Flexible piezoelectric nanogenerators for energy harvesting are getting more and more attention nowadays by converting the mechanical energy to electric energy. Here, an environment-friendly piezoelectric nanogenerator based on the regenerated cellulose (RC)/MoS2 nanosheet nanocomposite successfully exhibited a relative high output voltage of 2 V and current of 150 nA under slight press which were 5 and 7.5 times higher than those of the neat RC film, i.e. 0.4 V and 20 nA, respectively. In particular, the MoS2 nanosheets were obtained through a simple, facile and low-cost pathway by mechanical exfoliation in triethanolamine. The nanocomposite film with MoS2 nanosheets content of 4% exhibited a high piezoelectric constant (d33) of 19 pC/N, which was 6.3 times higher than that of the neat RC film (i.e. 3 pC/N). Thus, the RC/MoS2 piezoelectric nanogenerator has great potential applications in the fields of energy harvester, sensors and is of great significance to environment protection.
Need of renewable green energy sources due to low cost synthesis, mechanically strong, high energy storage capacity with improved dielectric performance have been receiving much attention. Present work render the ZnO particle and flower-like morphology assemble semicrystalline β phase PVDF/BT nanocomposite, successfully synthesized by spin coating method and characterized by XRD, SEM, EDS and FTIR techniques. Also the energy storage density of composite with modified structure is largely increased with value 0.056 Jcm−3 at 6 MV/m which is 66% higher than virgin β-PVDF and 82% piezoelectric energy harvesting efficiency. Maximum dielectric constant is 1774 at 1 Hz for PVDF-BaTiO3-ZnOf [P-BT-ZnOf] nanocomposite film and maximum breakdown strength of 43 kVcm−1. Electrochemical study reveals that P-BT-ZnOf nanocomposite film manifest better potential material. In terms of mechanical performance, P-BT-ZnOf nanocomposite shows maximum Young's modulus of 204 MPa, tensile strength of 28.7 MPa and 23.1% elongation to break. These results provide promising capability to enhance the performance of composites for energy storage application, transducers, sensors, capacitors etc. 相似文献
Multifunctional epoxy‐polydimethylsiloxane nanocomposite coatings with antifouling and anticorrosion characteristics have been developed via in situ polymerization method at different loading (1, 3, and 6.5 wt.%) of ZnO nanoparticles to cater marine applications. A detailed comparative analysis has been carried out between epoxy‐polydimethylsiloxane control (EPC) and ZnO‐reinforced coatings to determine the influence of ZnO loading on various properties. The incorporation of ZnO in EPC led to increase in root mean square (RMS) roughness to 126.75 nm and improved hydrophobicity showing maximum contact angle of 123.5° with low surface energy of 19.75 mN/m of nanocomposite coating as compared with control coating. The differential scanning calorimetry (DSC) result indicated improved glass transition temperature of nanocomposite coatings with highest Tg obtained at 83.69°C in case of 1 wt.% loading of ZnO. The increase in hydrophobicity of the system was accompanied by upgraded anticorrosion performance exhibiting 98.8% corrosion inhibition efficiency (CIE) as compared with control coating and lower corrosion rate of 0.12 × 10?3 mm/year. The Taber abrasion resistance and pull‐off adhesion strength results indicated an increment of 34.7% and 150.7%, respectively, in case of nanocomposite coating as compared with the control coating. The hardness of nanocomposite coatings was also improved, and maximum hardness was found to be 65.75 MPa for nanocomposite coating with 1 wt.% of ZnO. Our study showed that the nanocomposite coating was efficient in inhibiting accumulation of marine bacteria and preventing biofouling for more than 8 months. The developed environment‐friendly and efficient nanocomposite material has a promising future as a high‐performance anticorrosive and antifouling coating for marine applications. 相似文献
Undoped and manganese doped ZnO (ZnO:Mn) films were prepared by sol gel method using spin coating technique. The effect of
Mn incorporation on the structural and optical properties of the ZnO film has been investigated. The crystalline structure
and orientation of the films have been investigated by using their X-ray diffraction spectra. The films exhibit a polycrystalline
structure. Mn incorporation led to substantial changes in the structural characteristics of the ZnO film. The scanning electron
microscopy (SEM) images of the films showed that the surface morphology of the ZnO film was affected by the Mn incorporation.
