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Due to the characteristic emission of phosphors, phosphor-converted LEDs have been employed to provide the requisite light sources for indoor plant growth in the optical agricultural industry. Herein, we prepared a series of Mn2+ co-doped NaSrB5O9:Dy3+ phosphors via a solid-state reaction method. These phosphors have significant three-band emissions at 467 nm (blue region), 606 nm (orange region), and 765 nm (far-red region), ascribed to the 4F9/2-6H15/2 and 4F9/2-6H13/2 transitions of the Dy3+ ions and the 4T1g(G)-6A1g(S) spin-forbidden transition of the Mn2+ ions, respectively, when excited by light of 376 nm (near-UV region). The co-dopant in the host material facilitates tunable photoluminescence (PL) due to energy transfer from the Dy3+ ions to the Mn2+ ions. The three emission peaks from the prepared phosphors well match with the absorption spectra of the photosynthesis pigments of plants, chlorophyll and phytochrome, which can absorb blue (400–500 nm), orange-red (550–700 nm), and infrared (IR) radiation, indicating that these phosphors have potential applications in the fabrication of plant-growth LEDs. Prior to the PL studies, the structure of the phosphors was determined by X-ray diffraction, refined by Rietveld method and chemically quantified by X-ray photoelectron spectroscopy.

Barium yttrium phosphate (BYP) phosphor doped with trivalent praseodymium ions (BaY(1-x) (PO4 )3 :Pr3+ (x = 0, 0.01, 0.05, 0.1, 0.15, and 0.2 wt%) was synthesized using a high temperature solid-state reaction method. Structural properties were analyzed through X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. XRD patterns confirmed the structure of the synthesized phosphor and average crystalline size was estimated (approximately 63.8 A). Vibrational functional groups were identified using FTIR spectroscopy. The emission spectrum was recorded under an 444 nm excitation wavelength, which showed various emission transitions of Pr3+ ions. Commission Internationale de l'eclairage coordinates, colour purity, and colour correlated temperature values were calculated for the BYP:Pr3+ phosphors and these coordinate values fell in the yellow region of the visible spectrum.

In this study, metal-organic-framework (MOF) derived porous NiO hollow spheres and flowers were obtained using facile solvothermal synthesis and heat treatment. After pyrolyzing, the flower like and hollow spherical like morphology of NiO nanoparticles was successfully inherited from the initial MOF-based templates. The electrochemical studies demonstrated that the porous NiO hallow spheres unveiled a better supercapacitive performance (specific capacitance (Cs) = 1058 F g−1 at current density (j) = 2 A g−1) and oxygen evolution reaction (OER) catalytic activity (overpotential (ɳ) = 323 mV) compared to porous NiO flowers (Cs = 857 F g−1 at j = 2 A g−1 and ɳ = 346 mV). Moreover, excellent capacity retention of over 93% was obtained in porous NiO-hs nanoparticles even after 5000 cycles. The fabricated NiO//Fe2O3 asymmetric supercapacitor delivered an energy density (E) of 35.75 W h Kg−1 under power density (P) of 780 W kg−1 and showed promising stability over 3000 cycles. Considering the ease of preparation and high catalytic activity and supercapacitive performance, these prous NiO hallow structures can be considered as a potential electrode material for next generation energy storage devices and OER catalysts.

Curcumin is a natural polyphenol obtained from Curcuma longa which has gained much attention in medical and scientific fields and is known for its wide range of therapeutic applications. But the natural herb mixtures with high subatomic sizes have low retention limits which does not permit the restorative medication to cross the lipid membranes, subsequently bringing about low bioavailability with confined proficiency. Nanobiotechnology has overcome the drawbacks of curcumin delivery to its targeted site through the use of antioxidant-rich, biodegradable SLNs as drug delivery vehicle with specificity and expanded bioavailability that will encourage the dynamic release of therapeutic ingredients into the body. Herein, optimized curcumin-loaded SLNs (CuSLNs) were developed. The morphological analysis of SEM has shown the average particle size was found to be in the range of 71–112 nm. The physicochemical characteristics of optimized CuSLNs were particle size of 106 nm, zeta potential of − 54 mV, polydispersity index of 0.429 which have confirmed the nanoparticle stability. The FTIR, DSC, and XRD results have suggested the lipids are compatible and confirmed the complete solubilization of curcumin in the lipid phase. Encapsulation efficiency and drug loading capacity of optimized formulation were 88.22 and 13.13, respectively. In vitro release studies have shown the controlled drug release rate of 88% compared with free curcumin and 81% of in vitro antioxidant activity which is compared with the ascorbic acid. The studies confirmed that the formulation of CuSLNs is a promising drug delivery system with controlled drug release, improved bioavailability with good stability.

