Ceria/ PVDF/PVDF-HFP Nanocomposite: Designing, Characterization, Optical, Piezo- and Pyroelectric Properties for Energy Storage Systems A. Habib, T. Fahmy, A. Almalki, M. M. Metwally Journal of Inorganic and Organometallic Polymers and Materials, 2025 Poly vinylidene fluoride (PVDF) is blended with poly (vinylidene fluoride-co-hexafluoro propylene) (PVDF-HFP) via solution-casting technique. Herein, various concentrations of ex-situ synthetic ceria nanoparticles (CeO2NPs) were incorporated within a (50/50 wt% PVDF/PVDF-HFP) polymeric blend (PB). The prepared ceria nanocomposites were characterized by X- ray diffraction (XRD), Scanning electron microscope (SEM), Fourier transformed infrared (ATR-FTIR) and UV/Vis analysis. XRD and FTIR analysis confirmed that the crystalline electroactive β-phase in the PVDF and PVDF-HFP is enhanced after blending and doping with CeO2NPs. UV/Vis analysis showed that both direct and indirect band gaps for nanocomposites films are reduced to be about 3.37 and 3.2 eV, respectively. Thermally stimulated depolarization current (TSDC) measurement of the different relaxation phases with polarization in the corona discharge field for different prepared samples had been obtained. TSDC results of the main β-relaxation peak show an enhancement of the relaxation time (τ) and decrease in activation energy (Ea), which is related to higher regularity of the system structure. The piezo- and pyroelectric activity of the various prepared samples were investigated. Pyroelectric coefficient enhanced to be about ≈ 68.5 µC/m2K for 20wt.% CeO2/PB. The high piezoelectric coefficient d33 obtained for 20wt.% CeO2/PB was about 37.2 pC/N. This innovative flexible piezoelectric structure emerges as a strongly favorable candidate that can be applied as intelligent stress-responsive materials utilized in various energies harvesting piezoelectric technologies.
Investigation and optimization of the piezoelectric nanocomposite ZnO/PVVH/P(VDF-TrFE) for energy harvesting applications A. Sarhan, A. Hassan, M. I. Abdelhamid, T. Fahmy, A. Habib Scientific Reports, 2025 30/70 wt.% poly (vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) (PVVH) / poly (vinylidene fluoride-co-trifluoroethylene) P(VDF-TrFE) polymer blend (PB) are prepared and doped with various content of Zinc oxide nanoparticle (ZnO NPs) using casting technique. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM), UV–Vis and Thermogravimetric analysis (TGA) are used for structural, optical and thermal properties investigation. XRD results revealed that the crystallinity degree of PB is enhanced from 83.8 to 92.3% upon increasing the ZnO NPs. FTIR analysis showed a shift in position of some characteristic bands, confirming the complexation between ZnO NPs and functional groups of PB. UV–Vis analysis showed that both direct and indirect energy gaps (E dg /E ig ) are reduced from (4.08/2.34) for PB to (3.65/1.99) eV for 1.25 wt% ZnO/PB nanocomposite. Thermally stimulated depolarization current (TSDC) measurements demonstrated that the phase transition from ferroelectric to paraelectric phase occurred at 343 K for PB and increased to 350 K after embedding ZnO NPs. Thermal sampling (TS) technique is applied and thermodynamic parameters are estimated. Piezoelectric coefficient (d33) is optimized from 12.8 pC/N for PB sample to 23.7 pC/N for 1wt.% ZnO/PB nanocomposite at 6.24 × 105 Pa. Our results give a prediction for new piezoelectric material design capable for various energy harvesting applications.
Optical, AC conductivity and antibacterial activity enhancement of chitosan-silver nanocomposites for optoelectronic and biomedical applications A Sarhan, T Fahmy, A Habib Physica Scripta, 2024 This study is aimed to prepare and investigate the optical, electrical and antibacterial activity of the environmentally friendly (green) chitosan (Cs)/silver nanocomposites. TEM demonstrated that AgNPs have a spherical shape with particle size ranged from 3 nm to 25 nm. UV analysis spectra of Cs and Cs/Ag nanocomposites showed that, increasing the content of AgNPs led to a noticeable increase in the values of Urbach energy (E U ) and a dramatic decrease in both the indirect (E ig ) and direct (E dg ) optical bandgap energies. It is found that (E ig ) and (E dg ) are decreased from (4.72/5.31 eV) to (2.47/4.19 eV). The formation of the AgNPs is verified by the existence of surface plasmon resonance (SPR) peak at ∼ (421–450) nm. Wemple-DiDomenico and Sellmeier oscillator models are employed and displayed a clear enrichment in the dispersion energy (E d ) and oscillator energy (E 0) as well as the linear and nonlinear optical parameters of Cs. It is observed that the linear (χ(1)) and nonlinear (χ(3) and n2) parameters are enhanced from 0.083, 0.868 × 10−14 and 1.584 × 10−12 to 0.153, 9.762 × 10−14 and 4.088 × 10−12. The novel results in our study nominate Cs/Ag nanocomposites for applications in linear/nonlinear optical devices. AC conductivity behavior of Cs and Cs/Ag nanocomposites is analyzed based on Jonscher’s law and the analysis showed that the overlapping large polaron tunneling (OLPT) is the dominant conduction mechanism for our samples. It is clear that the values of dielectric constant (ε′) of Cs and Cs/Ag nanocomposites are higher confirming the presence of interface polarization (IP) relaxation. Moreover, it is found that the antibacterial activity of Cs against Gram-negative (P. aeruginosa) and Gram-positive (B. thuringiensis) bacteria is found to be enhanced with increasing the content of Ag NPs. These results suggested that Cs/Ag nanocomposites will be good source for preparing bio-nanocomposites for use in many biomedical and industrial applications.
