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One of the major concerns that receive global attention is the presence of organic pollutants (dyes, pharmaceuticals, pesticides, phenolic compounds, heavy metals, and so on), originating from various industries, in wastewater and water resources. Rhodamine B is widely used in the dyeing of paints, plastics, textiles, and other fabrics, as well as biological products. It is highly persistent, toxic, and carcinogenic to organisms and humans when directly released into the water supply. To avoid this hazard, several studies have been conducted in an attempt to remove Rhodamine B from wastewater. Metal oxide semiconducting materials have gained great interest because of their ability to decompose organic pollutants from wastewater. TiO2 is one of the most effective photocatalysts with a broad range of applications. Several attempts have been made to improve its photocatalytic activity. Accordingly, we have prepared in this work a series of cerium (Ce) and samarium (Sm) co-doped TiO2 nanoparticles (x = 0.00, 0.25, 0.50, 1.00, and 2.00%) using a sol–gel auto-combustion approach. The influence of Ce–Sm concentrations on the structural, morphology, electronic, and optical properties, as well as the photocatalytic activity, was investigated. Structure and elemental mapping analyses proved the presence of Ce and Sm in the compositions as well as the development of the TiO2 anatase phase with a tetragonal structure and crystallite size of 15.1–17.8 nm. Morphological observations confirmed the creation of spherical nanoparticles (NPs). The examination of the electronic structure properties using density functional theory (DFT) calculations and of the optical properties using a UV/Vis diffuse spectrophotometer showed a reduction in the bandgap energy upon Ce–Sm co-doping. The photocatalytic activity of the synthesized products was assessed on the degradation of Rhodamine B dye, and it was found that all Ce–Sm co-doped TiO2 nanoparticles have better photocatalytic activities than pristine TiO2 nanoparticles. Among all of the prepared nanoparticles, the sample with x = 0.50% demonstrated the best photocatalytic activity, with a degradation efficiency of 98% within 30 min and a reaction rate constant of about 0.0616 min−1. h+ and •O2− were determined to be the most important active species in the photocatalytic degradation process. Besides the high photocatalytic degradation efficiency, these photocatalysts are highly stable and could be easily recovered and reused, which indicates their potential for practical applications in the future.

This study is focused mainly on impact of irrigation water quality in cultivated soil on distribution of essentials nutrients (Al, Mg, Ca, Fe, S, Si, Na, P, and K) and relatively toxic metals (As, Ba, Cr, Cu, Ti, Sn, Mn, Ni, and Zn) using an elegant Laser induced breakdown spectroscopy (LIBS) technique. A pulsed Nd:YAG laser operating at 1064 nm in conjunction with suitable detector was applied to record soil emission spectra. The abundance of these elements were evaluated via standard calibration curve Laser Induced Breakdown Spectroscopy (CC-LIBS) and calibration free Laser Induced Breakdown Spectroscopy (CF-LIBS) approaches. Quantitative analyses were accomplished under conjecture of local thermodynamic equilibrium (L.T.E) and optically thin plasma. The average electron temperatures were estimated by Boltzmann plot method for cultivated soil samples in 7800 to 9300 K range. The electron number density was ~ 1.11 × 1017 cm − 3 to 1.60 × 1017 cm − 3. Prior to application on soil samples, the experimental setup was optimized at the following parameters: pulsed energy = 60 mJpulse-1, sample to lens distance of 9.0 cm, and the gate delay of 3.5 μs. It is noteworthy that nutritional elements content of cultivated soils were found strongly dependent upon the irrigation water quality. The cultivated soil from industrial area was found rich of toxins while the cultivated land using tube well water contains toxins in least amount. Our LIBS findings were also validated by comparing its results with contents measured using a standard inductively coupled plasma optical emission spectroscopy (ICP-OES) method and both were found in excellent agreement. The present study could be highly beneficial for agricultural applications and for farmers to produce safe food products and higher crops yield.

