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In this study, the effects of illumination on the electronic and optoelectronic properties of Al/hydroxymethyl functionalized Zn(II)Pc/p-Si/Al photonic device have been investigated under dark and various lighting conditions. The diode's electronic parameters have been extracted from the current–voltage characteristics. It is observed that the dark current value increases when the light is illuminated on the device, and thus, the photocurrent is formed, and this result has shown that the studied device exhibits a photoconductive behavior. The photoresponse properties of the fabricated device have been examined by transient photocurrent measurements under 100 mW/cm2 illumination, and they have also been analyzed using photocapacitance and photoconductivity measurements at different frequencies (100 kHz, 500 kHz, and 1 MHz). However, the capacitance data that may occur between the poles of the produced device have also been investigated, and it is thought that the device can also be developed as a capacitor. These results confirm that the hydroxymethyl functionalized Zn(II)Pc and p-silicon semiconductor-based device can be used particularly in electro-optic and photonic applications. [ABSTRACT FROM AUTHOR]

Organic semiconductors have gained substantial interest as active materials in electronic devices due to their advantages over conventional semiconductors. We first designed four Schiff base compounds, then the effect of electron donor/acceptor groups (methyl/nitro) was studied on the compounds' electronic and transport nature. The absorption spectra (λabs) were computed by time-dependent DFT at TD-B3LYP/6-31+G** level. The effect of different solvents (ethanol, DMF, DMSO, and acetone) was investigated on the λabs. The substitution of the -NO2 group to the furan moiety at the 5th position in Compound 3 leads to a red-shift in the absorption spectrum. A smaller hole reorganization energy value in Compound 3 would be beneficial to get the hole's intrinsic mobility. In contrast, a reduced-electron reorganization energy value of Compound 4 than hole may result in enhanced electron charge transfer capabilities. The reorganization energies of compounds 1 and 2 exposed balanced hole/electron transport probability. The optical, electronic, and charge transport properties at the molecular level indicate that Compound 3 is suitable for organic electronic device applications. [ABSTRACT FROM AUTHOR]

Carboxylic acid supramolecular synthon exhibited dimer or catemer motifs in the crystal lattice depend on the substituent and other functional groups present in the structure. In general, presence of other competing functional groups produced catemer motifs, whereas unsubstituted acids showed dimer. In this manuscript, we have synthesized a new aryl ether amine-based Schiff base with carboxylic acid functionality (1) and demonstrated polymorphic structure via catemer (1a) and dimer (1 b) motifs in the solid state. In both the structure, carboxylic acid group adopted different orientation in the crystal lattice. The different H-bonding lead to modulation of optical properties that was further supported highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) calculation. Further the stability calculation indicates that dimer (1 b) structure was more stable by 8.54 kcal/mole relative to catemer (1a) motifs. Further, the supramolecular interactions in catemer (1a) and dimer (1 b) motifs was studied by Hirshfeld surface and fingerprint plots to gain insight and compare the different functional groups contribution for intermolecular interactions in the polymorphic crystals which clearly showed different intermolecular interactions in polymorphs. [ABSTRACT FROM AUTHOR]

In our research described here nanocomposites containing a newly synthesized methacrylate polymer, poly 2-(4-fluorophenyl)-2-oxoethyl-2-methylprop-2-enoate (PFPAMA) and ZnO nanoparticles in various mass ratios (1, 3 and 5 w %) were synthesized using the hydrothermal method. The synthesized nanocomposites were characterized by Fourier-transform infrared spectroscopy (FTIR), Hydrogen-1 nuclear magnetic resonance (1H-NMR) and X-ray diffraction (XRD) techniques. Both real and imaginary components of the complex dielectric permittivity of pure PFPAMA and the three different PFPAMA/ZnO nanocomposites were measured as a function of frequency. The dielectric study revealed that the ZnO nanoparticles improved the dielectric properties of pure PFPAMA. The variation of electrical conductivity, with frequency showed that the σ value increased linearly with increasing ZnO content. The frequency dependence of the conductivity suggested that the conduction occurs via a barrier hopping process. The obtained results suggest that the ZnO-doped, poly-2-(4-fluorophenyl)-2-oxoethyl-2-methylprop-2-enoate nanocomposites can be used as a dielectric material in dielectric device applications. [ABSTRACT FROM AUTHOR]

In this study, the impact on the dielectric properties of 8CB with the dispersion of TiO2, ZnO, and methylene blue (0% to 5%) is examined. Employing capacitance–voltage (C–V) measurements across frequencies ranging from 10 kHz to 2 MHz, we explore the combined effects of dispersed photoactive nanoparticles and mono/polymeric materials like MB. Our investigation provides novel insights into the nuanced variations induced by transition-metal oxide loaded 8CB, highlighting the role of their oxidation states, and elucidates the influence of larger photoactive monomers on 8CB's dielectric polarizability. The study found that the dielectric anisotropy was strongly influenced by frequency and doping, changing sign at a critical frequency. Our work represents the first comparative analysis incorporating these oxides alongside photoactive materials like MB. • Explores effect of 0 to 5% ZnO, TiO 2 and MB doping on the dielectric anisotropy of 8CB liquid crystal. • Capacitance–voltage measurements of dielectric anisotropy over 200 kHz to 2 MHz. • Dielectric anisotropy changes sign from positive to negative for all dopants, highest for MB. • Dopant introduces optical properties and enhances dielectric permittivity of 8CB. [ABSTRACT FROM AUTHOR]

Due to the future uses of solar energy in different areas, such as the oxidation of fossil fuel-based contaminants, the reduction of carbon dioxide, heterogeneous photocatalysis, and the generation of inexhaustible and renewable hydrogen gas exploits semiconductors. As a metal free photocatalyst, graphitic carbon nitride (g-C 3 N 4) is classified to solve these energy hazards and ecological difficulties owing to its excellent electronic structure with band energy of about 2.7 eV, robust photochemical stability, and better light-harvesting efficiency. However, its photocatalytic performance is still insufficient due to a minor surface area and poor conductivity. Therefore, heterojunction formation by combining it with a giant band gap material is a potential approach to reestablish polarization in its distinctive band structure, increase its light absorption capacity and enhance its surface area. In this regard, various synthesis techniques have been applied so far to integrate g-C 3 N 4 and other materials for boosting its photocatalytic activity. So far, metal oxide, sulfides, and ferrites are three crucial groups of materials that have been identified and defined to be used to synthesize g-C 3 N 4 dependent nanocomposites. As a result, in this review, we have compiled a list of the most recent g-C 3 N 4 nanocomposites with their applications in solar energy adaptation and pollution control. This study concludes an overview about the next steps to study the nanomaterials based g-C 3 N 4 composites and a range of additional insights to solve the present problems. • This review addresses the properties and structures of g-C 3 N 4 photocatalyst structure. • Pros and cons of their synthesis techniques. • The types of the g-C 3 N 4 -based nanocomposite are emphasized. • Approaches to improve the photocatalytic activity of g-C 3 N 4. • The most up-to-date photocatalytic applications were thoroughly discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Perovskite LaFeO 3 , spinel NiFe 2 O 4 and their composites were synthesized using the normal microemulsion process. • The degradation of methylene blue in the composite (92%) was significantly greater than that of lanthanum and nickel ferrite due to suitable band gap value. • Light-induced electron/hole recombination from the valence band to the conduction band may be impeded in the composite which is responsible for the higher activity of this material. • This inhibition in recombination of electrons/holes pair was also confirmed by the PL analysis. Most dyes are carcinogenic; thus, they must be removed from the water to save aquatic and human life. Among the various methods, the photocatalytic degradation of dyes is attracting much attention due to the easy strategy driven by the solar light. Herein, we report the fabrication of nickel ferrite (NiFO), lanthanum ferrite (LFO) and their composite are utilized as a light-driven catalyst for the deprivation of significant commercial dyes. The straightforward microemulsion method is used to produce both pure ferrite materials and their composite counterparts. The phases of the synthesized materials were verified through XRD analysis while scanning electron microscopy was employed to examine their morphology. The average crystallite size of the LFO, NiFO and their composite was 53, 62 and 42 nm, respectively. The elemental composition of the pristine and composite was confirmed by the energy dispersive spectroscopic analysis, indicating no other impurity in the materials. The optical properties are analyzed via UV visible and photoluminescence to measure the band gap value of 2.05, 1.73 and 1.9 eV for LFO, NiFO and their composite, respectively. It is observed that the LaFeO 3 /NiFe 2 O 4 has the highest photodegradation efficiency (92 %) as compared to the LFO (LaFeO 3) and NiFO (NiFe 2 O 4). The composite material also showed excellent reusability as well as good stability. It was also confirmed that OH radicals are the major contributor toward the dye degradation, as confirmed by the scavenger tests. The higher mineralization of methylene blue in the occurrence of composite as a catalyst may cause rapid charge transfers, as confirmed by EIS, and it may stop the recombination of electrons/hole pairs due to suitable band alignments. [ABSTRACT FROM AUTHOR]

