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Nonlinear and linear optical traits of vanadio–tellurite glasses in the form 50TeO 2 -(50-x)V 2 O 5 -xK 2 O (where x = 0–20 mol% (abbreviated as TVK glasses) were investigated. Besides, gamma ray shielding parameters were assessed utilizing the FLUKA simulation code. Results revealed that the molar refraction (Rmolar) varied from 31.122 to 26.400 (cm3/mol), while molar polarizability (αmolar) varied from 12.350 × 10−24 to 10.476 × 10−24 cm3. The static dielectric constant (εstatic) was within 10.298–6.789. The optical electronegativity (χ*) varied from 0.319 to 0.626 for TVK glasses. The nonlinear refractive index (nOptical) diminished from 5.996 × 10−10 to 1.109 × 10−10 (esu), while the nonlinear optical susceptibility (χ3) diminished from 5.107 × 10−11 to 0.767 × 10−11 (esu) with the V 2 O 5 /K 2 O substitution in the glasses. Gamma ray attenuation coefficients such as μ and μ/ρ were calculated for six different photon energies in the range of 0.284–1.275 MeV. Both μ and μ/ρ were used to evaluate the transmission factors (HVL and MFP) and the effective atomic number (Z eff). The Z eff parameter was useful to give a full understanding of the gamma ray shielding performance of the TVK glasses under V 2 O 5 /K 2 O substitution. Finally, the parameters of gamma ray shielding were compared with ordinary and commercial shielding materials. [ABSTRACT FROM AUTHOR]

The mechanical features, linear and non-linear optical properties and the radiation (beta/gamma) shielding competences of (90-x)TeO 2 –5CaO–5Na 2 O-xZnO: x = 5–20 mol% glasses were studied. Results revealed that the molar polarizability (αMol.) decreased from 6.215 × 10−24 to 6.009 × 10−24 cm3 and the molar refraction (RMol.) changed from 15.664 to 15.143 (cm3 mol−1) as the ZnO content increased from 5 to 20 mol%. The criterion of metallization (MCri.) was observed in the range of 0.419 to 0.384. The factor of optical transmission (TOpt.) decreased from 0.814 to 0.788. The dielectric constant (εSta.) varied from 3.763 to 4.202. The electro-negativity (χ*) decreased from 0.943 to 0.792. The non-linear optical susceptibility (χ3) changed from 3.984 × 10−13 to 7.185 × 10−13 esu. The non-linear refractive index varied from 0.739 × 10−11 to 1.320 × 10−11 esu. The radiation shielding properties of the chosen glasses (TCN-Z05, TCN-Z10, TCN-Z15, and TCN-Z20) were tested in terms of gamma radiation (photons up to 1.275 MeV) and beta radiation (electrons up to 0.723 MeV). The gamma shielding investigations were performed by using FLUKA and XCOM platforms. The beta shielding study was carried out via ESTAR program by estimating TSP for all the chosen glasses. From the view of practical application, it is found that the HVL and MFP values of the chosen glasses are evidently lower than those of ordinary concrete and RS-253-G18 commercial glass, while they are higher than those of RS-360 glass at low energies. [ABSTRACT FROM AUTHOR]

We report on ab-initio all electrons spin-polarised density-functional calculations for the band structure, optical spectra and magnetisation of bulk MnAs with NiAs-type lattice structure with emphasis on their dependence on pressure. The aim of this contribution is to show how the investigated properties behave upon compression. Our findings are compared when possible with those reported in the literature showing generally reasonable accordance. Our results indicate that the material under load exhibits a metallic character. The studied optical spectra show an anisotropic character between the x and z directions and are shifted downwards with raising pressure. The predicted static refractive index values depend on the direction, spin channel and pressure. The effect of the spin channel on the electronic and optical properties is found to be important. At zero pressure, MnAs reaches a total magnetic moment of the order of 5.69 μB per cell which decreases with raising pressure. The material of interest can be regarded as a good candidate for use in fabricating novel functional materials due to the spin degree of freedom. [ABSTRACT FROM AUTHOR]

We present a theoretical study on electronic structure and chemical trends of zinc-blende GaP under compression up to 100 kbar obtained from a pseudopotential approach calculations. The influence of high pressure on the features of interest has been examined and reported. The dynamics of chemical bonds in the compound in question is investigated by analyzing the profiles of the electron charge densities. Our findings show generally a good accord with experiment. The present study can contribute in the understanding of the pressure effects on the electronic properties and chemical bonding of GaP material. [ABSTRACT FROM AUTHOR]

A pseudopotential approach is used to study the lattice and elastic properties of the wide band-gap GaN at zero and high pressures up to 120 kbar. When the pressure is 0 kbar, our findings are generally in agreement with the data reported in the literature. The pressure dependence of lattice constant, polarity, transverse effective charge, elastic constants and their related mechanical parameters, and microhardness has been examined and discussed. Our results show that all these features exhibit a monotonic behaviour against pressure. Upon compression up to 120 kbar, our results suggest that the material in question remains mechanically stable with higher stiffness, becomes more resistant to the deformations or deflections and its chemical bond and rigidity become stronger. [ABSTRACT FROM AUTHOR]

Abstract Incorporated titanium oxide to bioglasses with novel composition as: 40P2O5- 20Na2O- 10Ca(OH)2- 20CaCl2–8.0ZnO- 1.0TiO2 (labeled BGTi) was tested for its antimicrobial activity, anti-proliferative/cytotoxicity against normal and activated splenic cells in vitro , anticancer activity, in vivo immunologic and hypersensitivity responses, in vivo and in vitro cytotoxicity effects and in vitro effects of activated splenic cells on BGTi. These results showed that BGTi had antimicrobial activities against Gram negative and positive bacteria as well as fungi. The prepared bioglasses BGTi had no cytotoxic or proliferative effects on activated splenic cells while showed anti-proliferative/cytotoxicity against normal splenic cells. It was cytotoxic to HepG2 cells. In vivo test demonstrated that BGTi is an inert material which did not stimulate the immune system or caused local reactions. The products of activated splenic cells did not cause any changes in the structure of BGTi also it did not cause any acute cytotoxicity or lysis to RBCs. TiO2 is an inert material which did not cause immune stimulation or hepatic cytotoxicity. BGTi did not affect by lytic products of immune cells hence, it can be considered as a safe and ideal material for implantation inside the body of living organisms. Finally we investigated the structure of the bioglasses BGTi by using Raman spectra. Highlights • Incorporated titanium oxide to bioglasses with novel composition was tested for its antimicrobial activity, anti-proliferative/cytotoxicity. • BGTi had antimicrobial activities against Gram negative and positive bacteria as well as fungi. • BGTi did not cause any acute cytotoxicity or lysis to RBCs. • It can be considered as a safe and ideal material for implantation inside the body of living organisms. [ABSTRACT FROM AUTHOR]