ZnFe2O4 (ZFO) NPs (nanoparticles), Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 (CNGaGdFO) NPs and hard-soft spinel ferrite (H/S) (CNGaGdFO)x/(ZFO)y (x:y = 1:1, 1:2, 1:3, 2:1, 3:1 and 4:1) NCs (nanocomposites) were synthesized via a one-pot sol–gel auto combustion route. X-ray powder diffraction (XRD) analyses confirmed the purity of ZFO NPs, CNGaGdFO NPs and H/S (H/S) (CNGaGdFO)x/(ZFO)y (x:y = 1:1, 1:2, 1:3, 2:1, 3:1 and 4:1) (absence of any second phase). The crystallite size of NCs was between 39 and 52 nm. The cubic morphology was observed for ZFO NPs, CNGaGdFO NPs and all H/S NCs by the help of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. Energy dispersive X-Ray analysis (EDX) also confirmed the chemical formula of all the NC samples. Electrical and dielectric properties of ZFO NPs, CNGaGdFO NPs and H/S NCs were explored with an impedance analyzer with f ? 3.0 MHz, where f stands for frequency, and within the temperature range between 20 and 120 °C. Electric and dielectric parameters such as AC conductivity as well as DC conductivity, activation energy, dielectric constant, dielectric loss in addition to the dissipation parameter relevant to the electrical energy due to different physical processes were measured for each of the given compositional ratios. The AC conductivity was found to follow the frequency-dependent power law in general, being mainly reliant on the compositional ratios and the measured temperatures especially at lower frequencies. This study has shown that CoNiGaGdFeO-ZnFe2O4 H/S NCs carry out conduction mechanisms, which can be predominantly credited to grain–grain boundaries for various compositional ratios. The dielectric constant of (CNGaGdFO)x/(ZFO)y (x:y = 1:1, 1:2, 1:3, 2:1, 3:1 and 4:1) H/S NCs indicates common dielectric behaviours with frequency, largely dependent on compositional rates of the hard to soft spinel ferrites. It is observed that hard ferrite is dominant in the formation of the semicircles, and the diameter of the semicircles shows a drop as the temperature rises, suggesting a temperature-dependent relaxation mechanism. Consequently, the observed variation of the studied dielectric parameters with frequency can be explained by the conduction mechanism in most composition ratios of hard to soft spinel ferrites, which can be explained by a phenomenological method with Koop's model. © 2021 The Author(s)

Quantitative and qualitative analyze of toxic and nutritional elements existing in different kinds of black tea (Camellia Sinensis) leaves available in Pakistan was conducted with calibration free/laser-induced breakdown spectroscopy (CF/LIBS). A Q-switched Nd:YAG laser employed to create micro-plasma on the tea sample surfaces. The quantitative analysis accomplished by studying the spectral emissions of plasma using a dedicated spectrometer. Iron, magnesium, sodium, potassium, calcium, aluminum, and zinc were measured as essential nutrients, while chromium, copper, manganese, nickel, and lead as toxic metals. In order to get precise and reliable analysis, the LIBS setup was optimized by performing various parametric dependence studies. The Boltzmann plot method was adopted for calculation the plasma temperature its average values are between ~ 7500 and 9000 K for all kinds of tea leaves. To find out the electron number density (Ne), the Stark broadened line of atmospheric hydrogen pea (Hα) was chosen and was found between 1.13 × 1017 cm−3 and 1.61 × 1017 cm−3. The laser-generated micro-plasma was optically thin, and the effect of self-absorption in spectral emission lines was found negligible. The LIBS results were verified by means of inductively coupled plasma/atomic emission spectroscopy (ICP/AES). The findings obtained using LIBS and ICP techniques displayed an excellent agreement which exhibit that LIBS is very good to for spectro-chemical analysis of food products.

Laser-induced breakdown spectroscopy (LIBS) was employed to determine Cr, Ni, and Zn in Neem-based beauty soaps and Neem leaves. The measurements were accomplished by attaining the optically thin p...

A novel family of visible-light-sensitive photocatalysts, bismuth oxyhalide solid solutions (BiOBrnI1-n, n = 0–1), was synthesized by a nonaqueous solvothermal method. The bismuth oxyhalides crystallized in individually separated platelets which aggregated into microspheres, allowing for efficient light capture. By increasing the Br/I ratio, the band gap of BiOBrnI1-n could be tuned from 1.95–2.95 eV. The material with the composition BiOBr0.75I0.25 exhibited the best photoactivity. It catalysed the degradation of p-cresol under visible light at a rate 31-times that of pure BiOBr and 1.7-times that of BiOI. BiOBr0.75I0.25 proved to be a versatile photocatalyst for the degradation of a wide range of substituted alkyl phenols and endocrine disrupting chemicals (EDCs). Total organic carbon in the water was reduced to 10–33 % at > 99 % degradation efficiency. The excellent performance was attributed to a matching bandgap, balance between light absorption and redox potential, and efficient charge separation. Recyclability testing showed that BiOBr0.75I0.25 maintained its high activity even after three cycles of p-cresol photodegradation.