Over recent decades, the conversion of energy and its storage have been in the lime light due to the depletion of fossil resources. The electrochemical energy storage devices like supercapacitors and batteries, and their materials and fabrication methods have been extensively evaluated, which is the best solution for the energy crisis. Herein, zinc cobaltite (ZnCo2O4; ZCO) nanostructures grown on nickel (Ni) foam by microwave-assisted solvothermal fabrication for hybrid supercapacitors are reported. Two different structures/samples, ZCO-15/Ni (nanoflowers) and ZCO-30/Ni (nanowires), were obtained by simply adjusting the reaction time. The electrochemical and physicochemical properties of the as-prepared samples were systematically determined. Particularly, ZCO-15/Ni exhibits excellent structural stability due to its dual morphologies: nanoflowers and nanopetals, and exhibits a large electroactive surface area (25.61 m2 g−1), pore diameter (48.38 nm), and robust adhesion to Ni foam, enabling ion and electron transport. ZCO-15/Ni foam electrode delivers an excellent specific capacity of 650.27 C g−1 at 0.5 A g−1 and admirable cyclic performance of 91% capacitance retention after 5000 cycles compared to ZCO-30/Ni electrode. The excellent electrochemical performance of ZCO makes them promising electrode materials for batteries, hybrid supercapacitors, and other alternative energy storage applications.

Environmental issues: global warming, organic pollution, CO2 emission, energy shortage, and fossil fuel depletion have become severe threats to the future development of humans. In this context, hydrogen production from water using solar light by photocatalytic/photoelectrochemical technologies, which results in zero CO2 emission, has received considerable attention due to the abundance of solar radiation and water. Herein, a single-step thermal decomposition procedure to produce carbon-doped SnO2 nanostructures (C–SnO2) for photocatalytic applications is proposed. The visible-light-driven photocatalytic performance of the as-prepared materials is evaluated by photocatalytic hydrogen generation experiments. The bandgaps of the photocatalysts are determined by ultraviolet–visible diffused reflectance spectroscopy. The crystallinity, morphological features (size and shape), and chemical composition and elemental oxidation states of the samples are investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The proposed simple thermal decomposition method has significant potential for producing nanostructures for metal-free photocatalysis.

Strategic way of regulating and changing the morphological structures of metal oxides always direct to be contributed with different electrochemical properties for redox reactions in energy storage systems. Here in, we have engineered the morphologically controlled zinc cobaltite and zinc oxide (ZnO/ZnCo2O4) composite via an in situ solvothermal route. By varying the reaction time of the solvothermal synthesis, the morphology of the composite has significantly been transformed from Chrysanthemum to Marigold -flower like ZnO/ZnCo2O4 composite. The morphological variations are identified by scanning electron microscopy (SEM) images. The two phases of composites are quantified by refinement of X-ray diffraction data and is endorsed by X-ray photoelectron spectroscopy. By using these two analyses, the non-stoichiometry of the elements (Zn, Co and O) have quantified. Two composites not only demonstrate different physico-chemical properties but also contribute different electrochemical properties. Low reaction time synthesized ZnO/ZnCo2O4 composite has shown higher specific capacitance than the higher reaction time synthesized composite. The ZnO/ZnCo2O4 composite indicates specific capacitance of 705.1 F g−1 (at 0.3 A g−1), which is due to the Co-rich, higher surface area and lower charge transfer resistance of the low reaction time synthesized composite against the counterpart.

Due to modernization and the scarcity of fossil fuel resources, energy demand is continuously increasing. In this regard, it is essential and necessary to create a renewable energy source that can meet future energy demands. Recently, the production of H2 by water splitting and removing pollutants from the water has been essential for issues of energy and environmental demands. Herein, g-C3N4 and Ag-g-C3N4 composite structures have been successfully fabricated by the ultrasonication method. The physio/photochemical properties of prepared g-C3N4 and Ag-g-C3N4 were examined with different analytical techniques such as FTIR, XRD, UV-DRS, SEM, TEM, PL, and XPS analyses. The silver quantum dots (QDS) anchored to g-C3N4 structures performed the profound photocatalytic activities of H2 production, dye degradation, and antimicrobial activity under visible-light irradiation. The Ag/g-C3N4 composite with an Ag loading of 0.02 mole has an optimum photoactivity at 335.40 μmol g−1 h−1, which is superior to other Ag loading g-C3N4 composites. The synthesized Ag/g-C3N4 nanoparticles showed potential microbial inhibition activity during the preliminary screening, and the inhibition zones were comparable to the commercial antibiotic chloramphenicol. The loading of Ag into g-C3N4 paves the suppression, recombination and transfer of photo-generated electron-hole pairs, leading to the enhancement of hydrogen production, the diminishment of pollutants in water under visible light irradiation, and antimicrobial activity against multidrug-resistant pathogens.

The present work reports on the highly efficient microwave assisted Suzuki coupling reaction for obtaining pyromellitic diimide based symmetrical small molecules with donor-acceptor-donor (D-A-D) configuration. Electron rich bithiophene is employed as a donor and alkyl substituted pyromellitic diimide units are explored as acceptors to get the desired small molecules. In order to study the relation between chemical structures and material properties, the prepared compounds were characterized in detail using absorption spectroscopy, cyclic voltammetry and thermograviometric analysis. The compounds exhibited good thermal stabilities with high decomposition temperature. Photophysical investigations of the newly synthesized pyromellitic diimide based small molecules, suggests these materials as potential candidates for organic electronic applications.