Abstract In current work, thin films of CdS with alike thickness were fabricated by chemical bath deposition by varying the deposition time. Thickness of films was measured to be ∼200, 250 and 300 nm using Alfa step stylus profilometer. As thickness play significant role hence thickness dependent structural, vibrational, morphological, optical and third order nonlinear optical (TONLO) studies are exclusively explored. The XRD and FT-Raman studies revealed an enhancement in crystallinity with increasing thickness of films and also confirmed non existence of any impurity peak. Crystallite size evaluated from Scherrer's rule is found to be increased from 21 to 30 nm with increasing the thickness of films. Scanning electron microscopy images demonstrates the modification of spherical nanoparticles to nano needles with increase of thickness of films. Average size of grains are intuited to be in 30–65 nm range. Transmission spectra showed high transparency for films of 200 nm thickness and later reduced with increase of thickness. Direct energy gap was attained in range of 2.2–2.3 eV. Stable values of k and n indicates defect free films. The n 2 and χ3 values are found to very high which are in range of 3.15–8.67 (×10−6) and 1.11 to 1.47 (×10−1), respectively. Such transparent films with higher TONLO susceptibility values are potential candidates for optoelectronic device applications. [ABSTRACT FROM AUTHOR]

Abstract Growth of pure and oxalic acid (OA) added zinc thiourea chloride (ZTC) crystals was achieved by slow evaporation method. The structural parameters of these have been confirmed by single crystal XRD. Incorporation/presence of OA in ZTC crystal was established by EDS. Optical transparency of grown crystals has been evaluated in 200–900 nm region and linear optical constants are examined in visible region using the UV–visible transmittance data. SHG efficiency of OA:ZTC crystal is observed to be 4.51 times that of ZTC crystal tested by Kurtz-Perry method. Z-scan measurement was done at 632.8 nm to confirm the nature of third order nonlinearity of OA:ZTC crystal and third order nonlinear susceptibility (χ(3)), refraction (n 2) and absorption coefficient (β) were evaluated. Mechanical behavior of OA:ZTC crystal is investigated using Vicker's microhardness studies. Dielectric properties of crystals were comparatively investigated at different temperature. The thermal stability and melting point of OA doped ZTC crystal material has been determined employing thermogravimetric and differential scanning calorimetric analysis. Graphical abstract Image 1 Highlights • OA increased the optical transparency by 22% and band gap of ZTC crystal. • SHG efficiency of OA-ZTC crystal is 4.51 times that of ZTC crystal. • OA altered the refraction nonlinearity of ZTC and triggered the strong kerr effect. • The n 2 and χ3 of OA-ZTC crystal is 1.72 × 10−9 cm2/W and 1.31 × 10−4 esu, respectively. • OA improved the dielectrics of ZTC crystal, crucial for electro-optic devices. [ABSTRACT FROM AUTHOR]

Abstract In this paper an attempt was made to investigate the compositional, microstructural, thermal and optical properties of 40P 2 O 5 - 30ZnO- 20BaF 2 - 3.8K 2 TeO 3 - 1.2Al 2 O 3 - 5Nb 2 O 5 - 30,000 ppm Er 2 O 3 (PZBKTANEr) novel glasses fabricated by the melt quench technique. The amorphous nature of the glasses was confirmed by X-ray diffraction studies. We estimated the glass transition temperature and thermal stability against the crystallization of present glasses by using differential thermal analysis (DTA). The results of the differential thermal analysis (DTA) indicate that (PZBKTANEr) glasses have a high thermal stability and low tendency to crystallization.The optical absorption edge has been evaluated within the Urbach approach by using UV–vis-NIR spectroscopy. Moreover, the Judd– Ofelt parameters Ω 2 , Ω 4 and Ω 6 the oscillator strength type transition probabilities, spectroscopic quality factors, branching ratios and radiative lifetimes of several excited states of Er3+ have been evaluated. The classical Mc Cumber theory was used to evaluate the emission cross-sections for the 4I 15/2 → 4I 13/2 transition at a wavelength of around 1.54 μm. Gain cross-section for the Er3+ laser transition 4I 15/2 → 4I 13/2 was obtained. The effective emission cross section bandwidth FWHM (75.924 nm) and height stimulated emission cross-section (5.5 × 10−21 cm−2) of present glasses were reported. Hence the thermal and spectroscopic properties indicate that this glass doped with Er3+ can be used for application of the optical device. Furthermore the structure of this glass was analyzed by Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract The temperature dependence of the band gaps, refractive index, high-frequency and static dielectric constants and optical phonon frequencies in GaAs has been computed by using a pseudopotential approach. Our findings for all features of interest at given temperatures yielded values that agree with those previously reported. The variation of the features being studied here versus temperature showed a monotonic behavior. The transverse optical (TO) and longitudinal optical (LO) phonon frequencies are shifted towards low frequencies when the temperature is raised from 0 to 600 K. The change in the LO-TO splittings by raising temperature reflects the change in the ionicity character of the material under investigation. [ABSTRACT FROM AUTHOR]

Highlights • Electron scattering in Si x Ge 1 − x and GaAs x N 1 − x targets. • Modeling of penetration range of electrons impinging on Si x Ge 1 − x and GaAs x N 1 − x targets. • Modeling of transport cross-sections of electrons in Si x Ge 1 − x and GaAs x N 1 − x targets. • Backscattering coefficient of electrons penetration in Si x Ge 1 − x and GaAs x N 1 − x targets. • Composition dependence of electron range and backscattering coefficient in Si x Ge 1 − x and GaAs x N 1 − x targets. Abstract The alloy composition dependence of penetration range and backscattering coefficient of electrons normally impinging on Si x Ge 1 − x and GaAs x N 1 − x semiconductor alloys targets for beam energies in the range 0.5–3.5 keV has been investigated. The electron penetration range is calculated using the Ashley's model. The electron backscattering coefficient is determined using both the Vicanek and Urbassek theory where the transport cross-sections are obtained more accurately via an improved approximation and Monte Carlo method in which the inelastic scattering processes are treated via Ashley's optical model. Our results regarding the electron backscattering coefficient for Si and Ge targets are found to be much higher than those of experiment when using the Vicanek and Urbassek theory. However, the use of Ashley's model via Monte Carlo method gives results that are in reasonably good accord with the experimental data reported in the literature in the low energy regime being considered here. [ABSTRACT FROM AUTHOR]

Based on a pseudopotential approach under the virtual crystal approximation, the elastic modulus of InxAl1 − xAsySb1 − y quaternaries lattice-matched to InP, GaSb and InAs substrates has been investigated. Our findings show a reasonably good accord with experiment. The dependence of the elastic features of interest on the indium concentration x shows a monotonic behaviour when InxAl1 − xAsySb1 − y is lattice-matched to InP substrate. In that case, the elastic constants have larger values and the material system of interest becomes less harder and its rigidity becomes weaker. The mechanical stability criteria is verified in terms of elastic constants and shows that InxAl1 − xAsySb1 − y is mechanically stable for each x and substrate being considered here. The change in indium content x and the substrate is found to have no much effect on both the Poisson ratio and machinability. The present study showed that a proper choice of the indium composition x and substrate may provide more diverse opportunities as regards the elastic modulus of InxAl1 − xAsySb1 − y. [ABSTRACT FROM AUTHOR]