Zirconium–Titanium–Thallium Ternary Oxide Ceramic (0.5ZrO2-(0.5-x)TiO2-xTl2O3 (x = 0, 0.05, 0.15, 0.2 and 0.25 mol %) was synthesized via solid-state reaction. Advanced analytical technique like Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-Ray diffraction (XRD) were used to study the microstructure and the solubility of thallium oxide in the ZrO2/TiO2 mixture. The diffuse reflectance and photoluminescence techniques were employed to investigate the optical properties of the prepared alloys for various Tl2O3 mol% concentrations. In addition, the mass attenuation coefficient (MAC) for the synthesized ceramic samples was measured experimentally and compared with XCOM data. Our experimental values were in good agreement with XCOM data. Various shielding parameters for gamma-rays, neutron, proton, and alpha particles were evaluated using XCOM, Phy-X, and SRIM programs. The Tl2O3 content linearly affects the gamma-rays shielding parameters, while the Tl2O3 content has an inverse relationship with neutron and charged particle shielding parameters. This study proved that our Zirconium–Titanium–Thallium Ternary Oxide Ceramic samples can be applied as ionizing radiation shielding material very well.

Laser induced breakdown spectroscopy (LIBS) was applied for analyzing the impact of earthquake on the elemental distribution of the soil, collected from the earthquake-stricken locations near Eurasian and Indian Tectonic Plates in the Kashmir Valley. The quantitative elemental analysis was carried out using an advanced calibration-free LIBS technique, assuming the establishment of optically thin plasma under the local thermodynamic equilibrium conditions. The results exhibited that the soil has nearly random concentration distribution of metallic elements such as Al, Na, and K, nonmetallic element P, micronutrients such as Fe and Si and secondary macronutrients such as Ca, S, and Mg, in and around the radius of 9 km from the epicenter of the earthquake. It is exhibited that the concentration of carbon in particular is the highest near the epicenter and declines systematically with the outward radial distance. The quantitative analysis by LIBS was confirmed and counter verified through the inductively coupled plasma atomic emission spectroscopy (ICP–OES), and results achieved by both the techniques (LIBS and ICP–OES) are in good agreement.

Surface faradaic process can bring about storage (pseudocapacitive) mechanism that store much more energy than conventional electric double-layer capacitors (ELDCs) quite rapidly. Many transition metal oxides possess pseudocapacitor properties, but only few are capable of providing a high power capability because of their low intrinsic conductivities. Here we demonstrate that lead- and bismuth-based hybrid halide perovskites, anchored with carbon nanodots, can operate at rates exceeding those of ELDCs and provide higher area normalized and volumetric capacitances than standalone halide perovskites and carbon dots. We report carbon nanodots in methyl ammonium bismuth iodide (CNDs/MBI) and methyl ammonium lead iodide (CNDs/MPI) hybrid electrodes, designed to facilitate electron transfer and cation accessibility to faradaic active sites. Devices based on CNDs/MBI and CNDs/MPI electrodes are able delivered up to 550 Fg−1 and 402 Fg-1, with corresponding energy densities of 76.5 Wh/kg and 55.8 Wh/kg at scan rates of 0.01 V−1. Deconvolution of the cyclic voltanogramm also provide insight to fraction of charge storage due to surface- and diffusion-controlled process.