Currently, metallic nanoparticles possessing versatile heterogeneous catalytic functionality such as in hydrogenation, water splitting, hydrogen production and CO2 reduction for global pollution remediation have been paid great attentions due to their high chemical stability, superior activity and unique electrical and optical properties. However, the gradual degradation of their catalytic activity on multiple usage limits the monometallic nanoparticles to industrial applications. Herein, we fabricated the highly porous fenugreek polysaccharide assisted green synthesis of AuPd nanostructures for heterogeneous catalytic hydrogenation of the industrial usable highly toxic 4-nitrophenol to the medicinally useful 4-aminophenol. The aqueous method developed in the present work is environmentally friendly, simple and low-cost procedure. The fabricated bimetallic porous AuPd nanostructures characterized using SEM, TEM, UV-Vis, XRD, XPS and FTIR analysis. The catalytic activity of the synthesized nanostructures was studied for the heterogeneous hydrogenation of 4-nitrophenol to 4-aminophenol in presence of NaBH4, and the catalytic kinetic for the hydrogenation was analyzed via an UV-Vis spectrometer.

Presently, photocatalytic hydrogen generation from water splitting has attractive limelight research towards accomplish green globalization (zero CO2 emission) and considered as fuel source of the future due to their high energy content. Heterogeneous semiconductor/metal hybrid structures are receiving increased attention because of their advanced optical, electrical, and catalytic properties, which result from synergic effects. Herein, we developed an approach to fabricate interwoven Cu core nanowires (Cu NWs) decorated with different weight of ZnO nanorods (ZnO NRs) for photocatalytic applications. The bandgaps of the prepared hybrid structures were calculated by using UV–Vis spectra, their crystalline nature was examined with XRD, the morphology of nanostructures was studied by SEM, and their elemental composition and oxidation states were analyzed by XPS. Their photocatalytic activity was investigated for the production of hydrogen and dye (Rhodamine B) degradation. The Cu NW–ZnO NR hetero-assemblies were found to exhibit high photocatalytic properties, due to the synergetic effects of the unique semiconductor/metal heterojunction. The optimized CuZ2 composite exhibited 7.2 times H2-production and 6.2 times degradation of RhB greater than pure ZnO, respectively. Moreover, ZnO-nanorods can harvest solar light to generate photoelectrons, with subsequent electron transfer through the Cu NWs that might favor photocatalytic processes for many energy applications.

Herein, we report the synthesis of between SnO

Admirable studies have been established on the utilization of ligand-materials as bimetallic nanoparticles in the field of nanoscience and biotechnology. UV-Vis, XRD, HR-TEM, STEM-HAADF, EDS, FTIR, and DPPH analyses characterized the optical, structural, compositional morphological, and antioxidant properties of synthesized Cu-Ag nanostructures. The spectrum of UV-Vis exhibited absorption bands at 590 and 413 nm, which reflects the surface plasmon resonance of copper-silver nanostructures. Herein, our exploration of alkylamine stabilized copper/silver nanostructures while using hexadecylamine as capping material and their primary biomedical investigation on antimicrobial and antioxidant studies is reported. Cu-Ag bimetallic nanostructures were more effective against gram-negative bacteria E. coli and Klebsiella when compared to gram-positive bacteria. The antioxidant activity of Cu-Ag nanoparticles was comparable with Ascorbic acid.

With the rapid improvement of the global economy, the role of energy has become even more vital in the 21st century. In this regard, energy storage/conversion devices have become a major, worldwide research focus. In response to this, we have prepared two-dimensional (2D)-hierarchical sheet-like ZnCo2O4 microstructures for supercapacitor applications using a simple hydrothermal method. The 2D-hierarchical sheet-like morphologies with large surface area and smaller thickness enhanced the contact area of active material with the electrolyte, which increased the utilization rate. We investigated the electrochemical performance of sheet-like ZnCo2O4 microstructures while using Cyclic voltammetry (CV), Galvanostatic charge-discharge (GCD), and Electrochemical impedance spectroscopy (EIS) analysis. The electrochemical results demonstrated that the ZnCo2O4 electrode possesses 16.13 mF cm&minus, 2 of areal capacitance at 10 &micro, A cm&minus, 2 of current density and outstanding cycling performance (170% of capacitance is retained after 1000 cycles at 500 &micro, 2). The high areal capacitance and outstanding cycling performance due to the unique sheet-like morphology of the ZnCo2O4 electrode makes it an excellent candidate for supercapacitor applications.

Effectively electrode materials with optimized morphologies have exposed promising potential in continuous development of supercapacitor electrochemical performance over the past few years. Here, we prepared a novel design of CoMoO4 (CMO) microstructures through hydrothermal/solvothermal method and obtained two different morphologies: rod-like and pebbles-like, respectively. The phase purity, structural characteristics and chemical bonding of the samples were analysed by x-ray diffraction (XRD), Fourier Transform – Infrared (FT-IR) analyses. The morphological characteristics and composition of the samples were examined using Field emission-scanning electron microscopy (FE-SEM) and Energy dispersive x-ray spectroscopy (EDS) analyses respectively. The elemental composition and chemical states of the materials was further evaluated using XPS analysis. Electrochemical behaviour of the two different CMO microstructures was evaluated using Cyclic voltammetry (CV), Galvanostatic charge discharge (GCD), and Electrochemical impedance spectroscopy (EIS) analyses. A high areal capacitance of 1.57F cm−2 for R-CMO and 2.27F cm−2 for P-CMO at 1.5 A cm−2 and superior cycling stability of 90.49% for R- CMO, 85.95% for P-CMO was retained after 2,000 cycles. The unique hierarchical architectures with good structural and electrochemical properties of the materials creates new directions in the emerging field of energy storage applications.