GO-doped LaB 6 nanocomposite-based Al/p-Si/GO:LaB 6 /Al photodiodes were fabricated for the study. The electrical properties of the fabricated photodiodes were subjected to current-voltage and capacitance-voltage measurements. The ideality factors, barrier heights and series resistance values of photodiodes were calculated and compared using the Cheung-Cheung and Norde methods approaches. The lowest ideality factor values were calculated to be 4.75, 4.00 and 9.21 in the samples doped with GO at 1 %, 5 % and 10 %, respectively, and the highest barrier height values were calculated from the Norde function to be 0.75, 0.64 and 0.75 eV, respectively Additionally, the responsivity (R) and detectivity (D) values of the diodes were calculated. The R values of 1 %, 3 % and % 5 doped diodes were calculated as 2153, 6001 and 2042 mA/W at, 100 mW/cm2, respectively. The D* values of 1 %, 3 % and % 5 doped diodes are calculated as 1.38 × 1011, 3.85 × 1011 and 1.31 × 1011 Jones at 100 mW/cm2, respectively. The interface state (Nss) of 1 %, 3 % and % 5 doped diodes were calculated as 2 × 1013, 1.25 × 1013 and 1.06 × 1013eV−1 cm−2, at 100 mW/cm2, respectively. It can be concluded that the diodes produced in this study have potential for use in optoelectronic applications. [Display omitted] • GO-doped LaB 6 composite-based Al/p-Si/GO:LaB 6 /Al photodiodes were fabricated for the study. • Electrical parameters of photodiodes were calculated and compared using the Cheung-Cheung and Norde methods approaches. • Fabricated photodiodes were subjected to current-voltage and capacitance-voltage measurements. [ABSTRACT FROM AUTHOR]

Developing heterogeneous metal nanocatalysts is highly desirable since the catalyst can be easily separated and reused for several times. In this manuscript, we have immobilized gold nanoparticles (AuNPs) on the surface of mesoporous silica (SiO 2) using simple amino acid-based phenolic chelating molecules and utilized as highly reusable catalyst for nitroarene reduction. The synthesized nanocomposites (Au@SiO2-1 and Au@SiO2-2) have been unambiguously confirmed using powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR), high resolution-transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Interestingly, Au@SiO2-1 exhibited highly enhanced 4-nitrophenol reduction that was studied using absorption spectroscopy. Further catalytic activity of Au@SiO2-1 was also explored for 2-nitroaninline and 4-nitroaniline. The reusable studies demonstrated that the catalyst did not show significant change in the activity up to ten cycles. After catalytic reactions studies confirmed the strong attachment of AuNPs on the SiO2 matrix. Immobilization of AuNPs directly on the mesoporous SiO2 using L1/L2/MPTS organic surface functional molecule was performed. The integration of AuNPs on SiO2 matrix was confirmed using PXRD, FT-IR, HR-TEM and XPS analysis. Aromatic nitro to aromatic amine conversion catalytic studies showed good reusability and enhanced reduction activity for Au@SiO2-1. [ABSTRACT FROM AUTHOR]

Among the N‐containing heterocyclic compounds, quinazoline‐4‐(3H)‐one derivatives have been the center of attraction of medicinal and synthetic chemists due to their excellent versatility in biological activities that are witnessed by many approved drugs available in the market which contains quinazoline as main pharmacophore unit. This review mainly focuses the recent and current progresses in quinazoline derivatives as an acetylcholinesterase (AChE) and monoamine oxidase (MAO)‐B inhibitors. The review has leanings towards the molecular determinants and structure‐activity relationships (SAR) of quinazoline derivatives on AChE and MAO inhibitory potencies. [ABSTRACT FROM AUTHOR]

The vulcanization properties, physicochemical, dielectric, and electrical properties of natural rubber-based composites were investigated and compared. The composites contain 30–70 phr functional fillers having low (silicon dioxide (SiO2)) and high (titanium dioxide (TiO2)) dielectric constant values. The possibilities of using the composites as substrates in compact flexible antennas have been evaluated. Fillers are also characterized. It has been shown that they have a noticeable but different influence on all the properties of the composites studied. That is primarily due to the different structure and specific properties of SiO2 and TiO2, thereby determining the different "filler–filler" and "rubber–filler" interactions. The composite filled with TiO2 at 70 phr has a better capacity to act as a substrate in body area network antennas than the SiO2-filled composites. An antenna with such a substrate has features that meet all the requirements of the industrial, science, and medical spectrum. TiO2 composites do not change their resistance to pressure or deflection within certain limits, having a self-cleaning and antibacterial effect, which is also beneficial for their usage in antennas that are left on or near the human body. [ABSTRACT FROM AUTHOR]

We propose a new broadband flexible waterproof antenna suitable for Internet of Things applications. The antenna is comprised of three components: radiating elements fed by a 50-Ω coplanar waveguide transmission line and two layers from an elastomer composite (used as a substrate and top encapsulation) which completely covers the antenna's radiating elements to provide water and dust resistance. An antenna prototype is fabricated and tested. Experimental and numerical results show that the proposed antenna has broad bandwidth (|S11| ≤ −10 dB) over the frequency range of 0.83–2.52 GHz, high radiation efficiency of about 92% and good radiation patterns. The antenna was also immersed into water for 10 s, 10, 30 and 60 min, respectively and reflection coefficient magnitudes were measured, to verify its waterproof capability. The durability and flexibility tests were performed on the antenna prototype. Results show that there is no significant degradation in the antenna performance. [ABSTRACT FROM AUTHOR]