We report a novel, green, scalable technique to synthesize binder-free, high-purity conductive composite comprising activated carbon (AC), manganese dioxide nanorods (MnO2), and reduced graphene oxide sheets (rGO) for flexible supercapacitors with outstanding electrochemical performance. UV pulsed laser irradiation of GO-based composite dispersion (AC/GO or MnO2@AC/GO) in ethanol aqueous medium was used to induce a photocatalytic reduction of GO and simultaneous anchor AC particles or AC loaded MnO2 nanorods (MnO2@AC) on the reduced GO sheets (rGO) at room temperature and atmospheric pressure. rGO sheets serve as a large surface area, conductive binder to enhance the ion adsorption, electrical conductivity, and mechanical flexibility of supercapacitor electrodes. This laser-induced photocatalytic reduction method was used to prepare two different rGO-based colloidal composites AC/rGO (CG) and MnO2@AC/rGO (MCG). The prepared rGO-based colloidal composites were used to fabricate symmetric supercapacitors (CG//CG and MCG//MCG) and asymmetric supercapacitors (MCG//CG) in which MCG is the positive electrode and CG is the negative one. All prepared rGO-based supercapacitors demonstrated significant improvement in their electrochemical performance compared with rGO-free AC based supercapacitors. The enhancement in the electrochemical properties of rGO-based supercapacitors could be attributed to the intrinsic characteristics of rGO, such as high surface area, excellent electrical conductivity, and super mechanical flexibility. Our approach is a one-step, scalable, cost-effective synthesis technique to produce all binder-free AC/rGO based composites for flexible energy-storage devices.

Ceramic-polymeric 3C–silicon carbide-graphitic carbon nitride (3C–SiC@g-C3N4) nanocomposites were synthesized by decorating cubic phased, ceramic 3C-Silicon carbide (3C–SiC) on the framework of the nanosheets of metal free polymeric graphitic carbon nitride (g-C3N4) by single step pulsed laser ablation in liquid (PLAL) method. Morphological, structural, elemental and optical characterizations of the synthesized 3C–SiC@g-C3N4 nanocomposites were carried out. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM) studies confirm the perfect anchoring of 3C–SiC on g-C3N4 nanosheets in 3C–SiC@g-C3N4 nanocomposites synthesized by PLAL method. Ultra-violet diffuse reflectance spectra (UV-DRS) of 3C–SiC@g-C3N4 indicated the enhancement of visible light absorption and also the narrowing down of band gap energy in 3C–SiC@g-C3N4 nanocomposites, as a result of the anchoring of 3C–SiC on g-C3N4. Also we noticed the decrease of photoluminescence (PL) emission intensities in the PL spectra of 3C–SiC@g-C3N4 with respect to pure g-C3N4, which indicates the reduced photo-induced charge recombination by the presence of 3C–SiC content on g-C3N4 nanosheets. In the application side, PLAL synthesized 3C–SiC@g-C3N4 nanocomposites exhibited enhanced visible light driven photocatalytic degradation of methylene blue dye in water, improved antibacterial activity against Pseudomonas aeruginosa (gram-negative) and Staphylococcus aureus (gram-positive) bacteria, and also served as better inhibiting agent for biofilm formation, compared to pure g-C3N4 nanosheets. It is quite obvious from our studies that this ceramic-polymeric nanocomposite, 3C–SiC@g-C3N4 has the potential application for antibacterial and anti-biofilm activities in addition to its remarkable photocatalytic performance.

The Ceylon cinnamon is known for its unique aroma and medicinal benefits, and it has been used in indigenous medicines for thousands of years. The elements present in cinnamon can be nutritional as well pharmacologically mediate therapeutic properties to cure diseases. In this study, the elemental composition of cinnamon was evaluated using two advanced elemental analysis techniques: laser induced breakdown spectroscopy (LIBS) and X-ray photoelectron spectroscopy (XPS). The results of both the studies mutually substantiated the predominant level of some vital nutrients like potassium and calcium, besides other elements. Initially the LIBS system was experimentally optimized, specifically for the elemental analysis of cinnamon, and also the key plasma parameters like plasma temperature, and electron number density were measured to confirm the establishment of local thermodynamic equilibrium in laser induced plasma in cinnamon. Our LIBS system detected the presence of many vital nutrients like Na, K, Fe, Cd, Mg, Mn, Ni, Ba, Si, F, P, Ca, O, K, and S in cinnamon. In addition of LIBS, the XPS elemental study revealed the presence of Ca, O, K, and S, which further reiterated the predominance of these elements in cinnamon samples. The comparative analysis of these two techniques indicates that apparently LIBS is far more sensitive than XPS to detect trace level of many elements. Among the nutritional elements, the presence of potassium in cinnamon explains its medicinal use for hypertension under diuretic treatment. The results presented in this paper may be instrumental for the development of various cinnamon based herbal medications.