Bimetallic nanomaterials have potential catalytic behaviour in hydrogenation, clean- energy production, catalysis and sensors due to their great stability, loftier activity unique electrical and chemical properties. Herein, we prepared Pd Ag bimetallic nanoparticles synthesized by using fungal extracted aqueous method, which is environmentally friendly cost-effective and simple procedure. The fabricated Pd Ag bimetallic nanoparticles were investigated by small area electron diffraction (SAED), transmission electron microscopy (TEM) X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) analysis. The electrochemical response of uric acid (UA) at Pd-Ag/CPE was studied in 0.1 M phosphate buffer solution at various pH, concentration and scan rate was investigated. Compare to Bare CPE, the Pd Ag nanocomposite modified electrode displayed the highest electrocatalytic activity for the detection of UA A linear response in the range of 4.69–273 nM with remarkable detection limit of 5.543 nM (CDL = 3ϭ/M) and quantification limit of 16.64 nM (CQL = 10ϭ/M) was obtained. The established nanoparticles (Pd Ag) embedded with carbon paste electrode (Pd-Ag/CPE) makes a good analytical tool for the sensing of UA in the biological and pharmaceutical samples.

A flexible transparent conductive electrode (TCE) with silver nanowires (AgNWs) is an essential component in flexible optoelectronic devices. Considerable efforts have been made to improve the transmittance and sheet resistance of AgNWs TCE for large area applications. However, long-term usages of AgNW TCEs are limited by their poor thermal and chemical stabilities under different atmospheric conditions. In this work, we propose to improve the opto-electrical properties by fabricating AgNWs layer on a metal mesh (MM) polyethyleneterephthalate (PET) substrate (AgNW/MM/PET). A bilayer structure of the AgNW/MM/PET was fabricated by bar coating, and it exhibited excellent opto-electrical properties with a transmittance of 90.3% and a sheet resistance of 0.745 Ω/sq. In addition, the fabricated AgNW/MM/PET showed more stable electrical performances than mono layer TCEs with AgNWs or metal mesh on PET under various environmental conditions, such as light, temperature, and humidity. The AgNW/MM/PET electrodes with excellent opto-electrical properties could be a possible replacement for indium tin oxide for large area flexible optoelectronic applications.

Researchers have tried to further advance the utilization of bimetallic nanoparticles in the field of catalysis due to their high stability, reusability, superior activity, and unique electronic and optical properties as compared with mono-metallic nanomaterials. Moreover, due to the lack of availability and economic viability of mono-metallic nanoparticles, it is necessary to produce highly active ultra-small bimetallic nanoparticles for industrial applications. Cu/Pd bimetallic nanoparticles are synthesized by using a mild hydrothermal one-pot method involving an aqueous solution with hexadecylamine as a capping agent for hydrogenation of aromatic nitro compounds. The synthesized bimetallic Cu/Pd nanoparticles form a cluster of 5 ± 3 nm bimetallic particles, and Cu/Pd clusters have been measured to perform the catalytic performance of hydrogenation of 4-nitrophenol, methylene blue, and methyl orange. Cu/Pd nanoparticles have been treated with lactic acid to remove the residual capping agent on the surface, which results in two times better catalytic relay effect between aromatic nitro compounds and NaBH4 in aqueous media than Cu/Pd without lactic acid treatment.

Over the past few decades, increasing attention has been focused on overcoming the scarcity of fresh water resources, with the rapid effluents of dyes from modern chemical industries causing issues in photosynthetic activity of aquatic organisms. In the process of recycling wastewater, the degradation of dye pollutants such as 4-nitrophenol, methylene blue, and methyl orange has become more crucial. Noble metal (silver, gold, palladium, and platinum) materials have significant potential applications in the areas of water purification, conversion of automobile exhaust emissions, and catalysis. Ultra-small alkylamine-capped palladium nanoparticles (APd NPs) with sizes below 10 nm are synthesized using hexadecylamine (HDA) as a stabilizing material, and HDA can prevent the irreversible aggregation of small-sized nanoparticles in solution-based reactions. The fabricated ultra-small APd NPs are investigated using UV–Vis, XRD, SEM, TEM, FTIR and TGA studies. In the presence of NaBH4 as a reducing agent, the APd NPs achieve high catalytic performance toward the degradation of dye pollutants such as 4-nitrophenol, methylene blue and methyl orange. Catalytic activity of alkylamine capped palladium nanoparticles for organic pollutant degradation.

