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In this study, vermiwash derived—enzyme enriched ZnO NPs co-doped with copper and nitrogen were synthesized using soft chemical method for cost-effective and eco-friendly photocatalytic dye degradation. Undoped and copper (cationic), nitrogen (anionic) and copper + nitrogen (cationic + anionic) doped ZnO NPs were synthesized separately and compared with their vermiwash derived—enzyme enriched counterparts. Vermiwash—an aqueous liquid obtained from vermi reactor of Eudrilus eugineae earthworm—was used as a reducing agent along with NaOH for the synthesis process. The presence of four enzymes viz. phosphatase, urease, protease and amylase was confirmed through enzymes activity studies. The enzymes quantitative study clearly showed that the enzymes prevalent in the vermiwash are inherited by the vermiwash activated nanoparticles as well as by the photocatalytically treated water. The photocatalytic dye degradation efficiency of the ZnO:Cu:N:vermi nanopowder against the methylene blue dye was found to be 99% which is the best among all the other synthesized counterparts. The photocatalytic dye degradation efficiencies of the enzyme enriched samples were in the order: ZnO:vermi < ZnO:N:vermi < ZnO:Cu:vermi < ZnO:Cu:N:vermi. The same order is observed in the bare samples also: ZnO < ZnO:N < ZnO:Cu < ZnO:Cu:N. The mechanism lying behind the enhanced photocatalytic ability of the vermiwash activated ZnO:Cu:N NPs is illustrated in the paper. The results obtained from the X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) and enzyme quantitative studies were correlated with the proposed dye degradation mechanism of the vermiwash activated ZnO:Cu:N nanomaterial. The synthesized nanomaterials have good reproducibility and stability. The results showed that the synthesized vermiwash activated ZnO:Cu:N NPs have great potential for the effective degradation of various toxic organic dyes. [ABSTRACT FROM AUTHOR]

This study focuses on the preparation of enzyme-activated zinc oxide nanomaterial using vermiwash via a simple soft chemical method. This vermiwash––an aqueous extract obtained from vermin reactor––is produced using earthworm, Eudrilus eugeniae, cow dung and leaf litter. The prepared nanoproduct was used to decompose toxic dye molecules through photocatalysis. The enzymes present in the vermiwash (like amylase, phosphatase, urease and protease) are found to be inherited by the prepared nanoproduct as well as the photocatalytically treated water. The quantitative study of enzymes shows that the quantity of enzymes present in the nanoproduct as well as in the photocatalytically treated water increases as the proportion of vermiwash used in the starting solution increases. This increase in the quantity of enzymes causes an increase in the photocatalytic efficiency of the nanoproduct. The photocatalytically treated water which consists of enzymes can be used as a potential candidate for effective irrigation. Thus, the vermiwash-activated ZnO nanopowder prepared in this study shows a two linear cascading applications. The results of the studies on enzymes, photocatalysis, XRD, SEM and FTIR are appropriately correlated with one another to address the enhancement in the photocatalytic activity of the prepared nanomaterials and the underlying mechanism. [ABSTRACT FROM AUTHOR]

Lanthanum-doped zinc oxide (ZnO:La) thin films were deposited using a nebulizer spray technique with La concentrations 0, 1, 3 and 5 wt%. The structural, morphological and gas sensing properties were studied. All the film samples exhibit considerable ammonia sensing ability. The gas sensing results show that the ZnO:La film with 3 wt% of La doping exhibits remarkable sensing response and fast response/recovery times (39 s/11 s) for 100 ppm of NH3 at room temperature. The reasons for the enhanced sensing ability of the doped films have been addressed with the help of the underlying mechanism, atomic force microscopy (AFM) and photoluminescence (PL) results. [ABSTRACT FROM AUTHOR]

Here, 1 mol% Dy,Ce co-doped ZnO nanoparticles were synthesized via a simple, cost-effective combustion method which could produce large-scale products. The structure and phase purity of synthesized nanoparticles were shown by X-ray diffraction, selected-area-electron-diffraction patterns and Raman spectroscopy to be a hexagonal wurtzite structure with no secondary peaks. Spherical morphology was shown by field emission scanning electron microscopy and high-resolution transmission electron microscopy. The presence of dopants with elemental composition was authenticated by energy dispersive spectroscopy and elemental mapping. Enhanced reflectance in the visible region for Ce-doped ZnO samples was noted by diffuse reflectance spectroscopy. An increase in the bandgap for doped samples was indicated by the Kubelka–Munk function. Significant visible luminescence was observed, which varied with different excitations. The room-temperature weak ferromagnetic behaviour of 2 mol% Ce-doped ZnO and distinct paramagnetic behaviour of 1 mol% Dy,Ce co-doped ZnO was detected using vibrating sample magnetometry. [ABSTRACT FROM AUTHOR]