Quantitative investigation of essential and trace heavy elements present in health-beneficial dry fruits (Pistachio, Almonds, Black walnut, White walnut, and Cashew) was investigated using Laser Induced Breakdown Spectroscopy. For an accurate elemental exposure using LIBS technique, the local thermo-dynamical equilibrium of the laser induced plasma was established and verified using McWhirter criterion based on the electron number density in the plasma. Earlier to engage, our LIBS detector was optimized. For quantification of elements, standard calibration curves (CC)-LIBS method was applied. Using our LIBS system, the nutritional elements such as Al, Mg, Ca, Fe, K, Zn, and Na and toxins like Pb, Cr, and Cu were detected in dry fruits. The elemental quantification of dry fruit contents were validated using standard (ICP-AES) method and the relative accuracy of our experimental setup in comparison to ICP approach was in the ranging from 0.1 to 0.3 at 2.5-% error confidence.

Effects of laser irradiation on the thermal properties and morphological structure of starch, polyvinyl alcohol (PVA) and their blends were studied. Laser irradiation has an insignificant effect on...

Effective remediation of produced water requires separating crude oil-water mixture and removing the dissolved organic pollutants. Membranes with selective wettability for water over oil enable the gravity-driven separation of an oil-water mixture by allowing water to permeate through while repelling oil. However, these membranes are often limited by their inability to remove the dissolved organic pollutants. In this work, a membrane with in-air superhydrophilic and underwater superoleophobic wettability is fabricated by thermal annealing of a stainless steel mesh. The resulting membrane possesses a hierarchical surface texture covered with a photocatalytic oxide layer composed of iron oxide and chromium oxide. The membrane exhibits chemical and mechanical robustness, which makes it suitable for remediation of crude oil and water mixture. Further, after being fouled by crude oil, the membrane can recover its inherent water-rich permeate flux upon visible light irradiation. Finally, the membrane demonstrates that it can separate surfactant-stabilized crude oil-in-water emulsion under gravity and decontaminate water-rich permeate by photocatalytic degradation of dissolved organic pollutants upon continuous irradiation of visible light.

In this study, a new configuration of dye sensitized solar cells (DSSCs), in which a TiO2 photoanode is co-sensitized by N719 organic dye and CdSe quantum dots (CdSe-QDs), was fabricated. The photovoltaic performance of the cell, which was co-sensitized with an optimum concentration of CdSe-QDs, was found to be superior to that of the cell with a photoanode sensitized using N719 dye. The superior performance can be attributed to the energy-compatible band structures of the N719 dye molecule and the CdSe-QDs, selective transfer of a significant number of photogenerated electrons from the energy state of the dye molecule to the conduction band (CB) of CdSe-QDs, and improved absorbance of the CdSe-QDs in the visible-light spectrum. This initial inflow of electrons to the dye was found to enrich the subsequent dye-mediated electron transfer to TiO2, thus contributing to the enhanced photocurrent in the DSSC. The novel material implemented in this study was based on CdSe-QDs, which were used as a co-sensitizer in the photoanode of the DSSC synthesized by pulsed laser ablation in liquid (PLAL). Morphological, structural, elemental, optical and electrochemical characterizations of the photoanodic materials were conducted; and the photovoltaic characteristics of the fabricated cell were determined. The photovoltaic conversion efficiency of the cell co-sensitized by CdSe-QDs at a certain concentration (1 mg/15 ml of ethanol) and N719 dye was found to be 7.09%, which corresponds to a 37% enhancement of the photovoltaic efficiency when compared with the cell sensitized only by the N719 dye.

This work reports the pulsed laser deposition of n-type selenium (Se) doped bismuth telluride (Bi2Te2.7Se0.3) and n-type bismuth telluride (Bi2Te3) nanostructures under varying substrate temperatures. The influence of the substrate temperature during deposition on the structural, morphological and thermoelectric properties for each phase was investigated. Density functional theory (DFT) simulations were employed to study the electronic structures of the unit-cells of the compounds as well as their corresponding partial and total densities of states. Surface and structural characterization results revealed highly crystalline nanostructures with abundant grain boundaries. Systematic comparative analysis to determine the effect of Se inclusion into the Bi2Te3 matrix on the thermoelectric properties is highlighted. The dependence of the thermoelectric figure of merit (ZT) of the nanostructures on the substrate temperatures during deposition was demonstrated. The remarkable room temperature thermoelectric power factor (PF) of 2765 μW/mK2 and 3179 μW/mK2 for pure and Se-doped Bi2Te3 compounds respectively, signifies their potential of being useful in cooling and power generation purposes. The room temperature ZT values of the Se-doped Bi2Te3 was found to be 0.92, about 30% enhancement as compared with the pure phase, which evidently results from the suppressed thermal conductivity in the doped species caused by phonon scattering at the interfaces.