The photovoltaic properties of a monocrystalline silicon solar cell were investigated under dark and various illuminations and were modeled by MATLAB programs. According to AM1.5, the studied solar cell has an efficiency rate of 41–58.2% relative to industry standards. The electrical characteristics (capacitance, current–voltage, power-voltage, transient photovoltage, transient photocurrent, and impedance) of a silicon solar cell device were examined. Under complete darkness and light intensity of 100 mW/cm2, respectively, we have noticed that the light of the AM1.5 spectrum changes all PV-cell parameters such as short current, open circuit voltage, maximum power, maximum voltage, and power conversion efficiency. An electrical equivalent circuit (R1//C1 + R2//C2) was used by the Zview software to fit the experimental data of the Nyquist representations (-Z'' vs. Z'). By analyzing the peak of the conductance Gp versus frequency, the density of interface states and the interface trap time constant were calculated. By using MATLAB programs, we have modeled the current versus voltage and power versus voltage properties of equivalent solar cell circuits, ensuring a good agreement between the experimental and theoretical curves. [ABSTRACT FROM AUTHOR]

Zinc metal–organic frameworks (Zn-MOFs) of phthalic acid (ZnPA) and nitro-phthalic acid (ZnNPA) microcrystalline particles were fabricated and utilized for the removal of organic cationic dyes (crystal violet (CV), methylene blue (MB) and rhodamine B (RhB)) from water. PXRD studies confirmed the formation of crystalline materials, and BET indicated the mesoporous structure. HR-SEM studies showed the rod and plate morphologies for ZnPA and ZnNPA, respectively. ZnPA revealed low adsorption of dyes (CV, 20%) whereas ZnNPA showed significantly enhanced dye adsorption (CV, 99%). In particular, ZnNPA exhibited higher adsorption of CV (99%) and MB dye (83%) compared to RhB (54%). Nevertheless, ZnNPA could not be reused due to strong adsorption of dyes. Hence, a natural binder was introduced by dipping ZnNPA into tea extract, which also showed high adsorption of CV and MB dyes. Kinetics of adsorption exhibited best fitting with the pseudo-second-order model, indicating strong interactions between the dyes and adsorbent. Adsorption isotherm fitting suggested a good correlation coefficient (R2) with the Freundlich model, suggesting multi-layer adsorption. Interestingly, ZnNPA showed high adsorption of CV and MB dyes across the pH range between 3.0 and 11.0. The binder-introduced ZnNPA adsorbent was easily regenerated and demonstrated three cycles of reusability without significant change in the dye adsorption. Thus, the present work indicated the role of functional groups in the ligand and binder for improving the dye adsorption characteristics of MOFs. [ABSTRACT FROM AUTHOR]

This study investigates the fabrication and performance analysis of Al/CuO:LaB6/p-Si/Al diodes with CuO-doped LaB6 interlayer films of varying concentrations (1%, 5%, and 10%). Experimental evidence demonstrates the limitations of 0% CuO doping, as pure LaB6 lacks a significant barrier height, resulting in ohmic behavior unsuitable for intended applications. Through comprehensive analyses under varying illuminations (20–100 mW/cm2) and frequencies (10 kHz–1 MHz), the study reveals that controlling CuO doping in LaB6 significantly enhances the effective barrier height at the LaB6:CuO heterojunction, improving rectification properties. This enhancement enables the diode to be well-suited for high-speed photonic devices utilizing one-step photoemission. The findings contribute to the development of high-performance LaB6-based devices, advancing photonic technologies by emphasizing the advantages of CuO doping. • CuO alloying transforms metal-like LaB6 into a semiconductor. • CuO:LaB6 p-type films enhance barrier height, rectification, and response speed. • The Al/CuO:LaB6/p-Si/Al diodes are room temperature photovoltaic and photoconductive. • One-step photon emission process accounts for LaB6:CuO films interactions. • Devices have fast and excellent photoconductive and photovoltaic one-step photoemission. [ABSTRACT FROM AUTHOR]

SARS‐CoV‐2 coronavirus has been recognized the causative agent of the recent and ongoing pandemic. Effective and specific antiviral agents or vaccines are still missing, despite a large plethora of compounds have been proposed and tested worldwide. New compounds are requested urgently and virtual screening can offer fast and robust predictions to investigate. Moreover, natural compounds were shown to exert antiviral effects and can be endowed with limited side effects and wide availability. Our approach consisted in the validation of a docking protocol able to refine the most suitable candidates, within the 31000 natural compounds of the natural product activity and species source (NPASS) library, interacting with the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) spike glycoprotein. After the refinement process two natural compounds, castanospermine and karuquinone B, were shown to be the best‐in‐class derivatives in silico able to target an essential structure of the virus and to act in the early stage of infection. [ABSTRACT FROM AUTHOR]

Present investigation deals with an in depth study of three compounds including 4-(4-chlorophenyl)-8-methyl-2-oxo- 1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile (1), 4-(4-bromophenyl)-8-methyl-2-oxo-1,2,3,4,4a,5,6,7-octahydroquinoline-3- carbonitrile (2) and 8-methyl-2-oxo-4-(thiophen-2-yl)-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile (3) with respect to their structural, electronic, optical and charge transport properties. The ground and excited states geometries were optimized by density functional theory (DFT) and time dependent DFT, respectively. To rationalize the adopted methodology, the calculated geometrical parameters at ground state were compared with the experimental crystal structures. Several quantum chemical insights including the analysis of frontier molecular orbitals (FMOs), total/partial density of states (T/PDOS), molecular electrostatic potentials (MEP), local and global reactivity descriptors revealed that the studied compounds would be efficient multifunctional materials. The absorption wavelengths as well as their major transitions were thoroughly studied at TD-B3LYP/6-31G** level of theory. The smaller hole reorganization energies indicate that all these compounds might show better hole transport tendency. The anionic geometry relaxation of compound 2 is larger than the cationic form which leads to higher electron reorganization energy revealing the reduction of electron charge transport as compared to the hole. [ABSTRACT FROM AUTHOR]

The present work is involved in the computational and experimental studies of organic dyes and their applications as dye-sensitized solar cells (DSSCs). This comprised the study of three hydrazone-based sensitizers (E)-2-cyano-N′-((2-hydroxynaphthalen-1-yl)methylene)acetohydrazide (CHMA), (E)-2-cyano-N′-(4-(dimethylamino)benzylidene)acetohydrazide (CDBA), (E)-N′-(anthracen-9-ylmethylene)-2-cyanoacetohydrazide (AMCH) that have been prepared and confirmed by means of several analytical procedures like Fourier transform infrared, UV–visible and nuclear magnetic resonance techniques to investigate the best possible selection for DSSCs by computational and experimental techniques. The computational methods are applied to optimize the structures of prepared organic dyes via density functional theory (DFT) method at B3LYP/6-311G(p,d) level of theory. The time-dependent DFT (TD-B3LYP/6-311G**) was used with and without solvent to find out the absorption spectra and matched with the experimental data and the electro-optical and reorganization energies of prepared dyes were further investigated. The results revealed that the prepared dyes would be better sensitizers for DSSCs because of small highest-occupied molecular orbital–lowest-unoccupied molecular orbital energy gap. Moreover, on the basis of the above results, we fabricated the devices via the doctor blade method to study the photovoltaic performance with the prepared dyes (CHMA, CDBA and AMCH). The dye AMCH exhibited the maximum efficiency with commercial TiO2. [ABSTRACT FROM AUTHOR]