A novel Er 3+ -doped fluorotellurite titanate glasses with the basic molar composition 75TeO 2 - 5Nb 2 O 5 - 5Bi 2 O 3 - 5TiO 2 - 10PbF 2 , 75TeO 2 - 5Nb 2 O 5 - 5Bi 2 O 3 - 5TiO 2 - 10PbF 2 - 10000 ppm Er 2 O 3 and 75TeO 2 - 5Nb 2 O 5 - 5Bi 2 O 3 - 5TiO 2 - 10PbF 2 - 20000 ppm Er 2 O 3 are explored with respect to possible applications as optical amplifiers. Their thermal and optical features were determined using differential scanning calorimetric (DSC), and UV–Vis–NIR spectroscopy, respectively. The glasses transition temperature T g , factor against crystallization S, optical energy gap and quantum efficiency were determined. Judd-Oflet parameters Ω t (t = 2, 4, 6), branching ratio, β, fluorescence full width at half maximum (FWHM) of NIR emission, and life time τ, of I 13/2 level have been evaluated. The glasses were characterized by a higher values of FWHM of NIR emission at 1.53 μm under excitation by wavelength 980 nm with respect to other glasses system doped by single Er 3+ ions. In the future these glasses can be fabricated as broadband fiber amplifier for the optical communication devices. The glasses studied glasses exhibit green emission under excitation wavelength of 445 nm. [ABSTRACT FROM AUTHOR]

The band structure of Al x Ga 1 − x Sb semiconducting ternary alloys and their related properties such as elastic constants, microhardness, transition pressure to the first phase, acoustic wave velocities and melting temperature have been investigated. The calculations are performed using a pseudopotential approach within the virtual crystal approximation which includes the effect of compositional disorder as an effective potential. Generally, our results are found to be in good accord with the experimental results. The composition dependence of all features of interest showed a monotonic behavior and suggests that the stiffness, hardness and structural stability becomes better in Al x Ga 1 − x Sb for higher Al concentrations. The bulk sound speeds and melting temperature are found to become larger when increasing the Al content. [ABSTRACT FROM AUTHOR]

The electron and positron chemical potentials, positron affinity and bulk lifetime as well as the positronium work function in InP are investigated. The emphasis of this work is on the hydrostatic pressure effect on these features. The calculations are performed with a pseudopotential approach and the independent particle model. All parameters of interest are found to vary monotonically with pressure. Our findings showed that under compression the positron annihilates differently in InP semiconductor compound. At zero pressure, the positron bulk lifetime is calculated to be 243.47 ps. However, upon compression it decreases almost linearly suggesting the decrease of the crystal ionicity under applied pressure. The positronium work function is found to increase with raising pressure which indicates that under compression less positronium atoms will be formed in InP sample surface and ejected into the vacuum. The parameters investigated in the present work are important in slow-positron-beam experiments. [ABSTRACT FROM AUTHOR]

Tellurite glass with composition 90TeO 2 -10Nb 2 O 5 -10ZnO in mol% codoped with x(Tm 2 O 3 /Dy 2 O 3 ), where x = 10,000, 20,000 and 30,000 ppm were prepared by quenching melting technique. The optical density and photoluminescence properties of this glass were studied. Spectroscopic parameters such as the absorption cross section, σ ab (λ), emission cross section, σ em (λ), effective band width, (Δλ), internal gain coefficient, g R (λ), and the chromaticity coordinates CIE of the emitted light for this glass were computed. The, ( σ e m ) , (Δλ), and σ g (λ) parameters increase from 5.95 × 10 −21 to 8.86 × 10 −21  cm 2 , from 123 to 127 nm and from 4.2 to 6.3 dB/cm, respectively when increasing Tm 3+ /Dy 3+ ions from 10,000 to 30,000 ppm in the host glass matrix. Compared the luminescence intensity and spectroscopic parameters in these glasses are greatly enhanced. From CIE results indicate that the emission color varied from blue to white can be achieved by tuning Tm 3+ /Dy 3+ ratio under excitation at 466 nm. The present glasses are found to be a suitable candidate for solid state laser material. [ABSTRACT FROM AUTHOR]

The electronic band structure and optical properties of In x Al 1-x As y Sb 1-y quaternaries under conditions of lattice mismatching and lattice matching to InP substrate have been investigated using a pseudopotential approach under the virtual crystal approximation. The extent of the indirect (Г-X)-to-direct (Г-Г) band gap transition in In x Al 1-x As y Sb 1-y /InP is found to occur at x = 0.38 which agrees reasonably with the data reported in the literature. The lattice mismatch percentage in the range −5%–0% is found to have no effect on the nature of the fundamental band-gap in In 0.50 Al 0.50 As y Sb 1−y which remains a direct (Г-Г) band-gap semiconductor. Trends in bonding and ionicity are discussed in terms of the antisymmetric gap and valence band width. The dependence of the refractive index on both indium concentration x in In x Al 1−x As y Sb 1−y /InP and lattice mismatch percentage in In 0.50 Al 0.50 As y Sb 1-y has been examined. Our results showed that more opportunities can be provided for all features of interest by a proper choice of the concentrations x and y (0 ≤ x ≤ 0.52, 0.56 ≤ y ≤ 1) and/or the lattice mismatch percentage. [ABSTRACT FROM AUTHOR]

New families from fluorotellurite glasses with composition 7.53 TeO 2 -7.31 LiNbO 3 -4.16 Nb 2 O 5 -10 BaF 2 -1.0La 2 O 3 , 72.53 TeO 2 -7.31 LiNbO 3 -10 Nb 2 O 5 -10 BaF 2 -1.0La 2 O 3 and 77.53 TeO 2 -7.31 LiNbO 3 -5 TiO 2 -10 BaF 2 -1.0La 2 O 3 in mol% were prepared. The thermal characterization and optical properties of these glasses were estimated by using differential scanning calorimetric, DSC, and UV–vis-NIR spectroscopy respectively. The results of thermal analysis indicate that 77.53 TeO 2 -7.31 LiNbO 3 -5 TiO 2 -10 BaF 2 -1.0La 2 O 3 glasses has high thermal stability and high factor against crystallization. The density and linear refractive index, n, of present glasses were measured. Also, the physical parameters such as; oxygen packing density, molar volumes, oxygen molar volume, molar refraction, metallization criterion, molar polarizability, third-order non-linear susceptibility and two photon absorption coefficients were calculated. It was found that, the linear refractive index increases otherwise decrease in the optical energy gap with increase Nb 2 O 5 concentration. On the basis on thermal and optical results of these glasses it can be concluded that fluorotellurite glasses tested can be used in optical application. [ABSTRACT FROM AUTHOR]

Based on a pseudopotential approach under the virtual crystal approximation that includes the effect of compositional disorder, the optical lattice vibration frequencies and polaron related parameters in zinc-blende Ga x In 1−x P have been studied. Our findings showed generally reasonably good accord with data in the literature. Other case, our results are predictions. The composition dependence of longitudinal optical (LO) and transverse optical (TO) phonon modes, LO-TO splittings, Frӧhlich coupling parameter, Debye temperature of LO phonon frequency, and polaron effective mass has been analyzed and discussed. While a non-monotonic behavior has been noticed for the LO and TO phonon frequencies versus Ga concentration x, a monotonic behavior has been observed for the rest of the features of interest. The information derived from this investigation may be useful for optoelectronic technological applications. [ABSTRACT FROM AUTHOR]