The transparency of the ZnO film decreased with the Mn incorporation. The optical band gap and Urbach energy values of the
ZnO and ZnO:Mn films were found to be 3.22, 3.19 eV and 0.10, 0.23 eV, respectively. The optical constants of these films,
such as refractive index, extinction coefficient and optical dielectric constants were determined using transmittance and
reflectance spectra. The refractive index dispersion curve of the films obeys the single oscillator model with dispersion
parameters. The oscillator energy, Eo, and dispersion energy, Ed, of the films were determined 5.30 and 16.26 eV for ZnO film and 5.80 and 12.14 eV for ZnO:Mn film, respectively. 相似文献
Bio‐based nanocomposites of poly (butylene adipate‐co‐terephthalate) (PBAT)/silver oxide (Ag2O) were prepared by the composite film casting method using chloroform as the solvent. The prepared Ag2O at different ratios (1, 3, 5, 7, and 10 wt%) is incorporated in the PBAT. The PBAT nanocomposite films were subjected to structural, thermal, mechanical, barrier, and antimicrobial properties. The electron micrographs indicated uniform distribution of Ag2O in the PBAT matrix. However, the images indicated agglomeration of Ag2O particles at 10 wt% loading. The thermal stability of the nanocomposite films increased with Ag2O content. The tensile strength and elongation of the composite films were found to be higher than those of PBAT and increased with Ag2O content up to 7 wt%. The PBAT‐based nanocomposite films showed the lower oxygen and water vapor permeability when compared to the PBAT film. Antimicrobial studies were performed against two food pathogenic bacteria, namely, Klebsiella pneumonia and Staphylococcus aureus.相似文献
In this Communication, the effect of varying mass fractions (0–20 wt.‐%) of calcium chloride (CaCl2) salt on the α‐ and β‐phase content of poly(vinylidene fluoride) (PVDF) as‐cast films were investigated. Spectral and X‐ray studies revealed the maximum ferroelectric β‐phase for the addition of 15 wt.‐% of CaCl2 in PVDF compared to neat PVDF samples. The dense β‐phase dominant PVDF–CaCl2 (15 wt.‐%) thick film used as a ferroelectric insulator in one‐capacitor (1C) type random access memory device exhibited a remnant polarization of 3.1 µC · cm2, and is a good indication that the unoriented PVDF–CaCl2 films can be used in electronic applications without further stretching process.
In the recent era, finding renewable energy sources that are environmentally benign the main focus of scientific community around the globe. There is a plenty of renewable energy sources that are currently being researched such as solar power, thermal energy, wind energy, salinity gradients, and kinetic energy. Polymer‐ceramic–based nanocomposite piezoelectric material is known for quite some time for energy harvesting, but the real challenge lies as it requires very high loading of the ceramic part to obtain the required property and thus almost makes the system nonflexible. Developed material needs to be poled later on to use it as an electric energy generator from ambient mechanical movement. This current study is the first time attempt to produce a simple yet unique lightweight energy harvester using polyvinylidene fluoride (PVDF)/potassium sodium niobate (KNN) nanostructures–based nanocomposite flexible fibrous web where the material is in situ poled during its production using an electrospinning setup. At the beginning, various parameters were identified to synthesize and modulate KNN as nanostructural materials having higher aspect ratio, which is intended to provide a unique connection between KNN once these are embedded within the fibrous matrix. The incorporated KNN nanostructure having higher aspect ratio was also found to act as a beta nucleating agent in PVDF matrix and enhances the β‐phase crystal into the resultant fibrous web, which in turn increases the piezoelectric energy‐harvesting capacity manifold as compared with bare PVDF fibrous web. The in situ alignment of the nanostructured KNN (with a minimum loading, 5% only) into the fibrous nanocomposite is another achievement to obtain higher output. X‐ray diffraction and Fourier transform infrared analysis confirmed the mixture of α‐ and β‐crystalline phase of pure PVDF, which gets converted into β phase once KNN nanostructures are incorporated inside the nanofibrous web. An output voltage of 1.9 V was obtained from PVDF/KNN nanocomposite–based web, which is significantly higher (38 times) than generated voltage (50 mV) from the pure PVDF nanoweb without any subsequent poling operation. 相似文献
