We fabricated ferroelectric films of the organic molecular diisopropylammonium chloride (DIPAC) using the dip-coating technique and characterized their properties using various methods. ...Fourier-transform infrared, scanning electron microscopy, and X-ray diffraction analysis revealed the structural features of the films. We also performed ab-initio calculations to investigate the electronic and polar properties of the DIPAC crystal, which were found to be consistent with the experimental results. In particular, the optical band gap of the DIPAC crystal was estimated to be around 4.5 eV from the band structure total density-of-states obtained by HSE06 hybrid functional methods, in good agreement with the value derived from the Tauc plot analysis (4.05 ± 0.16 eV). The films displayed an island-like morphology on the surface and showed increasing electrical conductivity with temperature, with a calculated thermal activation energy of 2.24 ± 0.03 eV. Our findings suggest that DIPAC films could be a promising alternative to lead-based perovskites for various applications such as piezoelectric devices, optoelectronics, sensors, data storage, and microelectromechanical systems.
Metal oxide nanoparticles (MONPs) (ZnO, TiO
2
, SiO
2
, and CuO NPs) were synthesized with an average size of around 50 nm. The synthesized MONPs were incorporated into Poly(methyl methacrylate) ...(PMMA) matrix deposited on glass substrate led to form PMMA/MONPs nanocomposite films. Fourier-Transform Infrared (FTIR) spectroscopy was employed to investigate the vibrational bands of pure PMMA and the incorporated PMMA/MONPs nanocomposite films. SEM micrographs showed the amorphous morphology of PMMA/MONPs nanocomposite films indicating the excellent dispersion of the MONPs on the surface. PMMA and PMMA/MONPs were exposed to the UV light for a period of 1, 3, and 5 min to investigate the impact on their refractive index (
n
). The UV-light exposure led to cause an increase in the refractive index of the PMMA in the visible region and decrease in the UV region and the opposite way around in the PMMA/MONPs nanocomposite films. Applying Maxwell–Garnett and Bruggeman's effective medium approximation models to investigate the distribution of the MONPs in the PMMA matrix shows a transfer from continuous aggregated nanoparticles to spherical or ellipsoidal distribution.
In this work, we reported a new insight on the kinetics of photoisomerization and time evolution of hybrid thin films considering the azo-dye methyl red (MR) incorporated with graphene accommodated ...in polyethylene oxide (PEO). The kinetics of photoisomerization and time-evolution of hybrid thin films were investigated using UV-Vis s and FTIR spectroscopies, as well as appropriate models developed with new analytical methods. The existence of azo-dye MR in the complex is crucial for the resource action of the
cycles through UV-illumination Visible-illumination relaxations. The results of the UV-Vis and the FTIR investigations prove the cyclical
...
.
This study introduces a novel nanocomposite coating composed of PANI/CeO2 nanocomposite films, aimed at addressing corrosion protection needs. Analysis through FTIR spectra and XRD patterns confirms ...the successful formation of the nanocomposite films. Notably, the PANI/CeO2 nanocomposite films exhibit a hydrophilic nature. The bandgap energy of the PANI composite film is measured to be 3.74 eV, while the introduction of CeO2 NPs into the PANI matrix reduces the bandgap energy to 3.67 eV. Furthermore, the electrical conductivity of the PANI composite film is observed to be 0.40 S·cm−1, with the incorporation of CeO2 NPs leading to an increase in electrical conductivity to 1.07 S·cm−1. To evaluate its efficacy, electrochemical measurements were conducted to assess the corrosion protection performance. Results indicate a high protection efficiency of 92.25% for the PANI/CeO2 nanocomposite film.