The dependence of the refractive index upon temperature in ZnSe 1-x S x has been investigated using a pseudopotential approach. Our findings are in very good accord with the available experimental and previous theoretical data. The composition dependence of the refractive index is found to be non-monotonous exhibiting a non-zero refractive index bowing parameters. The refractive index is shown to vary continuously and monotonically with raising temperature for each composition x. The temperature linear coefficient values of the refractive index have been reported and their dependence on S content has been examined. Besides, the refractive index bowing parameter and its dependence on temperature are presented and discussed. [ABSTRACT FROM AUTHOR]

The dependence on hydrostatic pressure of the electronic and optical properties of zinc-blende AlSb semiconducting material in the pressure range of 0–20 kbar has been reported using a pseudopotential approach. At zero pressure, our findings showed that the electron and heavy hole effective masses are 0.11 and 0.38 m 0 , respectively. Moreover, our results yielded values of 3.3289 and 11.08 for refractive index and high frequency dielectric constant, respectively. These results are found to be in good accord with experiment. Upon compression, all physical parameters of interest showed a monotonic behavior. The pressure-induced energy shifts for the optical transition related to band-gaps indicated that AlSb remains an indirect (Г-X) band-gap semiconductor at pressures from 0 to 20 kbar. The trend in all features of interest versus pressure has been presented and discussed. It is found that the lattice parameter is reduced from 0.61355 to 0.60705 nm when pressure is raised from 0 to 20 kbar. The present investigation may be useful for mid-infrared lasers applications, detectors and communication devices. [ABSTRACT FROM AUTHOR]

The effect of hydrostatic compression on elastic constants and related properties in InSb have been investigated using a pseudopotential approach. At zero pressure, our results are found to compare reasonably well with experiment. A monotonous pressure dependence of all features of interest has been observed. The mechanical stability criteria has been checked in terms of elastic constants and pressure. Upon compression, InSb is found to become more resistant to the deflection or deformation. An increase of micro hardness of the material in question has been seen when pressure is applied suggesting thus that InSb under pressure is a useful material in the fabrication of devices. The behavior of the Kleinman internal parameter with pressure indicates that InSb exhibits strong resistance to changes in its bond length. [ABSTRACT FROM AUTHOR]

The luminescent oxide glasses with composition 50P 2 O 5 - 30ZnO- 20CdO (PZCdO pure) and 50P 2 O 5 - 30ZnO- 20CdO- 30000 ppm Tm 2 O 3 (PZCdO:Tm) were synthesized by using melt- quenching technique. The optical energy gap and Urbach energy of these glasses were calculated by using UV–Vis–NIR spectroscopy. Judd– Ofelt parameters Ω 2 , Ω 4 and Ω 6 , branching ratio, β R , and radiative lifetimes, τ R , of Tm 3+ ions doped PZCdO glasses were estimated. The spectroscopic results showed that the present glasses has the effective emission cross section bandwidth (Δλ eff = 90 nm) and high stimulated emission cross-section (σ em = 1.5 × 10 −21 cm 2 ). The blue up conversion emissions sharp band at 458 nm corresponding to transition 1 D 2 → 3 F 6 and weak emission band in NIR region assigned to 1 G 4 → 3 H 4 for the glasses PZCdO:Tm with UV- excited at 354 nm region were obtained. From result we can suggest that the present glasses can be used for blue light emitting diodes BLED chip. [ABSTRACT FROM AUTHOR]

Herein, we report the growth, characterization and field emission application of well-crystalline 6-fold symmetrical hierarchical ZnO nanostructures grown on silicon substrate by thermal evaporation process. The detailed morphological characterizations revealed that the prepared material possess six-fold structures in which ZnO nanoneedles are symmetrically grown on each facets of core hexagonal ZnO nanorods in such a manner that they made beautiful 6-fold symmetrical hierarchical structure. The detailed structural studies confirmed that the grown hierarchical structures possess well-crystallinity with wurtzite hexagonal phase. The room-temperature photoluminescence (PL) spectrum exhibited a strong UV emission confirming good optical properties. The Raman-scattering revealed the wurtzite hexagonal phase for as-grown hierarchical structures. The field emission properties of the 6-fold symmetrical hierarchical ZnO nanostructures were tested and a turn-on voltage equal to 2.8 kV, corresponds to emission current of 65 nA, was observed. A threshold voltage of 4.6 kV with a maximum emission current of about 9.36 µA was also recorded. A high emission current stability profile over a period of ~7000 s was noted for the fabricated FE device. [ABSTRACT FROM AUTHOR]

Herein, we report the facile growth of ZnO nanoflowers composed of nanorods on silicon substrate by non-catalytic thermal evaporation process. The grown nanoflowers were examined in terms of their morphological, structural, optical and field emission properties. The detailed characterizations revealed that the nanoflowers are grown in high density, possessing well-crystallinity and exhibiting wurtzite hexagonal phase. The Raman-scattering spectrum shows a sharp optical-phonon E 2 mode at 437 cm −1 which confirmed the wurtzite hexagonal phase for the grown nanoflowers. The room-temperature PL spectrum depict a strong ultraviolet emission at 381 nm, revealed good optical properties for the ZnO nanoflowers. The field emission studies revealed that a turn-on field for the ZnO nanoflowers based field emission device was 4.3 V/μm and the emission current density reached to 0.075 mA/cm 2 at an applied electric field of 7.2 V/μm and exhibit no saturation. The field enhancement factor ‘ β ’ for the fabricated device was estimated from the F-N plot and found to be ~2.75×10 3 . Finally, systematic time-dependent experiments were performed to determine the growth process for the formation of ZnO nanoflowers composed of nanorods. [ABSTRACT FROM AUTHOR]

This work has been performed to estimate the effect of BaO doping on the structural and optical properties of sodium borate–based glass, which contains an equal concentrations of both the cerium and copper oxides. The traditional fast cooling method was followed to obtain the desired glasses, by adding different content of BaO to the components of the cerium/copper sodium borate glass. The X-ray patterns as well as SEM/EDX imaging reflected the amorphous nature of the prepared solids, while FTIR spectra revealed the existence of the two basic structural groups of borate glass (BO3 and BO4) for the both Ba-free and Ba-doped samples. When the BaO content was raised, FTIR also revealed the presence of the distinct structural group of cerium tetrahedral CeO4. BaO content showed an impact on the values of the bulk density, the direct/indirect energy gaps, and the optical conductivity, where when BaO was increased the values of both density and optical conductivity decreased while those of the energy gaps increased. The Drude-Lorentz model has been used to simulate the optical conductivities of the studied glasses. The optical conductivity reached its maximum value at 1430 THz in the high-energy region. The simulation process is supported by the terahertz band communications parameters matched with the previous studies. The obtained materials can be used in the terahertz band. The intensity of ESR spectra increased when BaO increased, which means an increase in the paramagnetic centers throughout the host BaO-rich glassy sample. [ABSTRACT FROM AUTHOR]

The pressure dependence of optical constants and exciton properties in ZnTe with zinc-blende structure has been investigated. The calculations are carried out using a pseudopotential approach. At zero pressure, our results are accordant with those published in the literature. Upon compression, all features being studied in this work show generally a monotonic and non-linear behavior. The information derived from this study could be useful for the use of the material of interest in optoelectronic, microelectronic and photovoltaic applications. [ABSTRACT FROM AUTHOR]

