In addition, the flexible nanogenerator holds its piezoelectric performance even at very high temperatures (studied up to 250 ºC) without any significant deterioration in properties. Finally, the optimized piezoelectric nanogenerator (PENG) is used to charge capacitor and glow LED. Therefore, the flexible nanogenerator prepared with 2% KNN NRs @PEI has huge potential to be explored as piezoelectric sensors or energy harvesters in high-temperature stable applications wherein the conventional piezoelectric polymers like PVDF and other thermoplastics fail to sustain their piezoelectric response.
Graphical abstract
... Silylation reaction usually uses the SiOH group hydrolyzed by trimethoxysilyl or triethylsilane-based elastomers to modify the surface of nano materials, primarily, 3-aminopropyltrimethoxysilane (APS), 3-trimethoxysilylpropyl methacrylate (TMSPM), γ-Glycidoxypropyltrimethoxysilane (KH560) and polydimethylsiloxane (PDMS) [54][55][56][57][58][59] . In the process of preparing piezoelectric nanocomposites, nanoparticles are easy to agglomerate and show poor affinity with the matrix. ...
... During this process, the silane coupling agent is coated onto nanoparticles to improve the interface interactions and compatibility between the nanoparticles and polymer matrix. Recently, Wang et al. demonstrated high-performance BaTiO 3 -PDMS composites for electromechanical energy conversion [54] . The maximum open-circuit output voltage and short-circuit current of dielectrophoretically aligned BaTiO 3 -PDMS composite reach ~80 V and ~25 μA, respectively. ...
Piezoelectric materials directly convert energy between electrical and mechanical domains, and have been widely employed in electronic devices as sensors and energy harvesters. Recent research endeavors are mainly devoted to dealing with problems such as high stiffness, brittleness, toxicity, poor durability, and low piezoelectric coefficients. Among developed strategies, chemical modification captures much attention. However, the exact physical properties and direct experimental evidence of chemical modification remain elusive or controversial thus far. In this review, we discuss the recently developed piezoelectric modification strategies for piezoelectric composites and assess the effect of different chemical modification approaches on piezoelectric properties. Moreover, we outline existing challenges and new applications of piezoelectric composites.
... The ceramic-based piezoelectric materials, namely lead zirconate titanate (PZT), sodium niobate (NB), barium titanate (BT) [4,5], zinc stannate (ZS) [6], potassium sodium niobite (KNN) [7][8][9][10] and so on, are the most explored ones. On the other hand, poly (vinylidene difluoride) (PVDF) and its co-polymers like poly (vinylidene difluoride trifluoroethane) (PVDF-TrFE), poly (vinylidene difluoride tetrafluoroethane) (PVDF-TFE) etc., have been used as a promising polymer-based piezoelectric material. ...
... There is also a significant increase in the intensity of C-H stretch vibration at 2932.71 cm -1 and 1230 cm -1 which is possibly due to interaction of inherent hydroxyl groups of copper oxide with the C-H of PAN [32]. Specifically, interaction takes place between hydroxyl group of copper oxide and CH 2 group corresponding to 3 1 -helical conformation of PAN, at the wavenumber of 1230 cm -1 [8,22]. There are peaks at 2245.21 cm -1 , 1629 cm -1 and 1732 cm -1 which are ascertained to nitrile groups, C = C and C = O stretch vibrations, respectively, present in PAN [32]. ...
Herein, a flexible light weight lead-free piezoelectric nanogenerator has been
fabricated using electrospun web based on polyacrylonitrile (PAN) and copper
oxide (CuO) nanorods. The influence of CuO nanorods on the piezoelectric
performance of PAN nanofibrous structure (in the form of a nanocomposite) has been investigated critically. Structural analysis of the electrospun nanocomposite has been done by FTIR and XRD techniques. Morphology of the developed material has been evaluated by scanning electron microscopy (SEM), whereas thermal behaviour has been investigated by thermogravimetric analyser (TGA) and differential scanning calorimetry (DSC). Finally, piezoelectric performance of the device has been measured by a digital oscilloscope. The piezoelectric nanogenerator (PAN/0.5% CuO) has shown an output voltage of ~5 V, current ~0.172 uA and power density ~0.215 uW/cm2 (when pressure is applied by finger tapping). The same nanogenerator has shown ~1.25 V and ~118 nA output voltage and short circuit current, respectively by using an automatic force-imparting machine. The fabricated nanogenerator is a potent device in lieu of the conventional battery powered devices.
... Ferroelectric materials are capable of storing energy upon charging and rendering some of it while discharging. Equations (8)- (10) can be used to calculate the stored energy (U s ), discharged or recovered energy (U d ), and the efficiency of a ferroelectric material using polarization curves [52,53]. ...
The emerging smart PVDF-based composites can compensate for the intrinsic property deficiencies in either of their components. The properties of the composite are determined by the properties of the constituents and its fabrication method. In this research, a lead-free piezoelectric ceramic, potassium sodium niobate (KNN), was used as the primary reinforcement, and MWCNTs were added to improve the electrical properties. Solution casting was used to prepare PVDF-KNN-CNT composite films. After phase and structure identification of composites using SEM, XRD, FTIR, and TGA methods, the dielectric, piezoelectric and ferroelectric properties of the products were investigated. The obtained results indicated a strong dependency of dielectric, piezoelectric, and ferroelectric properties of composites on KNN content. Samples with the highest KNN content rendered εr, d33 and g33 values of 156, 28 pC/N, and 20.32 mV m/N, respectively. Introducing a small amount of conductive CNT to primary PVDF-KNN composites can drastically affect the electrical properties by severely interfering in the charge distribution within the sample. While the dielectric constant was enhanced by increasing CNT content, both piezoelectric and ferroelectric properties showed their best behavior at a critical CNT loading. Beyond this limit, a percolation path formed, which is responsible for power consumption. At the optimum CNT amount, d33 and g33 reached 50 pC/N and 31.93 mV m/N, respectively. The presence of conducting CNTs gave rise to the formation of more round polarization curves with higher remnant polarization. The present findings give a prospective understanding of smart piezoelectric polymer-based composites that can be used as sensors and energy harvesters.