Four different ZnO nanostructures, namely nanoparticles, nanorods, nanoribbons, and nanoshuttles, were synthesized by controlling the pH levels, the chemical compositions, and the conditions of the ...process. Different ZnO nanostructures' structural, wettability, optical, and electrical properties depend on the morphology and particle size. In particular, X-ray diffraction patterns verify that lattice constants, crystallite size, microstrain, and other related structural parameters are affected by the surface morphology and the particle size. In addition, ZnO nanoparticles have hydrophilic nature, while the other nanostructures have hydrophobic nature. For example, the value of the optical bandgap energy for ZnO nanoparticles, ZnO nanorods, ZnO nanoribbons, and ZnO nanoshuttles is 3.30, 3.33, 3.39, and 3.36 eV, respectively, which is in excellent agreement with standard ZnO thin films bandgap energy values. Furthermore, ZnO nanorods have higher electrical conductivity than other nanostructures, while ZnO nanoshuttles have the lowest electrical conductivity. The grain boundaries and the semiconducting nature influence the electrical conductivity of ZnO nanostructures. Finally, the boundaries create various potential barriers to the transportation of electrons in the medium.
Graphical abstract
The scarce negative Poisson’s ratio (NPR) in a two-dimensional (2D) material is an exceptional auxetic property that offers an opportunity to develop nanoscale futuristic multi-functional devices and ...has been drawing extensive research interest. Inspired by the buckled pentagonal iso-structures that often expose NPR, we employ state-of-the-art first-principles density functional theory calculations and analyses to predict a new 2D metallic ternary auxetic penta-phosphorus boron nitride (p-PBN) with a high value of NPR. The new p-PBN is stable structurally, mechanically, and dynamically and sustainable at room temperature, with experimental feasibility. The short and strong quasi sp3-hybridized B–N bond and unique bond variation and geometrical reconstruction with an applied strain allow p-PBN to inherit a high value of NPR (−0.236) along the (010) direction, the highest among any other ternary penta iso-structures reported to date. Despite having a small elastic strength, the highly asymmetric Young’s modulus and Poisson’s ratio along the (100) and (010) directions indicate large anisotropic mechanics, which are crucial for potential applications in nanomechanics and nanoauxetics.
Elastic stiffness moduli were studied using dispersion-corrected density functional theory. The elastic stiffness moduli of
α
-DIPAB molecular crystals are found to be strongly anisotropic, with ...exceptionally high values of ~55 GPa. The magnitude of elastic stiffness modulus is strongly correlated with the relative orientation between the underlying hydrogen-bonding networks of DIPA molecules (“stitched” together by Br ions). These values of elastic stiffness modulus are remarkably high and suggest the design of hydrogen bond networks as a route for rational design of ultra-stiff molecular solids. Furthermore, Young’s modulus of
α
-DIPAB was found to attain extremely large value of as large as 50 GPa along certain crystallographic directions, while Br-deficient DIPAB has reduced Young’s modulus ( ~18 GPa). Anisotropy of Young’s modulus in
α
-DIPAB is very large with values below 40% of its maximum along specific spatial directions (and even lower in Br-deficient crystals).
α
-DIPAB and Br-deficient DIPAB show very different directionality of Young’s modulus due to the change in H-Br bond network upon Br deficiency. Additionally, Poisson’s ratio is strongly anisotropic as well with values ranging between a maximum of 0.4 for certain crystallographic directions and about 0.25 for other directions indicating the directionality of bonding in
α
-DIPAB. DIPAB systems are brittle based on the ratio between bulk and sheer elastic constants. Thus, DIPAB should be used as an element of composite materials to be used in thin-film flexible electronic application.