We report here the structural, FTIR, optical and dielectric properties of Zn1-xAlxO with x = 0.00 ≤ x ≤ 0.20)). The samples are synthesized by the solid state reaction method and the phase purity, structural morphology, and absorption spectra are examined by XRD, SEM, and FTIR techniques. The optical and dielectric measurements are obtained by a double beam spectrophotometer and an impedance analyzer. The wurtzite structure is confirmed for all samples, and the lattice parameters, crystallite diameter, and porosity are decreased by Al, whereas the Debye temperature and elastic modulus are increased. The residual stress is compressive for ZnO, but it is changed to tensile for the doped samples. Two different values of energy gap (Egh and Egl) are apparent for each sample. The Egh and Egl are, respectively, 3.60, 3.56, 3.43, 3.53, 3.68 eV and 3.02, 2.95, 2.85, 2.92, 3.07 eV for all samples such that ΔE = (Egh – Egl) ~ 0.60. The residual dielectric lattice constant is decreased by increasing x to 0.10, followed by a sharp increase at x = 0.20, while the opposite behavior is obtained for (N/m*). The dielectric constant and ac conductivity are slightly increased as x increases to 0.025, followed by a sharp increase with more increase of x to 0.20. The conduction is electronic for pure and x = 0.025 samples, but it changes to hole with increasing x to 0.20. The binding energy was decreased as x increased to 0.20, but there is no exact trend for the hopping distance and density of localized states against x. The F-factor for solar cell design was increased as x increased to 0.10, but it is almost constant at x = 0.20. The Cole–Cole plot is a straight line for x = 0.00, a semicircle arc for x = 0.025, and a complete semicircle for x ≥ 0.05. The impedance resistance of grain and grain boundaries decreases as x increases to 0.20. These outcomes indicate that the addition of Al to ZnO shifts the mechanical, optical, and dielectric medium to higher values, which is strongly recommended for the design of optoelectronic and solar cell instruments. [ABSTRACT FROM AUTHOR]

• Positron behavior in indirect band-gap semiconductors under pressure. • Elastic constants versus pressure in AlSb. • Electron and positron energy levels in AlSb at various pressures. • Hydrostatic pressure effect on positron affinity in AlSb. • Positron diffusion constant in AlSb under compression. • The information gathered from the present investigation is very useful in slow-positron-beam experiments and positron annihilation in indirect band-gap semiconductors. The positron characteristics such as chemical potential, affinity, effective mass and diffusion constant in AlSb indirect band-gap semiconductor are investigated at zero pressure and under compression. The calculations are mainly performed in the framework of a pseudopotential approach. We follow the evolution of all features of interest as a function of pressure. Our results show that upon compression, the positron becomes thermalized in a time longer than that at zero pressure. Moreover, its affinity decreases with raising pressure indicating that it annihilates differently from zero pressure. A close inspection of the positron diffusion constant suggests that the positron diffuses better under applied pressure. The present contribution can be a useful support for studying positron annihilation in indirect band gap semiconducting materials. [ABSTRACT FROM AUTHOR]

The optical limiting characteristics of the Cobalt (Co) metal-doped PVA films have been measured using two laser beams at 632.8 nm and 533 nm wavelength. Different weight percentages of Co metal were stirred with PVA solution to get polymeric composite films by casting method. The crystallinity degree and the intermolecular structure of the samples have been tested by X-ray diffraction (XRD) and FT-IR spectroscopy. The semi-crystalline order of the pure PVA reduced with more adding of Co-metal due to the interaction of dopant ions with one pair of electrons of oxygen in the hydroxyl (-OH) group of the matrix as confirmed by the FTIR spectra. Moreover, the formation of the Co clusters with different size and non-uniform distribution on the composite films surface morphology has been presented by SEM. The thermal stability was carried out via DTA (Differential thermal analysis) and revealed that the Co-metal/PVA composites are more stable than PVA pure. The doped PVA film absorption increased, while the absorption edge shifted from 5.33 eV to 4.61 eV with the Co metal ratio due to the formation of localized states in the forbidden gap during the interaction between the –OH groups in the matrix of PVA and Co-metals. Also, the Urbach energy of the present films has been estimated. The direct electronic transitions have been observed only at doping ≥7.5%, as established from the results obtained from Tauc's model and optical dielectric loss. The film with ten wt.% of Co-metal shows a small energy gap and significant absorption properties. Thus, the present polymeric composite films with high Co-metal concentrations are suitable for laser attenuation and optical limiting in photonic devices. • Laser optical limiting characteristics of Co-metal doped PVA films have been studied. • Co-transition metal enhanced the absorption of PVA films and decreased its transmission. • The absorption edge shift to lower energy due to the ascending of the Co-transition metal doping ratio in PVA. • The type of electronic transition has been determined from Tauc's model and quantum theory. [ABSTRACT FROM AUTHOR]

Collective effects and some response characteristics such as piezoelectric stress and strain constants, Fröhlich coupling parameter, optical electronegativity and exciton properties of CdSe x Te 1-x common-cation ternary alloys have been investigated. The calculations are carried out using a pseudopotential approach under a modified virtual crystal approximation that takes into account the alloy disorder effect, combined with the Adachi model. Generally, a good accord is obtained between our results and those available in the literature. The composition dependence of the features of interest shows that the Fröhlich coupling parameter remains almost constant, the piezoelectric properties vary almost linearly and the optical properties exhibit a non-linear behavior. [ABSTRACT FROM AUTHOR]

In this paper we present optical and exciton properties of Zn x Cd 1-x S using a pseudopotential approach within an improved virtual crystal approximation which includes the alloy disorder effect. Features such as, refractive index, dielectric constants, exciton reduced mass, exciton binding energy and exciton Bohr radius have been investigated and their dependence on composition has been examined and discussed. All features of interest are found to vary monotonically and non-linearly with the Zn content. The results obtained in the present study may provide useful information for use of this alloy system in various device applications from visible to ultraviolet light. [ABSTRACT FROM AUTHOR]

The curcuminoid class of organic compounds is very versatile which possesses applications over vast fields of science and technology. In the present investigation, we systematically designed six curcuminoid (Crmd) derivatives with symmetric and asymmetric structures, which are named as Crmd-1 to Crmd-6. We used 2,2-difluoro-4,6-divinyl-dioxaborinine moiety as a linker to design symmetric and asymmetric donor π-conjugation and acceptor configurations. Triphenylamine and triphenylborane are used as donor and acceptors which are intrinsically donor and acceptors owing to the presence of vacant p-orbital in boron and lone pair of electrons in nitrogen atoms, respectively. Density functional theory (DFT) is applied using M06/6-311G* method to calculate linear polarizability (α), and second hyperpolarizability (γ). The value of isotropic linear polarizability (αiso) and anisotropic linear polarizability (αiso) are 125.3 × 10–24 esu and 148.1 × 10–24 esu for Crmd-6, respectively. By comparative analysis, it is observed that the highest value of γ amplitude is calculated to be 6472.3 × 10–36 esu for Crmd-6. The robust increase in non-linear optical (NLO) polarizability is observed due to the asymmetric intramolecular charge transfer (ICT) and better D-π-A configuration in Crmd-6. Time dependent DFT calculations are performed to observe the origin of third-order NLO polarizabilities. Furthermore, frontier molecular orbitals, electron density difference, molecular electrostatic potential diagrams, and transition density matrix analysis demonstrate enhanced charge redistribution from the donor to the acceptor fragments. The use of modern computational tools highlights an effective ICT, which leads stronger third-order NLO response properties in designed curcuminoid derivatives. [ABSTRACT FROM AUTHOR]