... A flexible, low-cost, lightweight PENG was then fabricated, by incorporating KNN nanoblocks into the poly vinylidene fluoride (PVDF) matrix. Here, PVDF was employed as a host matrix to stabilize the KNN nanostructures [55][56][57], due to its remarkable electroactive properties, excellent flexibility and cost-effective fabricating process. The PENG thus generated was then encapsulated by polydimethylsiloxane (PDMS) to make the device mechanically robust and stable. ...
With the tremendous growth of flexible piezoelectric nanogenerators, alkali niobates have gained considerable attention and are perceived to be the eco-friendly substitute for the unsustainable lead based piezoelectric systems. However, successful realization of potassium sodium niobate (KNN) based devices with appreciable piezoelectricity requires tailored molecular level organization. Herein, we have developed of a lead-free flexible piezoelectric nanogenerator based on KNN-PVDF nanocomposite, in which the KNN nanoblocks were synthesized using a novel non-aqueous surfactant-assisted hot injection method. Also, the synthesis of KNN employed non-toxic surface stabilizer, oleic acid and reaction catalyst, oleyl amine respectively, making the preparation environmental benign. The KNN nanoblocks homogeneously dispersed in the PVDF matrix up to 10 wt % filler loading, enhanced the piezoelectric and dielectric properties of the composite. Further, the fabricated flexible piezoelectric nanogenerator without any external poling process (size) exhibits an output open circuit voltage of ∼ 2.1 V and a short circuit current of 42 nA on a gentle finger tapping force (~3 N). The results demonstrate the potential of chemically engineered KNN nanoblocks dispersed in PVDF for large-scale sustainable piezoelectric nanogenerator applications.
... The FTIR study has further been performed to confirm the doping of KNN (Fig. 3c and d). The peak at 520 cm À1 corresponds to NbO 6 octahedron [12]. This peak shows a gradual shift and simultaneous broadening which suggests the incorporation of Zn and Sn into the lattice. ...
... The peak at around 614 cm À1 is due to the antisymmetric Sn-O-Sn mode [30,31] stretching. The peak at 3206 cm À1 is due to the eOH bond in the absorbed water molecule [12]. ...
With the increasing search for eco-friendly small-scale energy harvesting technologies, piezoelectric energy harvesting is gaining ground. Such technologies can be used to power small scale portable electronics, eliminating the need of batteries. In this study, a metal (Zn and Sn) doped potassium sodium niobate (KNN-ZS) piezoelectric filler has been synthesized through hydrothermal process. The doped KNN-ZS has a nanorod like structure with a high piezoelectric coefficient of ∼95 pC/N. The incorporation of this KNN-ZS filler in PVDF matrix through the electrospinning process, has produced nanocomposite fibrous web. A loading of 3% of the KNN-ZS filler has produced better structural and morphological properties as compared to 1% and 5% loading. The PVDF/3% KNN-ZS fibrous web has been used to fabricate a nanogenerator which can produce a piezoelectric output voltage of ∼1.68 V and an output current of ∼0.216 μA. Interestingly, the nanogenerator has also been tested for the combined triboelectric and piezoelectric effect. The combined output voltage has been observed as ∼25 V and that of current has been ∼2.11 μA. The synergistic performance of piezoelectric and triboelectric effect is well evident in the functioning of the nanogenerator. The harvested electrical charge (out of the fabricated nanogenerator) can be accumulated in a suitable capacitor and the same can be utilized in powering small scale electronics which would otherwise have to be powered by batteries.
... The r-GO shifted the melting temperature toward higher temperature (167.20 °C) at 0.1% concentration confirming the formation of nonpolar α-phase. [41,42] The further increase of concentration to 0.3% led to minimal shift of melting transition toward lower temperature (167.10 °C), which affirms that β-phase was highest at these concentration among the filler-loaded blends as determined by FTIR and XRD. The further increase in concentration to 0.5% led to agglomeration and formed stable α-phase crystallites. ...
Multifunctional piezoelectric nanocomposites are promising in terms of strain sensors and actuators having ability to switch their dimensional states in a programmed temperature depending on their chemical compositions. In this research work, the effect of immiscible blends of polyurethane and polyvinylidene fluoride to induce polar β‐phase in the melt extruded composite filament and the effect of reduced graphene oxide (r‐GO) in combined properties of piezoelectricity and shape memory behavior are studied with the aid of different characterization techniques. The thermal analysis by differential scanning calorimetry also reiterates the similar behavior of crystalline phases in melting transitions and compatibilization effect of r‐GO is well supported by field emission scanning electron microscopy. Moreover, some of these filaments possess promising shape memory behavior with recovery ratios up to 100%. One of the nanocomposite filament‐based energy harvesters generates average open circuit maximum voltage of ≈349 mV. These types of melt extruded nanocomposite filament‐based energy harvesters are promising in terms of miniaturized power sources fitting into different conformed surfaces having varied contours.