In this work, a novel method was developed to synthesize visible light-responsive ZnO/ZnSe photocatalysts, using rapid, simple Pulsed Laser Ablation of Solids in Liquids (PLASL) method. Using this method, we synthesized high-purity ZnO/ZnSe hybrid nanostructures with an optimum weight ratio of 10:4, which exhibited better photocatalytic activity. The addition of ZnSe on the ZnO semiconductor surface improved the light absorption of the composites and simultaneously decreased the photoluminescence emission intensity, which is an indicator of the inhibition of the electron-hole recombination rate. The nanostructured composites synthesized using the PLASL method were applied for photo-electrochemical water splitting and photo-degradation studies. The synthesized ZnO/ZnSe hybrid nanocomposites exhibited excellent visible-light-driven photocatalytic activity, which is highly desirable for water decontamination and photo-electrochemical water oxidation. This work, therefore, empirically demonstrates how this simple, cost-effective laser-based technique can be employed to rapidly synthesize high-purity, visible-light responsive photocatalysts expanding the potential for future solar energy conversion technologies.

Hard/soft ferrite nanocomposites (NCs) (SrHF)/xMCD (1.0 ≤ x ≤ 3.0) consisting of SrFe12O19 HF (SrHF) and Mg0.5Cd0.5Dy0.03Fe1.97O4 (MCD) were obtained via one-pot sol-gel auto-combustion approach. The measurements of impedance spectroscopy are presented for new fractional (SrHF)/xMCD (1.0 ≤ x ≤ 3.0) hard/soft ferrite NCs, including reference soft and hard ferrites. The electrical conductivity and activation energies of fractional composite ferrites are observed to be regulated depending on the fractional ratios. It has been established that the temperature dependence of the DC conductivity obeys the Arrhenius law, especially for the fractional composite ferrites. To control the conduction mechanism, the conductivity and its frequency power exponent are evaluated based on a small polaron tunnelling model. Magnetic properties were verified by applying a DC magnetic field up to ±70 kOe at 300 and 10 K. Magnetization data significantly decreased with increasing fraction of MCD in NCs. These results showed that exchange-coupling was not achieved in these NCs by one-pot approach. Additionally, anticandidal activity of the synthesized nanomaterials was studied by evaluating the colony forming unit (CFU). The obtained results are significant for potential applications in the field of biomedicine.

Pliable supercapacitor, yielding specific capacitance (Cs) and energy density as high as 348 F g−1 and 48.3 Wh Kg−1 respectively was fabricated using modified activated carbon electrodes. The nanospheres of activated carbon (AC) were anchored on the nanoplates of boron nitride (BN) by employing the facile technique of pulsed laser ablation in liquid (PLAL) using 532 nm focused laser beam. Four different variants of electrode materials were synthesized by varying the weight percentage (1%, 3%, 5% and 10%) of BN in AC in the PLAL precursor solution. The morphological characteristics, the elemental composition and the structural analysis of the synthesized electrode materials were studied respectively by FESEM, XPS and XRD. The morphological studies indicated that the PLAL synthesis of the electrode materials resulted in proper intercalation of carbon nanospheres into BN nanoplates, which resulted in the observed enhanced performance of the fabricated supercapacitor. Four supercapacitors in this work were fabricated using the four variants of synthesized electrode materials in conjunction with gel polymer electrolyte (GPE). GPE are well known for their non-corrosive nature and best sealing ability to avoid any leakage that results in increasing the cycle life of the device. The performance of the fabricated supercapacitors was evaluated using cyclic voltammetry (CV), galvanostatic charge discharge (GCD) measurement and electrochemical impedance spectroscopy (EIS). The results indicate that the supercapacitor fabricated using 3% BN in AC as electrode material manifested the best specific capacitance and energy density. Also it was found that the supercapacitor maintained 85% of its initial capacitance even after 5000 charge/discharge cycles.

Efficient photonic characterization is imperative for efficient harvesting and storing of photon energy. In that regard, two architectures of perovskite photodiodes, where distinct heterojunction l...