Using ab initio total energy based on density functional theory calculations, the phase transition, band structure, optical spectra and magnetic moment of MnO in the rock salt structure have been investigated. All studied quantities are discussed with respect to their dependence on pressure. Our results show a phase transition of MnO from the semiconducting rock salt to a metallic CsCl at pressure of 67.12 GPa. Applied pressure is found to play an important role in the modulation of optical properties. The optical absorption coefficient indicates that MnO more readily absorb photons under high pressure. The total magnetic moment for rock salt MnO at zero pressure agrees reasonably well with those reported in the literature and decreases monotonously with increasing pressure. [ABSTRACT FROM AUTHOR]

Tellurite glasses with a composition of 76TeO2-10ZnO-9PbO-1.0PbF2-3.0Nb2O5-1.0 x in mol% modified with different rare earth oxides (where x= La2O3, Gd2O3, Er2O3, and Ho2O3). The magnetic properties such as; Faraday effect and the Verdet constant at the intensity of the laser beam (λ = 632 nm) of the present glasses were measured. The glass contains La2O3 has the highest value of Verdet constant, (V = 0.102min/G.cm) otherwise the sample has Ho2O3 has the lowest value of Verdet constant (V = 0.069 min/G.cm). It means that V-value strongly depends on the polarizability of rare earth. An optical isolator is a unidirectional light gate, which can prevent the back reflection of light into lasers or optical amplifiers and reduce signal instability and noise. Finally, the structure of prepared glasses was investigated by Raman spectra. [ABSTRACT FROM AUTHOR]

A series of new thiazoline derivatives were synthesized. Structure analyses were accomplished employing 1H-NMR, 13C-NMR, X-ray and MS techniques. The in vitro antitumor activities were assessed against human hepatocellular carcinoma (HepG-2) and colorectal carcinoma (HCT-116) cell lines. The results revealed that the thiazolines 5b and 2c exhibited significant activity against the two cell lines. The in vitro antimicrobial screening showed that the thiazolines 2c, 5b and 5d showed promising inhibition activity against Salmonella sp. Additionally, the inhibition activity of thiazolines 2e and 5b against Escherichia coli was comparable to that of the reference compound gentamycin. [ABSTRACT FROM AUTHOR]

Composite films with vital multifunctional properties for optoelectronic and varistor applications were prepared via casting procedures. Herein, the present novel composites are based on semi-crystalline polyvinyl alcohol, PVAL, mixed with different contents of Ruthenium-metal. The structure of the films has been fully identified through Fourier Transform (FT-IR), diffraction analysis of X-ray (XRD), and microscopy of scanning electron (SEM). They confirm significant interactions between Ru-metal and PVAL, which leads to a decrease in polymer crystallinity. Ru-metal's impact on the optical performance has been studied using spectroscopy of UV–Vis–NIR, whereas the applicability of these films for varistor devices was investigated by measuring the electrical conductivity and I–V curves. The crystallite length (D), the spacing of interplanar (d), dislocation density (δ), internal strain (ε), and separation of interchain (R) parameters were calculated from the measurement of XRD. The active absorption band in FTIR spectra shows a significant interaction of Ru-metal with the PVAL via OH groups. The cluster of metal on the composite surface increases with the doping concentration, as illustrated via SEM. Optical bandgaps (Egi & Egd) are estimated from Tauc and absorption fitting (ASF) are nearly equal and reduced with ruthenium addition. Limiting optical absorption (LOA) performance tested using two laser sources showing the reduction of optical transmission via high doping concentration films. With rising Ru-metal content and frequency, the dielectric and AC conductivity tends to be enhanced. Also, the I-V characteristic was improved, and the conductivity follows the fitting of Jonscher. The collected result reflects the consideration of flexible Ru/PVAL as a promising polymeric film in varistor, micro-optics, optical fibers, and CUT-OFF laser applications. [ABSTRACT FROM AUTHOR]

New polymeric nanocomposite films of PVOH (polyvinyl alcohol) embedded with Bi-nanoparticles have been described by scanning electron microscopy and x-ray diffractometer. From UV-visible spectroscopy, the absorption edge shifts to the higher wavelengths direction (redshift). Tauc's model for optical bandgap transitions demonstrates that the direct and indirect values are reduced with the increase of Bi percentage in the PVOH matrix. In contrast, Urbach energy (tail bandwidth), extinction coefficient, refractive index, and optical conductivity are increased. These indicate the rise of the charge transfer among the Bi nanoparticles and the macromolecules of the matrix. Using Wemple–Di Domenico model for single-oscillator, we calculated the nonlinear optical refractive index and susceptibility. The optical limiting characteristic has been tested via a green laser source of wavelength 533 nm. The present results offer new materials for optical Cut-Off and nonlinear optical applications. [ABSTRACT FROM AUTHOR]

As a new 2D material, MXenes are anticipated to impact future energy storage and conversion technologies significantly. This article reviews recent progress in MXene-based nanomaterials for oxygen evolution reaction (OER). In addition, the method of synthesizing these materials as an OER and essential concepts to motivate future research were highlighted, and obstacles to the sustainable development of this field were presented. A-layer selective etching with aqueous solutions containing fluoride ions is now the preferred method for developing MXenes. Until now, the difficulty in synthesizing a wide variety of MXenes has been attributed to Al high reactivity with fluoride-based aqueous media, which is particularly potent for those produced from MAX-phase precursors of containing Al. • Recent progress in MXene-based nanomaterials for oxygen evolution reaction is assessed. • Method of synthesizing these materials as an OER and essential concepts were highlighted. • Obstacles to the sustainable development of this field were presented. [ABSTRACT FROM AUTHOR]

Thiophene is a core structure in many marketed drugs, such as Duloxetine, Tiotropium, Raloxifene, Dorzolamide, Tioconazole, Citizolam, Sertaconazole Nitrate and Benocyclidine. Thiophene derivatives are reported to have several types of pharmacological and biological activities. The synthesis of new thiophene derivatives is important to pharmaceutical research, because of their diverse pharmacological activities. The reaction of ethyl 3-oxobutanoate with carbon disulfide and chloroacetone in the presence of K2CO3 affords the unexpected thiophene derivative 7. Furthermore, refluxing compound 7 with dimethylformamide-dimethylacetal (DMF-DMA) in DMF affords the enaminone derivative 8. The structures of these newly synthesized compounds were confirmed by means of various spectroscopic techniques, such as IR, MS, and NMR, as well as by X-ray diffraction. In addition, B3LYP/6-311G(d, p) basis sets were employed to optimize the molecular geometry of the two thiophene derivatives. Furthermore, natural atomic charges and frontier molecular orbital analyses were performed. Hirshfeld analysis of the molecular packing showed that H—H, O—H, C—H, and S—H are the most common intermolecular interactions in both compounds. Further analysis suggests that the O—H interactions are the most significant of these in compounds 7 and 8. [ABSTRACT FROM AUTHOR]