This paper presents comparative investigations on dual and ternary composites based on nitrile butadiene rubber. These composites were filled with carbon black and nickel powder at various ratios with each filler or with a combination of both. The focus of this study is on the electrical, mechanical and dynamic properties of the materials as influenced by the loading rate, applied pressure and bending degree have on the specific volume electrical resistivity. The investigations of the dynamic properties view the effect that the amount and chemical nature of the fillers have on the storage modulus and the tangent of the mechanical loss angle. It has been established that the specific characteristics of each of the fillers (particle size, specific surface, tendency to aggregate and agglomerate, interaction with the elastomeric matrix) have the greatest impact on composite properties. Scanning electron microscopy studies of the fillers and composites also confirm the results obtained. [ABSTRACT FROM AUTHOR]

In order to tune the optoelectronic and charge transfer properties of 4,6-di(thiophen-2-yl)pyrimidine (1), some new compounds were designed, i.e., 4,6-bis(benzo[b]thiophen-2-yl)pyrimidine (2), 4,6-bis(naphtho[2,3-b]thiophen-2-yl)pyrimidine (3), 4,6-bis(anthra[2,3-b]thiophen-2-yl)pyrimidine (4), 4,6-bis(tetraceno[2,3-b]thiophen-2-yl)pyrimidine (5) and 4,6-bis(pentaceno[2,3-b]thiophen-2-yl)pyrimidine (6). Compounds 2–6 were designed by assimilation of benzene, naphthalene, anthracene, tetracene and pentacene, respectively at both ends of compound 1. Integration of oligocene end cores reduces the energy gap resulting in a red shift in the absorption and fluorescence emission spectra. The legible intra-molecular charge transfer is significant from electron-rich moieties to the electron-deficient core (pyrimidine). The elongation of π -conjugation led to escalate the electron affinity, lower the ionization potential and hole reorganization energy. The hole reorganization energies of compounds 3–6 exposed that these materials would be effective hole transport contenders to be used in diverse semiconductor devices. [ABSTRACT FROM AUTHOR]

Wearable antennas exhibit numerous challenges in terms of design and optimization due to the specific environment in which they operate. Therefore, the design of such antennas is a non-trivial task, as multiple constraints have to be satisfied. We present an algorithm for design-and-optimization of flexible wearable antennas with high radiation efficiency and low specific absorption rate, that takes into account the dielectric loading of the human body. It provides a list of feasible antenna designs, not just a single solution, and identifies the optimal wearable antenna design. Numerical examples on the design and optimization of a wearable antenna (based on a dipole structure with a reflector) to demonstrate the validity and efficiency of the proposed algorithm are given. The optimal antenna design shows robust on-body performance and provides a suitable balance between small antenna size (antenna surface is 2214 mm²), high radiation efficiency (57.73%), and low value of the maximum 10 g average SAR (0.112 W/kg) on a homogeneous semisolid phantom. Finally, the optimal antenna design is fabricated. The antenna performance is studied under different conditions: on a homogeneous semisolid phantom, on a liquid phantom, on a three-layer semisolid phantom, on a human arm and in the free space. A good agreement between simulated and measured antenna performance is observed. [ABSTRACT FROM AUTHOR]

Abstract A simple hydrazine carboxamide derivative with intramolecular charge transfer and aggregation induced emission (AIE) properties have been designed and synthesized. The derivative (Probe 1) shows typical AIE characteristic emission in THF-water mixtures and emits yellowish orange color on reaching the water fraction 98%. The probe molecule show selective sensing response for Cu2+ ions via fluorescence turn-off mechanism in aqueous media over other metal ions. The emission changes towards Cu2+ ions that could be clearly observed by the naked eyes under 365 nm UV lamp promote the probe molecule as a promising candidate for practical utilization. Furthermore, from the fluorescence titration data, the detection limit for Cu2+ ions was found to be 0.44 μM. Graphical abstract Unlabelled Image Highlights • A simple caboxamide derivative displaying aggregation induced emission has been synthesized. • It can act as fluorescent probe for Cu2+ions. • The sensing ability of the derivative could be visualized using 365 nm UV lamp. [ABSTRACT FROM AUTHOR]

We developed a green, inexpensive and simple method for the synthesis of silver nanoparticles from the Opuntia Ficus (OF) Indica fruit juice. The synthesized AgNPs were used as sensor for the detection of toxic metal (Hg2+) using colorimetric technique as well as to investigate the antimicrobial activities against number of clinical isolates of human microbes. The synthesized AgNPs nanoparticles were characterized using UV-Vis spectroscopy, FTIR spectroscopy, scanning electron microscopy and EDX methods. The green synthesized AgNPs showed surface plasmon resonance absorption band at 441 nm, which confirm the formation of AgNPs that were also established by FTIR and EDX analyses. The colour of AgNPs changes from blood red to white in the presence of Hg2+ only, which can be differentiated and detected by the naked eye within few seconds without the prerequisite of surface amendment from other metals (Co, Ni, Fe, Mn, Pb, Zn, Cr). A good linear response (R2=0.97) was obtained towards Hg2+ ions in the concentration range of 10-3 to 10-8M. In addition, all growth of the tested microbial stains ceased in varied range. OFAg-2 had the highest inhibition effect followed by OFAg-1, while OF did not show any antimicrobial activities. Candida albican and Klebsiella pneumonia are the most susceptible microbes by OFAg-2 and OFAg-1 respectfully. Klebsiella oxytocam, Proteus mirabilis and Klebsiella oxytoca had the moderate susceptibility from OFAg-2 and OF, while Staphylococcus aureus was found to be the lowest susceptible microbes. Therefore, OFAg-2 and OFAg-1 probably could be promising pharmaceutical agents against many microbial strains. [ABSTRACT FROM AUTHOR]

In this paper, we have reported the green synthesis of silver nanoparticles (AgNPs) using silver nitrate and Ficus carica (fig) stem extract at room temperature. We have also explored the effect of volume of extract (1-3 ml) on the formation of AgNPs using various analytical techniques such as Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), and energy-dispersive X-ray analyzer (EDX). The formations of AgNPs were monitored by ultraviolet-visible spectrophotometer as well as from color change through the naked eye. The absorption peaks appear between 442 and 455 nm, confirming to surface plasmon resonance (SPR) of AgNPs. It is clear from the FTIR results that the biologically active compounds present in the extract act as capping and reducing agents for AgNPs creation. Electron microscopy results show that by increasing the concentration of extract, the morphology and size of AgNPs changed due to the presence of more phenolic group. The green synthesized AgNPs have been sequentially employed for the selective and sensitive detection of toxic metal ion (Hg2+) in aqueous medium and antimicrobial activity against all tested microbes including five gram negative and two gram positive. Furthermore, the brown color of green synthesized AgNPs turned into colorless with Hg2+ ion by naked eye response and the limit of detection was 1.06 µM. Figure (A) represents the UV-visible spectra of AgNPs with different concentrations of Hg2+ (0.1-10 µM) in aqueous solution and inset shows the variation of the absorbance of AgNPs solution as a function of Hg2+ ion concentration. Figure (B) represents the images of color variations of AgNPs with different concentrations of Hg2+ (10−1-10−7 M) in aqueous solution. [ABSTRACT FROM AUTHOR]