Transparent conductive electrodes (TCEs) based on hybrid structures (silver nanowires) have been compressively reconnoitered in next-generation electronics such as flexible displays, artificial skins, smart windows, and sensors because of their admirable conductivity as well as flexibility, which make them favorable substitutes to replace ITO (indium tin oxide) as a transparent conductor. Nevertheless, silver-based TCEs grieve from poor stability because of the corrosion and oxidation of silver in electrolytes. To overcome these issues, a RGO (reduced graphene oxide) layer on silver was promoted to resolve the difficulties of corrosion and oxidation in the electrolyte. Moreover, we successfully designed and demonstrated low-voltage WO3-based electrochromic devices (ECDs) with fabricated hybrid TCEs. The hybrid electrodes with RGO/silver nanowires/metal grid/PET (RAM) electrode exhibited improvements in the switching stability and optoelectronic properties, such as the sheet resistance (0.714 ohm/sq) as we...

Noble-metal-free sustainable energy conservation has been attracting considerable attention for environmental protection and remediation. Herein, we present a low-temperature ( O, N–O, C–O–W, and C–O–W–N, which can alter the oxidation state of tungsten and boost-up the photocatalytic properties of O-g-C3N4/WO3. The optimized photocatalyst (O-g-CNW-4) produces higher H2 evaluation (15,142 μmol/g), which is 4.7 times higher than that produced by mechanical mixing samples. The prepared samples have highly porous structures with pore diameters of 20–30 nm. The C O, N–O, C–O–W, and C–O–W–N linkage vibrations of the prepared samples are analyzed, and their chemical confirmations and elemental oxidation states are verified. The oxygen-doped g-C3N4/WO3 porous structures exhibit large surface-areas with a huge quantity of active surface sites, band-structure modulation, and effective visible-light-harvesting of the photoinduced charge carriers, which is useful for enhancing photocatalytic H2 production.

Novel reduced graphene oxide-supported palladium nanoparticles (RGO-PN) were synthesized under ultrasonication, a method that utilizes Coleus amboinicus as a bio-reduction agent. Green synthesized RGO-PN nanoparticles with a crystallite size in the range of 40&ndash, 50 nm were confirmed in X-ray diffraction (XRD) spectra. RGO-PN show an absorption peak at 220 nm while reduced graphene oxide (RGO) shows its maximal absorbance at 210 nm. The scanning electron microscope image revealed that 40-nm-sized spherical-shaped palladium nanoparticles stick well to reduced graphene oxide sheets, which is consistent and correlated well with the XRD pattern. Moreover, a high-resolution morphological image of RGO-PN100 was obtained by TEM analysis, which shows the anchoring of palladium nanoparticles (PN) on RGO nanosheets. Green synthesized RGO-PN100 nanoparticles from Coleus amboinicus show better reduction kinetics for 4-nitrophenol at 40 min, suggesting that RGO-PN prepared from Coleus amboinicus serve as an excellent catalytic reducing agent. Furthermore, they show remarkable antibacterial activity against Escherichia coli (ATCC 25922). Thus, green synthesized RGO-supported palladium nanoparticles demonstrated that enhanced catalytic activity and antibacterial activity both play an important role in the environmental and medical disciplines.

Over the past few years, the photogenic fabrication of metal oxide nanoparticles has attracted considerable attention, owing to the simple, eco-friendly, and non-toxic procedure. Herein, we fabricated NiO nanoparticles and altered their optical properties by doping with a rare earth element (lanthanum) using Sesbania grandiflora broth for antibacterial applications. The doping of lanthanum with NiO was systematically studied. The optical properties of the prepared nanomaterials were investigated through UV-Vis diffuse reflectance spectra (UV-DRS) analysis, and their structures were studied using X-ray diffraction analysis. The morphological features of the prepared nanomaterials were examined by scanning electron microscopy and transmission electron microscopy, their elemental structure was analyzed by energy-dispersive X-ray spectral analysis, and their oxidation states were analyzed by X-ray photoelectron spectroscopy. Furthermore, the antibacterial action of NiO and La-doped NiO nanoparticles was studied by the zone of inhibition method for Gram-negative and Gram-positive bacterial strains such as Escherichia coli and Bacillus sublitis. It was evident from the obtained results that the optimized compound NiOLa-04 performed better than the other prepared compounds. To the best of our knowledge, this is the first report on the phytosynthetic fabrication of rare-earth ion Lanthanum (La3+)-doped Nickel Oxide (NiO) nanoparticles and their anti-microbial studies.

With the rapid rate of industrialization, the emission of effluents represents a serious threat to aquatic living organisms and the environment. Semiconductor-mediated photocatalysis has been highlighted as the most attractive technology for the elimination of pollutants. In this connection, bandgap-tuned ultra-small SnO2-nanoparticle-decorated 2D-Bi2WO6 nanoplates were prepared via the hydrothermal method. The tuning of the bandgap was altered by the thermal annealing procedure. Moreover, we investigated the influence of different bandgaps of SnO2 on the anchoring of the 2D-Bi2WO6 nanoplates and studied their photocatalytic activity through the degradation of Rhodamine B under visible light irradiation. The ultra-small SnO2 nanoparticles were highly anchored on the surface of the 2D-Bi2WO6 plates, which resulted in more photon harvesting, improved charge separation, the transfer of photoinduced charge carriers, and the alteration of band positions towards the visible region of light. Furthermore, the anchored SnO2 nanoparticles improved the performance of the photocatalytic activity of 2D-Bi2WO6 nanoplates by more than 2.7 times.