We report here the effects of argon annealing on the structural and critical parameters of oxygenated copper oxide system with different oxygen purities (Hp 99.99% and Lp 93%). It is found that the structure of the samples maintains orthorhombic single phase independent of both oxygen purity and annealing. The mean field temperature Tcmf is increased by annealing from 92 to 94 K for Lp sample, but it is decreased from 93 to 90 K for Hp sample. Similar behavior is obtained for crossover temperatures To. Further, the coherence length and interlayer coupling are decreased by annealing for both samples, and their values are higher for Lp samples than those for Hp samples. The excess conductivity analysis reveals two different exponents corresponding to crossover temperature for each plot: The first exponent is obtained in the normal field region at a temperature range of ln ε (0 ≥ ln ε ≥ − 2), and their values are 1.50, 1.53, 1.62 and 1.47 for both samples, in which the order parameter dimensionality (OPD) is one dimension, while the second exponent is obtained in the mean field region at a temperature range of ln ε (− 2 ≥ ln ε ≥ − 4), and their values are 0.39, 0.59, 0.56 and 0.41 for both samples, in which the OPD is 3D. Although the critical temperatures are decreased by annealing for both samples, the critical fields and critical currents are increased by annealing for both samples and their values are higher for Hp sample than those for Lp sample. Our results are discussed in terms of oxygen vacancies and concentration of carriers which are produced by annealing and oxygen purity for the considered samples. [ABSTRACT FROM AUTHOR]

Using highly economical and scalable nebulizer-aided spray pyrolysis approach, a high-quality terbium (Tb) doped vanadium pentoxide (V 2 O 5) thin film-based optical sensor was developed. To investigate the effects of various terbium doping concentrations on its growth and optoelectronic features, the structural properties as well as its elemental composition, surface morphology, photoluminescence, optical, and current-voltage (I-V) characteristics were examined. An orthorhombic structure with orientation along the (010) plane was found to be existing in the X-ray diffraction pattern of Tb-doped V 2 O 5 thin films with increase in the crystallite size upto 3 % Tb-doped V 2 O 5 films. The prevalence of dense nanorods is observed in all the films while analyzing their micrograph from a field emission scanning electron microscope. Also it is noted that the addition of 3 % Tb dopants increases UV absorption by lowering its energy gap from 2.43 to 2.37 eV. A strong green emission peak at 530 nm and weak UV bands were noted in the PL spectrum due to higher crystalline quality, free from defects and native flaws for the 3% Tb-doped V 2 O 5. Terbium-doped V 2 O 5 films exhibited elevated UV photo response and photoelectric properties than their pristine form. Among various doping concentrations, 3 % terbium in V 2 O 5 thin film exhibited a maximum response (4.72 × 10−1 A/W), detectivity (7.82 × 1010 Jones), external quantum efficiency (110 %), and high photo-switching characteristics. This study confirms the optimal 3 % Tb dopant concentration plays a significant role in enhancing the UV–visible photo-sensing behavior of the V 2 O 5 thin films. The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study. • Spray pyrolysis development of V 2 O 5 :Tb(0–5 wt%) films is reported for photosensing. • Structural and elemental analyses of the prepared samples confirm the structure of V 2 O 5. • Emission spectra reveal a single, strong green emission at a wavelength of 535 nm. • R, D* and EQE were found to be 4.72 × 10−1 A/W, 7.82 × 1010 J, 110 % for 3 wt% Tb:V 2 O 5 film. • The rise/decay time of the developed photodetector was found to be very quick. [ABSTRACT FROM AUTHOR]

Mn3O4 (MO) nanoparticles have drawn a lot of attention due to their use in batteries, ion exchange, sensors, and catalysts in various oxidation states. Here, prior to developing new hybrid freestanding films with different MO nanoparticle concentrations (0, 0.037, 0.37, and 3.7 wt%), it was essential to first manage the electrical and optical properties of the PVA/PVP blend. Several methods, including high-resolution transmission electron microscopy, Atomic force microscope, FTIR, and XRD, were accustomed to verifying the emergence of the polymeric nanocomposite (PNC) films. The correlation between both the optical and dielectric properties of the films and the bandgap was altered using the doping ratio. In terms of its optical properties, MO is observed to have a significant impact on pure PVA/PVP, including the indirect optical energy gap, the localized state's order, the absorption coefficient, and the response of optical conductivity. Hervé–Vandamme, Moss, Singh-Kumar, and Ravindra are a few models that have studied the connection between energy gaps and refractive index. Moreover, PVA/PVP/xMn3O4 polymer nanocomposite samples with varied MO levels were examined for their linear together with nonlinear optical properties (NLOP). The exclusion of both ordinary and laser light is studied in the PVA/PVP enriched MO (NPs) samples that were created. Moreover, there are sharp decreases in the laser transmitted power from 315.88 to 13.6 mW for the pure blend to 0.135 and 0.00039 for PNC/3.75Mn3O4 nano-composition using a laser source of 623.8 and 533 nm, respectively. Thus PNC/3.75Mn3O4 sample is recognized as a good prospect for relatively inexpensive optical limiting and laser filter innovation. [ABSTRACT FROM AUTHOR]

For energy‐efficient and high‐power illumination systems, phosphor materials have attracted huge research attention over the recent decades. Herein, applying the first‐principles method, we investigate and predict the optoelectronic and structural properties of light‐harvesting phosphors Z2SiF6 (Z = K, Li, Na, Rb) as promising candidates for weight‐light‐emitting diodes w‐LEDs. The calculated direct energy band gaps are of order 1.56, 1.461, 1.479, and 1.585 eV for Z2SiF6 (Z = K, Li, Na, Rb), respectively, thus rendering the compound's semiconducting nature suitable for optoelectronic applications. Calculated structural properties show that Rb2SiF6 is the most stable compound among Z2SiF6 (Z = K, Li, Na, Rb). The optical properties in the energy range of 0–14 eV have been investigated using the well‐known (GGA) formulism available in the literature. Studied compounds are active optical materials as the value of their refractive index nω is between 1.0 and 2.0. Based on investigated optical parameters, we can say that Z2SiF6 (Z = K, Li, Na, Rb) are potential candidates for optoelectronic device applications like white LEDs (w‐LEDs). Thermodynamic parameters of Z2SiF6 (Z = K, Li, Na, Rb) are provided to establish the thermodynamic stability of these compounds. [ABSTRACT FROM AUTHOR]