A novel pyrazolyl chromene derivative (Probe 1 ) displaying aggregation induced emission (AIE) properties that capable of sensing of multiple metal ions has been designed and synthesized. The multi analyte probe exhibits selective sensing for Cu 2+ and Ni 2+ ions via fluorescence turn-off mechanism and ratiometric selectivity for Hg 2+ ions in aqueous media. The extent of binding of the probe with sensitive metal ions has been demonstrated. The experimental results were further investigated by computational means by optimizing the ground state geometries of Probe 1 and its various metal complexes for Probe 1 -Ni, Probe 1 -Hg and Probe 1 -Cu using density functional theory (DFT) at B3LYP/6-31+g(d,p) (LANL2DZ) level. On the basis of binding energies, the stability of metal complexes has been studied. In Probe 1 -Ni and Probe 1 -Cu complexes, charge transfer has been observed from Probe 1 to metal ions revealing ligand to metal charge transfer (LMCT) while in Probe1-Hg complex LMCT as well as intra-molecular charge tranfer (ICT) within Probe 1 . [ABSTRACT FROM AUTHOR]

We propose ANN-based models to analyze and extract the internal parameters of a Schottky photodiode (SPD) without presenting them with any knowledge of the highly nonlinear thermionic emission (TE) expression of the device current. We train, evaluate and demonstrate the ML models on thirty-six private datasets from three previously published devices, which denote current responses under illumination and ambient temperature of graphene oxide (GO) doped p-Si Schottky barrier diodes (SBDs). The GO doping levels are 0%, 1%, 3%, 5%, and 10%. The illumination ranged from dark (0 mW/cm2) to 30 mW/cm2. The predictions are then made completely at the intensity of 60 mW/cm2. For each diode, some values of the barrier height (ϕ ), ideality factor (n), and series resistance ( R s ) independently calculated using the Cheung–Cheung method were included in the training dataset. The predictions are done at unspecified intensities on the model development data at 80 and 100 mW/cm2, and on external data at 5% and 20% GO doping which were not part of the development dataset. The ANN achieved a mean square error and mean absolute error score below 0.003 across all datasets. This demonstrates the effective learning capabilities of the ANN models in accurately capturing the photo responses of the photodiodes and accurately predicting the internal parameters of the Schottky Barrier Diodes (SBDs), all without relying on an inherent understanding of the thermionic emission (TE) equation for SBDs. The ANN models achieved high accuracy in this process. The proposed ML models can significantly reduce analysis time in device development cycles and can be applied to other datasets in various fields. [ABSTRACT FROM AUTHOR]

The present study spotlights the hybrid chalcone derivatives consisting of coumarin moieties conjugated systematically with different heterocyclic rings. The heterocyclic rings including bifuran, bicyclopentane, bipyrrole and bithiophenes groups are used to design compounds 1 , 2 , 3 and 4 , respectively. Different density functional theory (DFT) methods are used for optimization of designed compounds. The M06 functional shows reasonably good accuracy for calculations of geometrical and absorption spectra as compared with other methods and/or available experimental data. The calculated average third-order NLO polarizabilities ( γ ) for compounds 1 , 2 , 3 and 4 are found to be 526.22 × 10 −36 , 675.40 × 10 −36 , 939.58 × 10 −36 and 1109.30 × 10 −36 esu., respectively, at M06/6-311G** level of theory. The γ amplitudes of compounds 1 , 2 , 3 and 4 are reasonably enhanced, which are about 25, 27, 30 and 32 times larger to the γ amplitude of para nitroaniline (a prototype NLO molecule) at same M06/6-311G** level of theory. Furthermore, we highlight the structure-property relationship using TD-DFT calculations for absorption and emission spectra, frontier molecular orbitals and molecular electrostatic potential maps. Thus, the present study will evoke the interest of scientific community to develop the above title materials for efficient NLO applications. [ABSTRACT FROM AUTHOR]

We report a novel coumarin based optical chemosensor (Probe 1 ) for the selective and sensitive detection of Cu 2+ ions in aqueous medium. The addition of Cu 2+ ions to Probe 1 shows distinct color change from light yellow to pinkish red color under visible light with the sensing limit of 1.54 μM. Moreover, practical utility of Probe 1 as solid state optical sensor (test paper, TLC plates) for sensing Cu 2+ has been demonstrated by instantaneous “naked eye” response. [ABSTRACT FROM AUTHOR]

Organic molecules having extended π-conjugated moieties is useful for creating ‘dynamic’ functional materials by modulating the photophysical properties and molecular packing through non-covalent interactions. Herein, we report the photoluminescence properties of a luminogen, NBA, exhibiting aggregation-induced emission (AIE) characteristics, synthesized by Knoevenagel condensation reaction between 2-Hydroxy naphthaldehyde and malononitrile. NBA emits strongly upon aggregation and in solid state with large Stokes shift whereas it is non emissive in pure solvents. The aggregation induced emission behavior of the compound was carried out in DMSO (good solvent)-water mixture (poor solvent) with water fraction ( f w) ranging from 0% to 98%. The AIE property of the luminogen were further exploited for fabricating rewritable fluorescent paper substrates that found applications in security printing and data storage where the written images or letters stored on the filter paper are invisible under normal light. [ABSTRACT FROM AUTHOR]

Al/p-Si/BODIPY/Al diode was fabricated by forming BODIPY organic layer on p-Si having ohmic contact. The electrical and photoresponse properties of the prepared diode were investigated in detail. The current-voltage (I-V) measurements were performed under dark and various illumination intensities. It is observed that the photocurrent under illumination is higher than the dark current. The transient measurements indicate that the device exhibits both photodiode and photocapacitor behavior. We called this device as FYTRONIX device. The photoresponse behavior of the FYTRONIX device is controlled simultaneously by frequency and electric field. The FYRONIX device can be used as a photoresponse sensor in optoelectronic applications. [ABSTRACT FROM AUTHOR]

A novel AIE active Schiff base compound (receptor 1) has been designed, synthesized and characterized spectroscopically. Receptor 1 show weak emission in solution state but emit strongly in solid state. The investigation on the AIE behavior of receptor 1 using solvent-non-solvent (THF-Water) interaction reveals a maximum PL intensity on reaching the water fraction 90% ( f w = 90) due to nanoaggregation. Furthermore, demonstration of metal ion sensing application of receptor 1 unravel that it could act as selective and sensitive sensor for Cu 2 + ions in aqueous solution via fluorescence “turn-off” manner. The quenching behavior of receptor 1 in presence of Cu 2 + ions were evaluated using Stern-Volmer plot. [ABSTRACT FROM AUTHOR]

In this paper, we present design and simulation of the compact planar dipole antenna on fully flexible nitrile butadiene rubber polymer composite for body area network applications. A three-layer human tissue model is used to numerically analyse the performance of the antenna, including the human body effect. The proposed antenna achieves stable on-body performance: |S11| varies from -19.45 dB (in free space) at 2.46 GHz resonant frequency to -20.62 dB (on the skin) at 2.44 GHz resonant frequency. Additionally, the specific absorption rate (SAR) of the proposed antenna is evaluated. It was found that the maximum 1 g average SAR value is only 0.20 W/kg for an input power of 100 mW at a distance 2 mm away from tissue model. Simulated and measured results are presented to demonstrate the validity of the proposed antenna. Furthermore, the proposed antenna offer advantages of being compact, of low profile, cheap and easy to fabricate. [ABSTRACT FROM AUTHOR]