The photo catalytic degradation, a proven chemical process used for the decontamination of organic/inorganic pollutants and microorganisms in water was implemented. In this work for the selective killing of cervical cancer cells (HeLa cells) by using nano-composite of ZnO (Zinc Oxcide), WO3 (tungsten oxide) and (n-WO3/ZnO) as a photo-catalyst under the irradiation of visible light. All the three nanostructured semiconducting materials (WO3, ZnO and n-WO3/ZnO) were synthesized by facile chemical precipitation method and their morphological and optical characterization studies were carried out to elucidate the observed enhancement in the photo-catalytic killing of HeLa cancer cells with n-WO3/ZnO as a photo-catalyst. After 60 min of photo-catalytic reaction with n-WO3/ZnO as a photo-catalyst, a survival viability of HeLa cancer cells as low as 15% was achieved (nearly 85% of killing), as compared to 65% of HeLa cancer cell survival viability (nearly 35% of killing) with individual use of WO3 and ZnO as photo-catalysts under the same irradiation and experimental conditions. This improved photo-catalytic killing of HeLa cancer cells using n-WO3/ZnO in the visible spectral region is attributed to the enhanced visible light absorption and reduced electron hole recombination, characteristically brought about in the n-WO3/ZnO composite material. As photo-catalytic killing of the cancer cells can be selective, localized and reasonably efficient, in principle, this method can be considered as a non-invasive targeted treatment option for killing any type of cancer cells. HeLa cells, in particular are the cervical cancer cell and the tumors in and around cervix, containing HeLa cells can be non-surgically accessed and photo-catalytically treated with appropriate photo-catalyst and light source.

Our main interest in this work is in the synthesis and improvement of the physical properties of TiO2-based nanocomposites modified by coupling to Zn2SiO4:Mn (ZS:M) nanoparticles. The micro-structural characterizations carried out by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques of various TiO2-ZS:M (Ti-ZS:M) samples at different temperatures revealed the formation of the anatase phase. The optical properties of TiO2 modified by ZS:M nanoparticles shows a shift in absorption band toward UV region reflecting a significant an increase in the energy band gap for anatase phase at 3.36 eV, which is larger than the 3.06 eV found for the Dugussa P25 TiO2. In this work, the influence of the annealing temperature on the microstructural, physico-chemical characteristics of the different samples is presented and their correlation with their photoluminescence in the visible spectral region has been investigated.

Thermoelectric (TE) materials have increasingly entranced the attention of researchers globally, with a view to providing alternative routes to clean energy. This work reports the first thermal conductivity measurement on pulsed laser deposited Bi2Se2.7Te0.3 (BTS) thin films by a non-contact and optical-based method. Structural characterization revealed well-crystalline films whereas the scanning electron microscope images show abundant grains typical of the BTS nanostructures. A highly stoichiometric composition was observed under energy dispersive spectroscopy. The film's first-order temperature coefficient was estimated by varying the substrate temperature using advanced Raman spectrometer equipped with an inbuilt Linkam stage. The linear dependence of the E2g phonon mode on temperature and excitation laser power was harnessed to estimate the value of the suspended film's room temperature thermal conductivity. The first-order temperature coefficient was measured to be 0.0359 c m − 1 K − 1 . The low thermal conductivity measured at room temperature ( κ ~ 1.12 Wm − 1 K − 1 ) is comparable to previously reported values obtained using different conventional techniques. This work proved the potential of Raman spectroscopy to estimate the thermal conductivity as an excellent alternative tool to the existing expensive and laborious techniques. In addition, this work demonstrated that BTS is an excellent material for thermoelectric energy harvesting.

Nanomaterials 11(9), 2461 (2021). doi:10.3390/nano11092461 special issue: "Special Issue "Oxide Magnetics" / Special Issue Editor Prof. Dr. Sergei Trukhanov, Geues Editor", Published by MDPI, Basel