A facile molecular wedging method is used to exfoliate graphite flakes into graphene sheets, with concurrent functionalization to form pyrene-1-boronic acid functionalized graphene (PBA/G). Different techniques are used to characterize the prepared materials such as field emission scanning electron microscope, energy dispersive X-ray analyzer, Raman, Fourier transformed infrared spectroscopy and fluorescence spectroscopy to evaluate their structural and morphological characteristics. The intercalation of PBA into graphite sheets, followed by exfoliation can be observed under the electron microscope. Elemental analyses show that the PBA acts more than intercalant, it is functionalized onto the graphene sheets upon exfoliation to form PBA/G. Raman analysis indicates PBA/G has a lower number of graphene layers as a result of successful exfoliation by PBA. Electrochemical impedance studies show that the PBA/G possesses high affinity for dopamine through the diol groups interaction, which renders it to have enhanced detection for dopamine. Image 10 • Pyrene-1-boronic acid functionalized graphene is prepared using facile molecular wedging method. • Pyrene-1-boronic acid intercalates and functionalizes onto graphene (PBA/G). • PBA/G possesses a high affinity for dopamine detection. • Electrochemical impedance analyses show enhanced dopamine detection for PBA/G electrode. [ABSTRACT FROM AUTHOR]

Zinc oxide-doped tin dioxide (ZnO–SnO2) nanomaterials were prepared by a sol–gel method with and without different amounts (0.5, 1.0 and 2.0 g) of polyethylene glycol (PEG). The prepared nanocomposites were characterized for structural, surface and optical properties. The effect of a PEG on the prepared ZnO–SnO2 nanocomposites was investigated. The photocatalytic activities of the synthesized nanocomposites were evaluated by methylene blue dye degradation under UV illumination. The ZnO–SnO2 nanocomposites prepared with 2.0 g of PEG showed the highest degradation efficiency of 87.30%, suggesting that adding PEG enhances the photocatalytic performance of ZnO–SnO2 nanocomposites due to increased inhibition of e−/h+ pair recombination and efficient generation of superoxide radical anions and hydroxyl radicals. [ABSTRACT FROM AUTHOR]

Abstract The mechanical of the tricalcium phosphate matrix sintered with different amounts of the magnesium oxide have been investigated. The tricalcium phosphate - magnesium oxide composites were characterized by using the mechanical properties such as rupture strength, Vickers hardness and elastic modulus. The effects of the sintering process on the structural changes of the composites were investigated. At 1300 °C, the highest performance was obtained for the tricalcium phosphate containing 5 wt% MgO. The maximum mechanical strength and Young's modulus of the composites reached 9 MPa and 38 GPa, respectively. The result can be explained by the formation of both, liquid phase, which helps to fill the pores in the microstructure, and a new phase relative to the calcium magnesium phosphate. At 1400 °C and beyond 5 wt% MgO, the performances of the composites are hindered by the intragranular porosity formation and by the exaggerated grain growth. The addition of the magnesium oxide to the tricalcium phosphate matrix promotes the reduction of the wear rate and the friction coefficient. The composites performances are close to the enamel. Highlights • We measure the mechanical and tribological properties of bioceramics. • We characterize the effect of MgO on the performances of the tricalcium phosphate. • MgO increases the performances of the tricalcium phosphate. [ABSTRACT FROM AUTHOR]

Abstract In this work, the flake size-dependent adsorption kinetics of graphene oxide (GO) aerogel is studied. GO in different flake sizes are produced by sonication prior to the preparation of aerogel through freeze-dry method. The structural characterizations reveal that GO aerogel with smaller flake size possesses higher surface area and higher intensity of edge-plane oxygen functionalities. These provide more adsorption sites and active sites for heavy metal ions adsorption. Adsorption study reveals the higher Fe3+ ions adsorption capacity as well as uptake rate on GO aerogel with smaller flake size. The adsorption kinetic obeys the pseudo-second-order kinetic model which indicates the chemisorption is the rate-determining step. Adsorption isotherms of GO aerogel on Fe3+ ions show highest Langmuir adsorption capacity of 133.3 mg/g and render it to be a potential material for heavy metal ions removal in wastewater treatment. Graphical abstract Unlabelled Image Highlights • GO aerogel was produced in different flake sizes. • GO aerogel provides adsorption sites and active sites for Fe3+ adsorption. • GO aerogel in smaller flakes size shows higher Fe3+ adsorption and uptake rate. • Chemisorption is the rate-determining step according to pseudo-second-order kinetic. • GO aerogel shows a high adsorption capacity of 133.3 mg/g. [ABSTRACT FROM AUTHOR]

This study presents the electrochemical studies of activated carbon prepared from palm kernel shell (ACPKS), with CaO impregnation. The CaO is obtained from chicken eggshell waste to produce CaO/ACPKS, which shows highly porous honeycomb structure with homogeneous distribution of CaO nanoparticles (30-50 nm in size). The prepared materials are evaluated as supercapacitor electrodes by testing their electrochemical characteristics. A high specific capacitance value of 222 F g−1 at 0.025 A g−1 is obtained for CaO/ACPKS, which is around three times higher than that for ACPKS (76 F g−1). In addition, electrochemical impedance data show lower impedance for CaO/ACPKS. Lastly, a practical symmetrical supercapacitor is fabricated by CaO/ACPKS and its performance is discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Development of In 2 S 3 :Er (0 to 5 wt%) thin films using spray pyrolysis technique for photosensing applications is reported. • In 2 S 3 :Er (2 wt%) thin film possess minimum bandgap compared to other films. • Photocurrent, responsivity (R), detectivity (D*) and external quantum efficiency (EQE) were measured to be 1.05 AW−1, 12.1 × 1010 Jones and 246 %, respectively for 2 wt% Er:In 2 S 3 film. • The rise/fall time of the detector is noticed to be 1.7/4.4, 1.7/3.8, 1.5/2.7, 2.1/3.6, 2.3/4.4 and 2.4/4.5 s for 0, 1, 2, 3, 4 and 5 % Er:In 2 S 3 films, respectively. • These outcomes indicates that the In 2 S 3 films developed with 2 wt% of Er doping will be highly useful in photosensor-based optoelectronic devices. In this article, rare earth Erbium (Er) doped In 2 S 3 by varying the Er concentration from 0 to 5 % was synthesized using the nebuliser spray pyrolysis method. The influence of Er doping in In 2 S 3 host in its crystalline, morphological, and optical studies were carried out. The X-ray diffraction (XRD) studies showed that the In 2 S 3 :Er thin films have a face centered cubic structure, its prominent peak belongs to (4 0 0) plane, the crystallite size changes with increasing Er dopant concentration and attained maximum for the 2% Er-doped In 2 S 3 thin film. The morphological analysis of the thin film surface was carried out using field emission electron microscope (FESEM) measurement and found that the samples possess uniform grains without any surface defects. The Photoluminescence spectroscopy showed that three luminescence peaks were observed at 420, 480 and 525 nm which is due to the excitonic recombination and generation of vacant sites of In and S ions in the host material. From the photoluminescence (PL) spectra, the 2% Er-doped In 2 S 3 thin film exhibited higher luminescence intensity than other prepared samples in this present work. The UV–Vis spectroscopy depicted that the optical energy gap decreases up to 2 % and started to increase for further Er doping. The photo-sensing characteristics of the prepared samples were done and their significant parameters were measured. The determined photo sensing parameters such as responsivity (R), detectivity (D*), and external quantum efficiency (EQE) were found to be 1.05 AW−1, 12.1 × 1010 Jones and 246% respectively. These study results proved that the 2% Er doped In 2 S 3 thin film sample could be an excellent photosensor based optoelectronic devices. [ABSTRACT FROM AUTHOR]