TiO2 nanoparticles anchored on the reduced graphene oxide (rGO) nanocomposites were prepared by hydrothermal method and characterized by the X- ray diffraction (XRD) and transmission electron microscopy (TEM). An effective electrochemical sensing platform for the detection of Rifampicin based upon TiO2 nanoparticles anchored graphene oxide sheets modified glassy carbon electrode (TiO2/rGO/GCE) is reported. Moreover, the TiO2/rGO modified glassy carbon electrode showed an excellent selectivity towards the detection of an anti-tuberculosis drug (Rifampicin). The TiO2/rGO/GCE electrochemical sensing platform is found to exhibit linear range from 0.01 – 0.1 nM with a low limit of detection 0.03 μM. The fabricated TiO2/rGO/GCE sensor is explored high sensitivity, high stable and good reproducible towards the sensing of RIF and has the potential to be utilized as a clinical assay and pharmaceuticals.

Metallic copper is a dependable co-catalyst for improving photoactivity of TiO2 photocatalysis. Cu@TiO2 core shell nanowires (NWs) were prepared by wet chemical synthesis and characterized. The microscopy images clearly show core shell morphology in nano regime. X-ray diffraction studies reveal the metallic copper and anatase TiO2 crystallinity. The optical absorption spectra exhibit ultraviolet and visible light harvesting properties. X-ray photoelectron spectroscopy confirms the presence of oxidation states of metallic copper and titanium. The photocatalytic efficiency was investigated by degrading the methyl orange (MO) and 3 wt% Cu@TiO2 core shell NWs shows highest degradation rate (k=0.02905 min−1) with superior photocatalytic activity. This material could be surely meet the necessities to harvest solar energy for many energy-related applications.

Copper nanowire (Cu NW)-based flexible transparent electronics represent an enormous breakthrough for the development of efficient, scalable and facile processing techniques. From the standpoint of commercialization, a cost-effective and eco-friendly procedure for welding nanowires is imperative to fabricate Cu NW network-based transparent electrodes. In this study, a photonic welding method using a white flash light (WFL) technique was developed in-house for welding Cu NWs in order to produce highly conductive and transparent electrodes under ambient conditions. Flexible Cu NW films with sheet resistances of 128 Ω □−1 and transmittances of >95% at 560 nm on PET substrates were obtained by using light intensity of 1.0 J cm−2 with single pulse and an irradiation time of 5 ms. The WFL technique facilitates localized surface heating and subsequent welding at the junction of the Cu NWs with excellent stability, low sheet resistance and no damage to the polymer substrates. It is expected that the WFL technique will be widely applied to flexible printed and optoelectronic devices such as touch panel displays and solar cells.

In recent years, the harvesting and management of energy has become a topic of intense interest because of the growing energy demands of society, the depletion of fossil fuel sources, and the research on eco-friendly development of efficient energy management technologies. In this connection, we proposed to utilize the energy-saving properties of electrochromic technology-based MoS2/silver nanowire (AgNW) electrodes for flexible smart windows. MoS2 is used to overcome the difficulties of stability, corrosion, and oxidation of AgNWs in the electrolyte. Transition metal chalcogenide (2D-MoS2) structures provide a unique platform to stabilize the surface of the AgNWs at the electrolyte interface. The prepared WO3/MoS2/AgNW based electrochromic device attained an optical contract of 52% at the low voltage of −1.2 V, which yielded a coloration efficiency (η) of 31.92 cm2/C. The MoS2/AgNW electrode exhibited high coloration and bleaching response, Tc = 11.5 s and Tb = 4.5 s, respectively, which is a faster response than that of the AgNW based electrochromic devices. Most of the existing electrochromic devices have advantages for next-generation smart windows and flexible and wearable optoelectronic applications.

A novel ultrasonically driven bio-reduction method was adopted to reduce the palladium chloride into palladium nanoparticles (PdNPs@CA) using coleus amboinicus extract as a green synthetic protocol. XRD confirms the formation of phase pure cubic Pd nanoparticles with the crystallite size range of 40−50 nm. The UV–vis spectrum reveals the formation of Pd nanoparticles by the disappeared peak at 480 nm of PdCl2 solution. The size distribution and surface morphology of prepared Pd nanoparticles showed spherical shaped nanoparticles with less agglomeration. The catalytic reduction behaviour of the Pd suspension is studied by 4-nitro phenol reduction process in 8 min further confirms its high catalytic performance. Synthesized PdNPs@CA were explored in ultrasound promoted Suzuki-Miyaura coupling reaction to determine the catalytic behaviour with ultrasonic frequency of 40 kHz and power of 150 W (Power sonic 410 bath sonicator) and its recycling ability is determined. It was found that aryl halides reacted with aryl boronic acids to obtain biaryl compound with excellent reaction yields in the presence of PdNPs@CA only in 30 min using PEG-400 as a green solvent. PdNPs@CA can be recovered efficiently and reused for 7 cycles without loss of its catalytic property.