Efficient single-crystal 4-N,N-dimethylamino-4-N-methyl-stilbazolium tosylate (DAST) on the optical, piezoelectric coefficient and structure of P(VDF-HFP) copolymer for energy conversion systems A. Habib, M. M. Metwally, T. Fahmy Polymer Bulletin, 2024 Poly(vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP) doped with 4-N,N-dimethylamino-4-N-methyl-stilbazolium tosylate (DAST) composites with various concentrations of DAST dye is prepared using the casting method. The crystal structure and optical properties of the pure and P(VDF-HFP)/DAST composites with various contents of DAST dye are investigated using various techniques such as UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and polarized optical microscopy (POM). The analysis of XRD data and FTIR spectra revealed that the β-fraction has been improved in the composite samples with increasing the content of DAST dye. Analysis of UV spectra displayed that the optical band gap of P(VDF-HFP) pure copolymer is 5.41 eV and has been reduced to be 3.75 eV for P(VDF-HFP)/10 wt% DAST that will be suitable for efficient systems of energy conversion and multijunction-based layer solar cells. Also, it is found that the nonlinear and linear optical parameters of the composite samples are DAST dye-dependent. Thermally stimulated depolarization current (TSDC) technique has been applied to investigate the dipolar and space charge relaxations of the composites. Moreover, it is observed that the pyroelectricity and piezoelectricity are enhanced with increasing the content of DAST dye. The highest content of the DAST dye showed maximum values of the pyroelectric and the piezoelectric coefficients of ~ 4 × 10–5 C/m2 K and ~ 34 pC/N at stress of 6.27 × 105 Pa, respectively. Our results of the polymer/dye composites give an opportunity of a promising material for flexible piezoelectricity devices used in many potential applications and energy harvesting systems.
Investigation of piezoelectric effect and thermally stimulated depolarization current of poly (vinyl chloride–co-vinyl acetate–co-2-hydroxypropyl acrylate)/poly (vinylidene fluoride-trifluoroethylene) polymer blend A. Hassan, A. Habib, M. I. Abdelhamid, T. Fahmy, A. Sarhan Ferroelectrics, 2023 DSC measurements revealed that the ferroelectric-paraelectric (F-P) transition point of PVDF-TrFE has been affected after blending with PVVH. XRD pattern and FTIR spectra of PVVH, PVDF-TrFE, and their polyblend samples are analyzed to investigate the effect of PVVH on the enhancement of crystallinity and β-fraction of PVD-TrFE. The piezoelectric coefficient (d 33) of PVVH/PVDF-TrFE polymer blend has been investigated under different parameters, such as the temperature, applied stress, and composition. It is found that the value of d 33 has been improved either with increasing temperature or increasing applied pressure for all samples. The maximum values of d33 at 0.62 MPa and 353 K are 1.01, 9.93, and 12.84 PC/N for pure PVVH, PVDF-TrFE, and 30/70 PVVH/PVDF-TrFE, respectively. TSDC of pure PVVH, PVDF-TrFE, and their polyblend samples has been studied in a wide range of temperatures at different poling electric fields. The results revealed that TSDC of pure PVVH is characterized by a dipolar relaxation peak centered at 351 K, whereas, pure PVDF-TrFE showed two peaks at 327 K, and the other is observed in the temperature range from 358 to 371 K. TS technique has been applied for decomposing TSDC spectra of all samples to its elementary peaks. It was verified that the compensation effect is operated for all samples and all thermodynamic parameters, such as ΔS, ΔH, and ΔG were calculated from the relaxation map analysis (RMA).
Enhancement of optical and piezoelectric properties of P(Vinylidene fluoride-hexafluoropropylene)/N,N-Dimethyl-4-nitro-4-Stilbenamine composites for optoelectronic applications A. Habib, M. Metwally, T. Fahmy, A. Sarhan Polymer Plastics Technology and Materials, 2022 XRD, FTIR, optical morphology, and UV spectroscopy are used to investigate (PVDF-HFP)/DANS composites. Analysis of XRD and FTIR revealed that β-phase of (PVDF-HFP) is enhanced. UV analysis revealed that, indirect and direct optical bandgap values were decreased from 4.01 to 1.32 eV and from 5.41 to 3.68 eV of pure and dye doped composite samples. Linear and nonlinear optical parameters values are calculated. The piezoelectric properties of (PVDF-HFP)/DANS composite samples have been investigated and the high piezoelectric coefficient value of composite samples (d33 ≈ 44 PC/N) makes us consider these composites as one of the most promising piezoelectric materials.
Upgrading the silicon IBC to the 40 % efficiency Amit Kumar Gupta, Vaibhav Pawar, Madhuwanti S. Joshi, Vivek Agarwal, Deepak Chandran 2017 IEEE 44th Photovoltaic Specialist Conference Pvsc 2017, 2017 Frequent power cuts necessitate the use of battery fed inverters in many homes and small industries in countries like India. Due to several charge and discharge cycles, the batteries have a typical life of 3 - 4 years. In this paper, a solar PV based retrofit solution is proposed which can be used along with these inverters. This solution uses a bi-directional DC to DC converter which charges and discharges the battery in the presence and absence of solar radiation respectively. The converter has been implemented using a simple add-on circuit with the main battery inverter. The proposed solution has the potential of providing high-quality power, grid connectivity, energy saving and enhancing the battery life. An analysis showing the effective energy saving using the proposed scheme has been presented. Simulations and experimental results have been obtained, and some representative results are included.
Upgrading the silicon IBC to the 40% efficiency Juan Carlos Jimeno, Jose Ruben Gutierrez, Vanesa Fano, Carlos del Canizo, Ahmed Habib, et al. Conference Record of the IEEE Photovoltaic Specialists Conference, 2016