Graphical abstract
Summary
The structural, electronic, optical, and mechanical properties of XH2 (XCa, Sr, and Ba) earth hydrides) are obtained. Modified Becke‐Johnson (mBJ) exchange potential with a proper choice of ...basic parameters is used to calculate the electronic band‐structure, density of states, and optical properties. Strikingly, an excellent agreement between calculations and experiment is obtained. Under ambient conditions, XH2 (XCa, Sr, and Ba) are found to be structurally stable in the orthorhombic (PbCl2‐type) structure. The calculated structural parameters, such as the lattice constant, bulk modulus are investigated. Total energy minimization indicates that examined alkaline hydrides undertake a structural phase transition from the orthorhombic (PbCl2‐type) to hexagonal (Ni2In‐type) phase and the transition pressures were calculated. The chemical bonding of these alkaline earth hydrides is delineated using ab initio calculation. Investigation of the electronic density of states reveals that these hydrides are insulators. Furthermore, optical parameters such as, dielectric function, reflectivity, and absorption coefficients as functions of the wavelength of incident light are computed and analyzed. Remarkably, XH2 (XCa, Sr, and Ba) are found to exhibit strong optical anisotropy. In addition, elastic constants of the single‐crystal and polycrystalline forms of the investigated hydrides are numerically estimated and interpreted. The Voigt‐Reuss‐Hill (VRH) approximation is used to estimate the elastic constants of a surfaced polycrystalline hydrides in terms of its crystallographic texture and the elastic constants of the constituting single crystals under high pressure. The calculated optical and mechanical properties are in good agreement with previous theoretical and experimental studies.
There is very low asymmetry in bandgap determined from the dielectric function of the materials in cotunnite structure, while it exhibits a large asymmetry in hexagonal (Ni2In) structure. The symmetry change upon the phase transition is detectable by optical absorption, and other optical methods such as Raman. We used an mBJ functional that provides advantages in description of the bandgap and the optical properties of insulating materials over the approximations such as GGA and LDA, and sufficiently different from the hybrid functional implementations.
The profiles of food products are one interesting link that adds a new functional component. Cookies became one of the remarkable foods as a result of their simple preparation, a protracted period, ...and a sensible acceptance by the population. The effects of sonication on physical and sensory characteristics of cookies to be enhanced were studied. The results showed that cookies prepared with 5 and 10% replacement of sonicated whey protein had significant differences in sensory evaluation especially crumb, but there were no significant differences in the physical characteristics, so we can conclude that sonication will improve sensory properties of cookies. Also, we can conclude that biscuit samples supplemented with 5 or 10% WPC were nutrient-rich. The results of the sensory evaluation showed that the cookie samples supplemented with 5% WPC performed better in most of the characteristics but decreased with an increase in the WPC level. The texture properties of the cookie samples indicated that the control cookies with WPC-supplemented cookies showed no significant differences in most studied properties. It can be concluded that the addition of sonicated whey protein enhanced the physiochemical and sensory properties of cookies.
We report the synthesis and characterization of pure ZnO, pure CeO2, and ZnO:CeO2 mixed oxide thin films dip-coated on glass substrates using a sol-gel technique. The structural properties of ...as-prepared thin film are investigated using the XRD technique. In particular, pure ZnO thin film is found to exhibit a hexagonal structure, while pure CeO2 thin film is found to exhibit a fluorite cubic structure. The diffraction patterns also show the formation of mixed oxide materials containing well-dispersed phases of semi-crystalline nature from both constituent oxides. Furthermore, optical properties of thin films are investigated by performing UV–Vis spectrophotometer measurements. In the visible region, transmittance of all investigated thin films attains values as high as 85%. Moreover, refractive index of pure ZnO film was found to exhibit values ranging between 1.57 and 1.85 while for CeO2 thin film, it exhibits values ranging between 1.73 and 2.25 as the wavelength of incident light decreases from 700 nm to 400 nm. Remarkably, refractive index of ZnO:CeO2 mixed oxide-thin films are tuned by controlling the concentration of CeO2 properly. Mixed oxide-thin films of controllable refractive indices constitute an important class of smart functional materials. We have also investigated the optoelectronic and dispersion properties of ZnO:CeO2 mixed oxide-thin films by employing well-established classical models. The melodramatic boost of optical and optoelectronic properties of ZnO:CeO2 mixed oxide thin films establish a strong ground to modify these properties in a skillful manner enabling their use as key potential candidates for the fabrication of scaled optoelectronic devices and thin film transistors.
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