Exploitation of green chemical procedures for the synthesis of metal nanoparticles by biological process has received great attention in the field of nanotechnology. To demonstrate a biogenic method that involves the reduction of aqueous gold ions by the extract of Piper longum leaves leading to the formation of different morphological gold nanoparticles (AuNPs). The formation of gold nano-structures has been characterized by UV-Vis absorption spectroscopy. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns indicates the AuNPs are highly crystalline nature with the face-centered cubic (111), (200), (220) and (311) facets, respectively. The AuNPs have different sizes and morphologies that are identified by TEM studies. The involvement of water soluble bio-molecules such as carboxylic acids, flavonoids, proteins and terpenoids were identified by Fourier transform infrared (FT-IR) and Raman spectrum. The responsible mechanism of improving acidic nature and the process of encapsulation of gold nanoparticles by Piper longum extract was discussed. Additionally, we have demonstrated the modified carbon paste electrode using gold nanoparticles by means of cyclic voltammetry in a solution of 1 M KCI and 1 mM [Fe(CN)6]3-/4-. The analysis of cyclic voltammetry shows electronic transmission rate between modified Au-CPE and Bare-CPE electrode increased.

A white light emitting phosphor NaSrB 5 O 9 :Dy 3+ was synthesized by a conventional solid state reaction method. The structure of the phosphors was analyzed by powder X-ray diffraction (XRD), revealing that the phosphors crystallized in monoclinic crystal structure with the space group ( P 2 1 /c ). Williamson–Hall (W–H) analysis was used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of NaSrB 5 O 9 :Dy 3+ phosphors. Monoclinic microstructures of nearly plate-like morphologies were observed in the FE-SEM images. Upon near-UV excitation wavelength (390 nm), the blue emission at ∼482 nm ( 6 H 15/2 ) and yellow emission at ∼584 nm ( 6 H 13/2 ) were observed in the phosphors. The critical quenching concentration of Dy 3+ in NaSrB 5 O 9 phosphor was found to be 3 at.% with the critical distance ( R c ) of ∼22.30 A and the corresponding concentration quenching mechanism was testified to be the exchange interaction between the dopant Dy 3+ ions. In order to investigate the application in white LEDs, the Commission International de l’Eclairage (CIE) chromaticity coordinates, color temperature and decay curve measurements of Dy 3+ ions doped NaSrB 5 O 9 phosphors were carried out. The yellow to blue (Y/B) emission integrated intensity ratio is maximum (∼0.9) for all the concentrations, suggesting that the phosphors favor for white illumination.

The Pepper leaves extract acts as a reducing and capping agent in the formation of silver nanoparticles. A UV–Vis spectrum of the aqueous medium containing silver nanoparticles demonstrated a peak at 458 nm corresponding to the plasmon absorbance of rapidly synthesized silver nanoparticles that was characterized by UV–Vis spectrophotometer. The morphology and size of the benign silver nanoparticles were carried out by the transmission electron microscope (TEM) and field emission scanning electron microscope (FE-SEM). The sizes of the synthesized silver nanoparticles were found to be in the range of 5–60 nm. The structural characteristics of biomolecules hosted silver nanoparticles were studied by X-ray diffraction. The chemical composition of elements present in the solution was determined by energy dispersive spectrum. The FTIR analysis of the nanoparticles indicated the presence of proteins, which may be acting as capping agents around the nanoparticles. This study reports that synthesis is useful to avoid toxic chemicals with adverse effects in medical applications rather than physical and chemical methods.

Rare-earth (Tb3+) ions doped zinc lithium bismuth borate (ZLiBiB) glasses have been prepared by melt quenching method. From the FTIR spectrum, the functional groups have been identified. From the measurements of X-ray diffraction (XRD), differential scanning calorimeter (DSC) profiles of these glasses have been carried out. In case of Tb3+:ZLiBiB glasses emission transitions such as 5D4→ 7F6 (489 nm), 5D4→ 7F5 (545 nm), 5D4→ 7F4 (584 nm) and 5D4→ 7F3 (622 nm) have been identified. Among these, the transition at 542 nm has shown a bright green emission. The emission mechanism of Tb3+ doped ZLiBiB glasses has been explained in terms of energy level diagram.

A red-emitting phosphor NaSrB 5 O 9 :Eu 3+ was synthesized by employing a solid-state reaction (SSR) method. The structures of the phosphors were analyzed by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and Raman studies. The band at ~282 nm in the excitation spectra indicated the charge transfer band (CTB) of B-O in the host, whereas the CTB of Eu-O was observed at ~275 nm for the NaSrB 5 O 9 :Eu 3+ (Eu 3+ =1 at.%) phosphor, which was supported by diffuse reflectance spectroscopy (DRS) measurements. The photoluminescence (PL) measurements exhibited a strong red emission band centered at about 616 nm ( 5 D 0 → 7 F 2 ) under an excitation wavelength of 394 nm ( 7 F 0 → 5 L 6 ). Upon host excitation at 282 nm, the pristine NaSrB 5 O 9 exhibited a broad UV emission centered at ~362 nm. The energy transfer from host to Eu 3+ ions was confirmed from luminescence spectra, excited with a 355 nm Nd:YAG laser. In addition, the asymmetric ratios indicate a higher local symmetry around the Eu 3+ ion in the host. The calculated CIE (Commission International de l′Eclairage) coordinates displayed excellent color purity efficiencies (around 99.7%) compared to other luminescent materials.