We propose ANN-based models to analyze and extract the internal parameters of a Schottky photodiode (SPD) without presenting them with any knowledge of the highly nonlinear thermionic emission (TE) expression of the device current. We train, evaluate and demonstrate the ML models on thirty-six private datasets from three previously published devices, which denote current responses under illumination and ambient temperature of graphene oxide (GO) doped p-Si Schottky barrier diodes (SBDs). The GO doping levels are 0%, 1%, 3%, 5%, and 10%. The illumination ranged from dark (0 mW/cm2) to 30 mW/cm2. The predictions are then made completely at the intensity of 60 mW/cm2. For each diode, some values of the barrier height (ϕ ), ideality factor (n), and series resistance ( R s ) independently calculated using the Cheung–Cheung method were included in the training dataset. The predictions are done at unspecified intensities on the model development data at 80 and 100 mW/cm2, and on external data at 5% and 20% GO doping which were not part of the development dataset. The ANN achieved a mean square error and mean absolute error score below 0.003 across all datasets. This demonstrates the effective learning capabilities of the ANN models in accurately capturing the photo responses of the photodiodes and accurately predicting the internal parameters of the Schottky Barrier Diodes (SBDs), all without relying on an inherent understanding of the thermionic emission (TE) equation for SBDs. The ANN models achieved high accuracy in this process. The proposed ML models can significantly reduce analysis time in device development cycles and can be applied to other datasets in various fields. [ABSTRACT FROM AUTHOR]

CuFe 1 − x Sn x O 2 composite thin film/ p -type silicon diodes were prepared on substrate by sol-gel method ( x = 0.00, 0.01, 0.03, 0.05, 0.07). The structure of CuFe 1 − x Sn x O 2 composite thin films was studied using XRD analysis and films exhibited amorphous behavior. The elemental compositions and surface morphology of the films were characterized using SEM and EDX. EDX results confirmed the presence of the compositional elements. The optical band gap of CuFe 1 − x Sn x O 2 composite thin films was determined using the optic spectra. The optical band gaps of the CuFe 1 − x Sn x O 2 composite thin films were calculated using optical data and were found to be 3.75, 3.78, 3.80, 3.85 and 3.83 eV for x = 0.00, 0.01, 0.03, 0.05 and 0.07, respectively. The photoresponse and electrical properties of the Al/CuFe 1 − x Sn x O 2 / p -Si/Al diode were studied. The barrier height and ideality factor were determined to be averagely 0.67 eV and 2.6, respectively. The electrical and photoresponse characteristics of the diodes have been investigated under dark and solar light illuminations, respectively. The interface states were used to explain the results obtained in present study. CuFe 1 − x Sn x O 2 photodiodes exhibited a high photoresponsivity to be used in optoelectronic applications. [ABSTRACT FROM AUTHOR]

In present investigation, we limelight the key electro-optical properties including electronic structure, optical, charge transport and nonlinear optical properties of two novel chalcone derivatives (( E )-1-(2,5-Dimethyl-3-Thienyl)-3-(2-hydroxyphenyl)prop-2-en-1-one ( chalc1 ) and (2 E )-3-[4-(Dimethylamino)phenyl]-1-(2,5-dimethyl-3-Thienyl)prop-2-en-1-one ( chalc2 ). The ground (S 0 ) and excited state (S 1 ) geometries are optimized using B3LYP/6-31G** and TD-B3LYP/6-31G** levels of theory, respectively, which show reasonably good agreement to the available experimental data of respective crystal structures. A comprehensive electronic structure-property relationship is elucidated through the prism of frontier molecular orbitals (FMOs), orbital energy gap (E g ) analysis, density of states (DOS), as well as molecular electrostatic potential (MEP) plots. The effect of electron donating groups (-OH and −N(CH 3 ) 2 ) is investigated on the absorption and emission wavelengths, ionization potentials (IP), electron affinities (EA), reorganization energies. Finally, the n -channel charge transport nature of these compounds is considered on the bases of our calculated transfer integrals and intrinsic mobilities. [ABSTRACT FROM AUTHOR]

Coumarin doped with poly(3-hexylthiophene)/p-Si photodiodes were prepared by the drop-casting technique. The current–voltage characteristics of the prepared diodes with the structure of Al/P3HT:Coumarin/p-Si/Al diodes were investigated under dark and various illumination intensities using both I–V and C–V methods. Using both illuminated DC and transient I–V and C–V measurements, the photocurrents are shown to depend on light intensity with the P3HT:Coumarin ratio influencing photoresponsivity. The photocurrents increase with increasing illumination intensity. C–V measurements show that the capacitance of the diode depends on voltage, frequency and illumination, indicating the existence of a continuous distribution of interface states that can be described in terms of organic-organic polymer blend domains in additional to the well studied metal-semiconductor interface states. The best responses were found to be for the diode having 10% Coumarin weight. These results suggest that the Al-p-Si/P3HT:Coumarin/Al diode can be used as a photosensor. [ABSTRACT FROM AUTHOR]

The low activation barrier to the Cope rearrangement of semibullvalenes has been attributed to the inherent ring-strain of this nucleus. Appropriate, Dewar-Hoffmann, substitution of semibullvalene results in the stabilization of the transition state and a further lowering of the Cope barrier. An alternative proposal for lowering/eliminating this barrier is the use of strain to destabilize the localized semibullvalene. Using density functional and Hartree-Fock calculations, we predict that additionally straining the semibullvalene nucleus, by small ring annelations, will lead to a lowering of the Cope barrier and ultimately to ground state neutral homoaromatics. [ABSTRACT FROM AUTHOR]

Using first-principle methods, several key electronic, optical and nonlinear optical properties are calculated for two recently synthesized chalcone derivatives i.e. (2E)-3-(4-methylphenyl)-1-(3-nitrophenyl)prop-2-en-1-one (comp. 1 ) and (2E)-3-[4-(dimethylamino)phenyl]-1-(3-nitrophenyl)prop-2-en-1-one (comp. 2 ). The calculation of dipole moment, polarizability <α>, anisotropy of polarizability as well as second hyperpolarizability (usually considered as a signature for two photon absorption phenomenon) are performed using density functional theory methods at PBE0/6-311G** level of theory. The linear average polarizability <α> for comp. 1 and comp. 2 are found to be 32.15 × 10 −24 and 38.76 × 10 −24 esu, respectively. Similarly, the second hyperpolarizability <γ> amplitudes of comp. 1 and comp. 2 are found to be reasonably larger mounting to 79.31 × 10 −36 and 181.36 × 10 −36 esu, respectively. The importance of donor end is determined by comparing p -methylphenyl group of comp. 1 with that of N , N -dimethylaniline group of comp. 2 that results a remarkable increase in its <γ> amplitude, which is ∼2 times larger as compared with that of comp. 1 owing to the stronger donor-acceptor configuration of comp. 2 . Interestingly, a comparison of average static third-order nonlinear polarizabilities <γ> shows that <γ> amplitudes of comp. 1 and comp. 2 are ∼13 times and ∼29 times larger than that of para -nitroaniline (a typical standard push-pull NLO-phore) at the same PBE0/6-311G** level of theory, which indicates a real time NLO application of our titled compounds. Time dependent density functional theory (TD-DFT) calculations along with frontier molecular orbitals, density of states (DOS), second hyperpolarizability density analysis and molecular electrostatic potential (MEP) diagrams are used to trace the origin of electro-optical as well as structure property relationships. [ABSTRACT FROM AUTHOR]