In this paper, we prepared TiO2@CdS core–shell nanorods films electrodes using a simple and low-cost chemical bath deposition method. The core–shell nanorods films electrodes were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV–vis spectrometry techniques. After applying these TiO2@CdS core–shell nanorods electrodes in photovoltaic cells, we found that the photocurrent was dramatically enhanced, comparing with those of bare TiO2 nanorods and CdS films electrodes. Moreover, TiO2@CdS core–shell nanorods film electrode showed better cell performance than CdS nanoparticles deposited TiO2 nanoparticles (P25) film electrode. A photocurrent of 1.31 mA/cm2, a fill factor of 0.43, an open circuit photovoltage of 0.44 V, and a conversion efficiency of 0.8% were obtained under an illumination of 32 mW/cm2, when the CdS nanoparticles deposited on TiO2 nanorods film for about 20 min. The maximum quantum efficiency of 5.0% was obtained at an incident wavelength of 500 nm. We believe that TiO2@CdS core–shell heterostructured nanorods are excellent candidates for studying some fundamental aspects on charge separation and transfer in the fields of photovoltaic cells and photocatalysis. 相似文献
Nanocomposite ZnO–Ag thin film containing nano-sized Ag particles have been grown on glass substrate by spin-coating technique
using zinc acetate dihydrate as starting precursor in 2-propanol as solvent and monoethanolamine as stabilizer. Silver nanoparticles
were added in the ZnO sol using silver nitrate dissolved in ethanol-acetonitrile. Their structural, electrical, crystalline
size and optical properties were investigated as a function of preheating, annealing temperature and silver content. The results
indicated that the crystalline phase was increased with increase of annealing temperature up to 550 °C at optimum preheating
temperature of 275 °C. Thermal gravimetric differential thermal analysis results indicated that the decomposition of pure
ZnO and nanocomposite ZnO–Ag precursors occurred at 225 and 234 °C, respectively with formation of ZnO wurtzite crystals.
The scanning electron microscopy and atomic force microscopy revealed that the surface structure (the porosity and grain size)
of the ZnO–Ag thin film (the film thickness is about 379 nm) was changed compared to pure ZnO thin film. The result of transmission
electron microscopy showed that Ag particles were about 5 nm and ZnO particles 58 nm with uniform silver nanoclusters. Optical
absorption results indicated that optical absorption of ZnO–Ag thin films decreased with increase of annealing temperature.
Nanocomposite ZnO–Ag thin films with [Ag] = 0.068 M and [Ag] = 0.110 M showed an intense absorption band, whose maximum signals
appear at 430 nm which is not present in pure ZnO thin films. The result of X-ray photoelectron spectroscopy revealed that
the binding energy of Ag 3d5/2 for ZnO–Ag shifts remarkably to the lower binding energy compared to the pure metallic Ag due to the interaction between
Ag and ZnO. 相似文献
In this study, it was aimed to increase the piezoelectric and pyroelectric properties of electrospun polyvinylidene fluoride (PVDF) nanofibers simultaneously by using specific nanofillers. Graphene oxide (GO), graphene, and halloysite nanotubes with different concentrations (0, 0.05, 0.4, and 1.6% wt/wt) were combined with PVDF solution and were fabricated in the form of nanofibers through electrospinning. Pyroelectric properties of samples were measured by submerging sealed samples in hot water (360°K) and ice (270°K). The piezoelectric properties of the samples were evaluated through bending tests. The microstructural, mechanical, and thermal properties of the electrospun PVDF nanocomposite were investigated using scanning electron microscope, Instron instrument, and thermogravimetric analysis, respectively. To further support the experimental observations for generating electric voltage in the bended nanogenerator, the PVDF nanogenerator (PNG) was also modeled by a finite element analysis based on the theory of linear piezoelectricity using COMSOL Multiphysics simulation software. Experimental results showed that adding nanofillers could improve the piezoelectric and pyroelectric properties of all samples, associated with the increment of β‐phase in the nanofibers. It was concluded that adding nanofillers could increase pyroelectricity about 50% more than piezoelectricity in pristine PVDF nanofiber web. The PNG containing 1.6 wt% GO showed the highest efficiency in terms of piezoelectricity and pyroelectricity. In addition, the results showed that the ratio of piezoelectric to pyroelectric coefficients was constant (~1.5) and it was independent of the nanofiller type and content. The effect of external force and vibration frequency on the output voltage was also investigated. Increasing the compressive force and vibration frequency caused a greater output voltage. Finally, the fabricated nanogenerator was integrated on insole and elbow to investigate its energy harvesting capabilities from body movement. 相似文献