In this study, the samples of the ZnFe2O4 (ZFO) spinel ferrites nanoparticles (SFNPs), Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 (CNGaGdFO) SFNPs and (Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4)x/(ZnFe2O4)y (x:y = 1:1, 1:2, 1:3, 2:1, 3:1 and 4:1) (CNGaGdFO)x/(ZFO)y spinel ferrite nanocomposites (NC) have been synthesized by both sol-gel and Green pulsed laser ablation in liquid (PLAL) approaches. All products were characterized by X-ray powder diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), elemental mappings and energy dispersive X-ray spectroscopy (EDX). It was objected to tune the magnetic properties of a soft spinel ferrite material with a softer one by mixing them with different fractions. Some key findings are as follows. M-H investigations revealed the exhibition of ferrimagnetic phases for all synthesized samples (except ZnFe2O4) that were synthesized by sol-gel or PLAL methods at both 300 K and 10 K. ZnFe2O4 ferrite NPs exhibits almost paramagnetic feature at 300 K and glass-like phase at very low temperatures below 19.23 K. At RT analyses, maximum saturation magnetization (MS) of 66.53 emu/g belongs to nanocomposite samples that was synthesized by sol-gel method and x:y ratio of 1:3. At 10 K analyses, MS,max = 118.71 emu/g belongs to same nanocomposite samples with ratio of 1:3. Maximum coercivities are 625 Oe belonging to CNGaGdFO and 3564 Oe belonging to NC sample that was obtained by sol-gel route having the 3:1 ratio. Squareness ratio (SQRs = Mr/MS) of NC sample (sol-gel, 4:1 ratio) is 0.371 as maximum and other samples have much lower values until a minimum of 0.121 (laser, 3:1) assign the multi-domain wall structure for all samples at 300 K. At 10 K data, just CNGaGdFO has 0.495 SQR value assigning single domain nature. The maximum values of effective crystal anisotropy constant (Keff) are 5.92 × 104 Erg/g and 2.4 × 105 Erg/g belonging to CNGaGdFO at 300 K and 10 K, respectively. Further, this sample has an internal anisotropy field Ha of 1953 Oe as largest at 300 K. At 10 K another sample (sol-gel, 3:1 ratio) has Ha,max of 11138 Oe which can also be classified as a soft magnetic material similar to other samples. Briefly, most magnetic parameters of NCs that were synthesized by sol-gel route are stronger than magnetic parameters of the NCs that were synthesized by PLAL at both temperatures. Some NC samples were observed to have stronger magnetic data as compared to magnetic parameters of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 NPs at 10 K.

In this work, the synthesis of tungsten oxide/reduced graphene oxide (WO3-rGO) nanocomposite, using a simple method of pulsed laser ablation in liquids (PLAL) is reported. The pulsed laser beam of 355 nm wavelength carries out two simultaneous processes: the reduction of graphene oxide and at the same time the anchoring of nanostructured WO3 on reduced graphene oxide. In the photo-catalytic application, WO3-rGO shows much better visible light absorption and less photo-generated charge recombination than pure WO3, as indicated by optical absorption and photoluminescence spectra. These improved features in WO3-rGO significantly enhanced the photo-catalytic decontamination of methylene blue (MB) dye in the water, compared to the use of pure WO3 as a photocatalyst. A Poly 2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS) based electrolyte together with the high electrical conductance and porosity of rGO which were produced after anchoring WO3 on the graphene oxide, were harnessed for the energy storage application using this material for a supercapacitor. The specific capacitance for WO3-rGO based device is achieved to be 577 F g−1 measured by the galvanostatic charge-discharge (GCD) method. Also, at a power density of 1000 W kg−1, the as-synthesized WO3-rGO demonstrated a large energy density value of 76.3 Wh Kg−1 that is much larger than obtained, using WO3 alone. Besides these photocatalytic and energy storage performance evaluation of WO3-rGO, the optical, morphological and elemental characteristics of synthesized WO3-rGO were also investigated to study the improved performance of the nanocomposite in these two applications.

1,5-naphthyridine-based conjugated polymers (P1 and P2) were synthesized and extensively characterized by 1H NMR, thermogravimetric analysis (TGA), FT-IR. These polymers were employed as co-sensitizers in DSSCs sensitized with Ru (II) based N3 dye. In comparison to the N3 sensitized device, the P1 and P2 co-sensitized solar cells demonstrated enhanced open circuit voltage, (VOC) of 825 and 788 mV and better fill factor (FF) of 59 and 58%, respectively. The co-sensitization of P1 and P2 with N3 increased the overall efficiencies to 5.88% and 6.21%, respectively, as compared to 5.58% for N3 sensitizer alone. The fabricated device based on N3 co-sensitized with P2 displayed higher charge recombination resistances as compared to the devices based on N3 alone or N3 co-sensitized with P1. The conjugated polymers are believed to enhance light harvesting ability and reduce the charged recombination in the co-sensitized solar cells.