A dihydroquinazolinone derivative 2-(2,4-Dimethoxy-phenyl)-2,3-dihydro-1H-quinazolin-4-one ( 1 ) was synthesized and characterized by 1 H NMR, 13 C NMR and FT-IR and its spectral, photophysical, intramolecular charge transfer characteristics were studied by absorption and emission spectroscopy. The compound exhibits significant changes in their photophysical properties depending on the solvent polarity. The observed bathochromic emission band and difference in Stokes shift on changing the polarity of the solvents clearly demonstrate the highly polar character of the excited state, which is also supported by the enhancement of dipole moment of the molecule upon photoexcitation. Solvatochromic shift methods based on Lippert–Mataga, Bakhshiev-Kawski and Reichardt's correlations were applied to calculate the ground, excited and change in dipole moments. The effect of solute–solvent interactions on compound 1 was studied using multi-parameter solvent polarity scales proposed by Kamlet–Taft and Catalan. The interactions of various metal ions on compound 1 were also studied using steady state fluorescence measurements. The emission profile reveals that it acts as on-off type fluorescent chemosensor for selective and sensitive detection of Hg 2 + ions. Complexation stoichiometry and mechanism of quenching were determined from Benesi–Hildebrand and Stern-Volmer plot. [ABSTRACT FROM AUTHOR]

The ground state neutral geometries of some natural tropolones, i.e. stipitatonic acid (AF1), stipitalide (AF2), stipitaldehydic acid (AF3) and methyl stipitate (AF4) have been optimized by using Density Functional Theory (DFT) at B3LYP/6-31G*, B3LYP/6-31G**, B3LYP/6-31+G* and B3LYP/6-31+G** levels of theory. The excited state geometries of AF1-AF4 were optimized by adopting the Time Dependent Density Functional Theory (TDDFT) at the same levels of theory. The frequencies and cation species of AF1-AF4 were also computed at all the above mentioned levels of theory. We shed light on the electro-optical and molecular properties, e.g. energy gaps, highest occupied molecular orbitals, lowest unoccupied molecular orbitals, absorption wavelengths, electronegativity (χ), hardness (η), electrophilicity (ω), softness (S), electrophilicity index (ωi) and the radical scavenging activity (RSA). Hydrogen atom transfer (HAT) and one-electron transfer mechanisms have been discussed to shed light on the RSA. The smallest ionization potential and bond dissociation energy of AF4 are revealing that this compound would have more RSA than those of other counterparts. [ABSTRACT FROM AUTHOR]

Pyrazole compounds are gaining noteworthy attention in our daily life from better biological active to the semiconducting materials. Present work deals in depth study of indigenously synthesized pyrazole compound, i.e., 2-[(3,5-dimethyl-1-phenyl-1H-pyrazol-4-yl)methylidene]indan-1,3-dione ( DMPI ) with respect to the structural, electronic, optical and charge transport properties. The ground and excited state geometries were optimized by applying density functional theory (DFT) and time dependent DFT, respectively. The frontier molecular orbitals (FMOs) have been spotlighted. The comprehensible intra-molecular charge transfer (ICT) from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) was observed. The absorption and emission wavelengths were studied at the TD-B3LYP/6-31G** level of theory. The total and partial density of states (T/PDOS) has been studied to understanding the contribution of different states in the electronic properties. The ionization potentials (IP), electron affinities (EA), reorganization energies, transfer integrals, intrinsic mobility and structure-property relationship have been discussed intensively. The smaller hole reorganization energy and superior transfer integral values resulting improved hole intrinsic mobility than the electron ones is revealing that DMPI would be better hole transport material. [ABSTRACT FROM AUTHOR]

The isoxazole derivatives gained significant attention in our daily life from better biological activity to the semiconducting materials. This study deals in depth investigation of two isoxazole derivatives, i.e. 2-[(E)-(3,4-Dimethylisoxazol-5-yl)iminomethyl]phenol ( 1) and 1-[(E)-(3,4-Dimethylisoxazol-5-yl)iminomethyl]-2-naphthol ( 2) with respect to the geometric, charge transport, optoelectronic and nonlinear optical properties by density functional theory (DFT) and time-dependent DFT. The comprehensible intra-molecular charge transfer (ICT) was conceived from HOMOs to LUMOs. Strength of the electron donor groups was investigated on the absorption wavelengths, emission wavelengths, ionization potentials (IPs), electron affinities (EAs), total/partial densities of states and structure-property relationship. The smaller hole reorganization energies and superior transfer integrals of isoxazole derivatives ( 1 and 2) than the electron ones are leading to higher hole intrinsic mobility values as compared to the electron mobility exhibit that these systems would be good hole transport contenders. The first hyperpolarizability values are about 19 and 21 times larger than that of urea suggesting that 1 and 2 can also be considered as potential contestants for NLO applications as well. The FMO, MEP, IP, EA, NLO and SAR of isoxazole derivatives were studied by DFT and TDDFT. The effect of donor strength was discussed on optoelectronic and charge transport properties. The smaller hole reorganization energies and superior transfer integrals of both the derivatives is leading to higher hole intrinsic mobility values as compared to the electron mobility exhibit that these systems would be good hole transport contenders. [ABSTRACT FROM AUTHOR]

We present herein the effect of varied humidity levels on the electrical parameters of the (E)-2-{4-[2-(3,4,5-trimethoxybenzylidene) hydrazinyl]phenyl}ethylene-1,1,2-tricarbonitrile (TMBHPET) organic dye based humidity sensor. TMBHPET dye has been synthesized bearing an additional methoxy group substituent at the terminal benzene ring of previously reported (E)-2-(4-(2-(3,4-dimethoxybenzeylidene)hydrazinyl)phenyl)ethane-1,1,2-tricarbonitrile (DMBHPET) dye. The strategic dye design is believed to increase the π-electron polarizability in the dye structure. Capacitive type humidity sensor has been fabricated in planar geometry of Al/TMBHPET/Al and its capacitance has been monitored as a function of relative humidity (RH) level at varied frequencies of ∼1 v AC input bias. A maximum sensitivity ∼46 fF/%RH at 1 kHz has been observed which is almost seven times higher as that of DMBHPET based humidity sensor which may be attributed to the porous surface morphology of TMBHPET sensing film. The sensor has also shown reversible changes in its capacitance with variation in humidity level and hysteresis value has been observed to be 2.4%. The motive of the present study was to increase the sensing parameters of the previously reported humidity sensor utilizing DMBHPET dye, which has been successfully achieved. [ABSTRACT FROM AUTHOR]

Using the density functional theory methods, we effectively tune the second-order nonlinear optical (NLO) properties in some chalcone derivatives. Various unique push–pull configurations are used to efficiently enhance the intramolecular charge transfer process over the designed derivatives, which result in significantly larger amplitudes of the first hyperpolarizability as compared to their parent molecule. The ground state molecular geometries have been optimized using B3LYP/6-311G** level of theory. A variety of methods including B3LYP, CAM-B3LYP, PBE0, M06, BHandHLYP and MP2 are tested with 6-311G** basis set to calculate the first hyperpolarizability of parent system 1 . The results of M06 are found closer to highly correlated MP2 method, which has been selected to calculate static and frequency dependent first hyperpolarizability amplitudes of all selected systems. At M06/6-311G** level of theory, the permanent electronic dipole moment (μ tot ), polarizability (α 0 ) and static first hyperpolarizability (β tot ) amplitudes for parent system 1 are found to be 5.139 Debye, 274 a. u. and 24.22 × 10 −30 esu, respectively. These amplitudes have been significantly enhanced in designed derivatives 2 and 3 . More importantly, the (β tot ) amplitudes of systems 2 and 3 mount to 75.78 × 10 −30 and 128.51 × 10 −30 esu, respectively, which are about 3 times and 5 times larger than that of their parent system 1 . Additionally, we have extended the structure-NLO property relationship to several newly synthesized chalcone derivatives. Interestingly, the amplitudes of dynamic frequency dependent hyperpolarizability μβ ω (SHG) are also significantly larger having values of 366.72 × 10 −48 , 856.32 × 10 −48 and 1913.46 × 10 −48 esu for systems 1 – 3 , respectively, at 1400 nm of incident laser wavelength. The dispersion behavior over a wide range of change in wavelength has also been studied adopting a range of wavelength from 1907 to 544 nm. Thus, the present work realizes the potential of designed derivatives as efficient NLO-phores for modern NLO applications. [ABSTRACT FROM AUTHOR]