Single crystals of an organic nonlinear optical material γ-glycine have been synthesized by slow evaporation technique from aqueous solutions of α-glycine and potassium bromide at room temperature. Single crystal X-ray diffraction analysis confirmed the growth of γ phase of glycine. The powder X-ray diffraction of the grown crystal was recorded and indexed. Functional groups present in the sample were identified by FTIR spectral analysis. The optical absorption studies show that the UV cut-off wavelength of γ-glycine is at 238 nm and has a wide transparency window. The thermal characteristics of the grown crystal were determined by thermogravimetric and differential thermal analysis (TG/DTA), which show the thermal stability of the grown crystals. The powder second harmonic generation (SHG) efficiency of γ-glycine crystals was measured by Kurtz and Perry powder technique using Nd:YAG laser and it was found to be 2.56 times that of potassium dihydrogen phosphate (KDP) crystals.

Aim The aim of the present study is to synthesize the metal nanoparticles by the green chemical approaches due to their novel optical, catalytic, hydrogen storage, bio-imaging and electrochemical applications. Materials and methods 1 mM of PdCl2 and Piper betle leaf broth (10:1) are used to synthesize the stable Pd0 nanoparticles. Results The structural characterizations studied by UV-Vis Spectroscopy, XRD and FTIR-Spectroscopy. The morphology, particle distribution and size of the palladium nanoparticles were studied by TEM and SAED Techniques. The bioactivity demonstrated by synthesized PdNPs was lead to an excellent clinical use as anti-fungal material.

Nanobiotechnology is emerging as a rapid growing field with its applications in nanoscience and technology for the purpose of built-up new materials at the nanoregime. Nanoparticles produced by plant extracts are more stable, and the rate of synthesis is faster than that in the case of other organisms. In this paper we report the biosynthesis of zinc oxide nanoparticles (ZnO NPs). Structural, morphological, particle size, and optical properties of the synthesized nanoparticles have been characterized by using UV–Vis spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscope, energy-dispersive X-ray spectroscopy, atomic-force microscopy, zeta potential, X-ray diffraction, and photoluminescence intensity. The UV–Vis spectrum showed an absorption peak at 380 nm that reflects surface plasmon resonance. The optical measurements were attributed to the band gap 3.19 eV at pH 12. The zeta potential value of −36.4 eV revealed the surface charge of green synthesized ZnO NPs. The antioxidant activity was estimated by both 1,1-diphenyl-2-picrylhydrazyl and reducing power assay. Green synthesized ZnO NPs showed maximum inhibition (65.23 %) and absorbance (0.6 a.u). This approach offers environmentally beneficial alternative by eliminating hazardous chemicals and promotes pollution prevention by the production of nanoparticles in their natural environment.

This study reports on the concentration dependent fluorescence properties of Tb3+-doped lead containing calcium zinc sodium fluoroborate (LCZSFB) glasses and are analyzed by DSC, FT-IR, FT-Raman, optical absorption, emission and decay curve spectra. Co-existence of trigonal BO3 and tetrahedral BO4 units was evidenced by FT-IR and Raman spectroscopy. Judd–Ofelt theory was applied to the experimental oscillator strengths to evaluate the J–O intensity parameters. The fluorescence spectra of Tb3+-doped glasses have revealed prominent blue and green emissions originating from 5D3 and 5D4 excited levels to 7FJ ground state multiplet, respectively. The luminescent intensity of the transitions originating from 5D4 state increases with increase of Tb3+ concentration and no quenching effect is noticed up to 2 mol% of Tb3+ ions. Chromaticity color coordinates have been calculated and the dominant emission in the green region is discussed. The nature of decay curves of 5D4 level for different Tb3+ ion concentration in all LCZSFB glasses has been analyzed. Using the J–O intensity parameters as well as from the emission and decay curve measurements, various radiative and fluorescence properties have been calculated for the 5D4 fluorescent level. Based on these results, the utility of Tb3+ ions doped LCZSFB glasses as laser active materials for high intensity emissions in the green region is discussed.

Single crystals of γ-glycine, an organic nonlinear optical material have been synthesized in the presence of potassium fluoride (KF) by slow evaporation technique at ambient temperature. The size of the grown crystal is up to the dimension of 12 mm × 10 mm × 8 mm. The γ-phase was confirmed by single crystal X-ray diffraction, powder XRD and the FTIR analysis. Optical absorption spectrum reveals that the grown crystal has good optical transparency in the entire visible region with an energy band gap of 5.09 eV, which is an essential requirement for a nonlinear optical crystal. Thermal stability of the grown γ-glycine crystal was determined using the thermo gravimetric and differential thermal analyses. The NLO activity of γ-glycine was confirmed by the Kurtz powder technique using Nd:YAG laser and the grown crystal exhibits high relative conversion efficiency when compared to potassium dihydrogen phosphate (KDP).