A metal-insulator-semiconductor (MIS) diode based on the Bi 2 Se 3 3D topological insulator on p-Si substrate was fabricated for use as a photodiode with the Al/p-Si/Bi 2 Se 3 /Al structure. The current-voltage, series resistance, and impedance characteristics were investigated using standard techniques and a new series resistance compensated method. The application of the method is described in a brief algorithm. The diode exhibits an apparent rectification ratio of 3700 and the R s compensated rectification ratio that is almost 1.5 times higher, thus suggesting a new method to determine the true rectification ratio of a diode. The diodes have an ideality factor greater than unity, a barrier height of 0.647 eV, and a built-in potential of 0.476 V. The maximum density of the interface state of the diode is 5.1 × 1012 eV−1cm−2 over the reverse bias range of − 3–0 V. This is comparable to those of oxide-based diodes, but unexpected since oxygen-induced defect states were thought unlikely. When compensating for the effects of series resistance, the dark current of the diode is found to be 2.5 nA. The open-circuit voltage of the diode was estimated at around 0.244 V at 100 mW/cm2 solar light illumination, with an estimated efficiency of at most 2.9%. These values are typically reported bismuth-based topological insulator/Si diodes. This shows that the diode can be used as a low-power solar cell. The photoresponses of the device show that it is suitable as a fast MIS photodiode over a wide range of incident intensity. [Display omitted] • Bi2Se3 3D-topological insulator based diode for photoconductive sensing. • High open-circuit voltage of 0.244 V and short-circuit current up to 57.8 uA for photovoltaics. • Application of powerful new series resistance compensation technique for analysis. • New method suggested for true rectification ratio of diodes with series resistance. • Devices demonstrate efficiencies of up to 2.9. [ABSTRACT FROM AUTHOR]

The quinazolinone compounds (1 and 2) in this work were examined for their in vitro antibacterial activities against gram-positive (Staphylococcus aureus) and gram-negative bacteria (Klebsiella pneumonia, Proteus bacilli and Shigella flexneri). Compared to the reference antibiotic chloramphenicol, these compounds showed high antibacterial activities against studied strains with inhibition zones observation. The ground state geometries have been optimized by using density functional theory (DFT) at B3LYP/6-31G* level of theory. The absorption spectra have been calculated by using time dependent density functional theory (TDDFT) with and without solvent. The effect of different functionals (B3LYP, MPW1PW91, and PBE1PBE) on the absorption wavelengths has been studied. The ionization potential (IP), electron affinity (EA), energy gap (Egap), electronegativity (χ), hardness (η), electrophilicity (ε), softness (S) and electrophilicity index (εi) were computed and discussed. The nonlinear optical (NLO) properties vary by changing the theory (DFT to HF) or functional (B3LYP to CAM-B3LYP). The physicochemical parameters have been studied by quantitative structure-activity relationship (QSAR). The computed properties of investigated compounds have been compared with the Chloramphenicol as well as available experimental data. [ABSTRACT FROM AUTHOR]

The structural, electro-optical and charge-transport properties of compound trans -3-(3,4-dimethoxyphenyl)-2-(4-nitrophenyl)prop-2-enenitrile (DMNPN) were studied using quantum chemical methods. The neutral, cation and anion molecular geometries were optimized in the ground state using density functional theory (DFT) at the restricted and unrestricted B3LYP/6-31G** level of theory. The excited state geometries were optimized by applying time-dependent DFT at the TD-B3LYP/6-31G** level of theory. The absorption and fluorescence wavelengths were calculated at the TD-CAM-B3LYP/6-31G** and TD-LC-BLYP/6-31G** levels of theory. The distribution pattern of the charge densities on the highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) are discussed. Intramolecular charge transfer was observed from the dimethoxyphenyl to (nitrophenyl)prop-2-enenitrile moieties. The detailed charge-transport behavior of the DMNPN molecule is investigated based on its ionization potential, electron affinity, hole and electron reorganization energies, hole and electron-transfer integrals, and hole and electron intrinsic mobilities. The total/partial densities of states and structure–property relationship are discussed in detail. The higher computed hole intrinsic mobility than electron intrinsic mobility reveals that DMNPN is an efficient hole-transport material. [ABSTRACT FROM AUTHOR]

We have synthesized the two donor-bridge-acceptor organic dyes (hydrazone dye 1 (HD1) and hydrazone dye 2 (HD2)) with the aim to enhance intra-molecular charge transfer then characterized by FTIR and NMR. The ground state geometries have been optimized at three different levels of theories, i.e., B3LYP/6-31G ∗ , B3LYP/6-31G ∗∗ and Hartee–Fock HF/6-31G ∗∗ . The absorption spectra and oscillator strengths in different solvents have been computed and compared with the experimental data. The vibrational spectral assignments have been performed on the recorded FTIR spectra based on the theoretical predicted wavenumbers at three different levels of theories. The effect of different solvents (CHCl 3 , CH 3 CN and C 2 H 5 OH) has been studied on the absorption wavelengths. Furthermore, we have computed the ionization potentials, electron affinities and reorganization energies of studied compounds and shed light on the charge transport properties. The hetero-junction solar cell devices were fabricated by organic–inorganic hetero-junction (Si/TiO 2 /dye) then the efficiency has been measured by applying the incident power 30, 50 and 70 mW/cm 2 . The maximum efficiency 3.12% has been observed for HD1. [ABSTRACT FROM AUTHOR]

The 2-{4-[2-benzylidenehydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 1), 2-{4-[2-(1- naphthylmethylene)hydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 2) and 2-{4-[2-(9-anthrylmethylene)- hydrazino]phenyl}ethylene-1,1,2-tricarbonitrile (System 3) were synthesized by direct tricyanovinylation of hydrazones. The bathochromic shift in absorption spectra has been observed by increasing the solvent polarity. The FTIR spectra of these new dyes exhibited three important absorption bands. The first band centered near 3260 cm-1 in System 1 while 3208 cm-1 and 3211 cm-1 in System 2 and System 3 for the • NH absorption, respectively. The second band is a sharp absorption band in the region of 2212-2209 cm-1, which was attributed to the cyano group absorption. The third is an absorption band in the region of 1611-1603 cm-1 ascribed for the C=N. Density functional theory (DFT) calculation of relative energies, relative enthalpies and free energies shows that E isomers are the most stable except System 3 in which the most stable is Z isomers. The conformational energy profile shows two maxima near (-90 and 90°) while three local minima observed at (-180, 0 and 180) for N1-N2-C1-C2 torsional angle. The highest occupied molecular orbitals (HOMOs) are localized on the whole molecules while lowest unoccupied molecular orbitals (LUMOs) are distributed on the tricarbonitrile. [ABSTRACT FROM AUTHOR]