Pure and Fe doped ZnO nanoparticles were prepared by a facile and cost-effective co-precipitation method. The X-ray diffractograms (XRD) reveal that the grown nanoparticles are hexagonal in structure and the crystallite sizes are in the range of 27-28 nm. The transmission electron microscope (TEM) micrographs confirmed the spherical nature of the grown particles and the Fourier transform-infrared (FT-IR) studies confirmed the presence of Zn-O bonding in the prepared nanoparticles. Additionally, the presence of the constituent elements is confirmed with XPS analysis. The optical bandgap of the prepared nanoparticles are calculated as 3.28, 3.19 and 3.08 eV for ZnO, ZnO-Fe 10 at.% and ZnO-Fe 20 at.%, respectively. The photocatalytic dye degradation efficiency against methylene blue, is 68.52, 73.96, and 87.92, respectively. To validate the photocatalytic activity, a DFT based calculation was performed to measure the band edge positions of the pure and Fe doped ZnO nanostructures, and the obtained results are well supported by the experimental results. [ABSTRACT FROM AUTHOR]

ZnO is an II-VI compound semiconductor possessing wide, direct bandgap (3.37 eV) and high excitonic binding energy (60 meV) even at room temperature. High crystalline ZnO nanostructures show distinctive characteristics in light emission, particularly in lasing applications. Here, in this work, rare earth doping in ZnO was carried out to enhance its photoluminescence property. Pure, 2 mol% Dy doped, 2 mol% Gd doped and 1 mol% Dy and Gd co-doped ZnO nanoparticles were synthesized via easy combustion technique. The synthesized nanoparticles were characterized by X-ray diffraction, Fourier Transform Infra Red Spectroscope, Field Emission Scanning Electron Microscope, High Resolution Transmission Electron Microscope, Diffuse Reflectance Spectroscope and Photoluminescence. Enhancement of Photoluminescence in 1 mol% Dy and Gd co-doped ZnO nanoparticles is observed. [ABSTRACT FROM AUTHOR]

Undoped and Bi doped zinc oxide nanoparticles were synthesized by soft chemical method. The effects of doping on structural and optical properties of Bi doped nanoparticles were investigated. The product was subjected to powder X-ray diffraction, field emission scanning electron microscope, transmission electron microscope and photoluminescence techniques. The crystallite sizes of synthesized samples were calculated from the powder XRD patterns, the crystalline size is variable from 42 to 56 nm for undoped and Bi doped ZnO nanoparticles respectively. The photoluminescence intensity of the Bi (7 at.%) doped ZnO was much higher than that of undoped ZnO nanoparticles. The undoped and Bi doped ZnO nanoparticles are subjected to antibacterial bio activity against both Staphylococcus aureus and Escherichia coli bacteria in order to find the materials efficiency towards the bacterial strains and it is found that there is a good zone of inhibition. [ABSTRACT FROM AUTHOR]

This study focuses the effect of Mg doping level (0-12 at.% in steps of 3 at.%) on the photocatalytic efficacy of ZnO:F:Mg nanopowder synthesised using a simple cost-effective chemical method. The structural, surface morphological, photoluminescence studies were carried out for all the samples. The photocatalytic dye degradation study under visible light against the two different dyes viz methylene blue (MB) and malachite green (MG) revealed that ZnO:F:Mg nanopowder doped with 12 at.% of Mg shows superior photocatalytic activity compared to other doped and undoped samples for both the dyes examined. The degradation efficiency of undoped ZnO is found to be 65 and 74% for MB and MG, respectively, whereas the F + Mg co-doped ZnO nanopowder (10 + 12 at.%) exhibits enhanced photocatalytic activity against both the dyes and the degradation efficiency values for MB and MG are 88 and 97%, respectively. The reasons for this enhancement are addressed appropriately with the evidences obtain from photoluminescence and X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

Mg and RGO activated ZnO nanocomposites were prepared using a low-cost soft chemical method. As per the structural studies the samples exhibit wurtzite structure of ZnO with hexagonal crystal system. No secondary phases were observed. The photocatalytic activity of the prepared samples were assessed through the degradation of cationic dyes, methylene blue (MB) and malachite green (MG) under visible light irradiation. The studies revealed that the ZnO:Mg/RGO nanocomposite exhibits enhanced photocatalytic as well as antibacterial behavior compared to bare ZnO. The optical, structural and surface morphological studies support the reports on the photocatalytic and antibacterial activities of the synthesized samples. [ABSTRACT FROM AUTHOR]

Fe doped ZnO nanoparticles were synthesized using simple soft chemical route by varying the Fe doping level (5, 10 and 15 at.%). The obtained samples were characterized for their structural, optical, surface morphological and antibacterial properties. XRD profiles confirmed that the synthesized material is nanocrystalline ZnO with hexagonal wurtzite structure. The XRD studies reveal that the crystalline size of Fe doped ZnO nanoparticles are range from 56 to 24 nm. The size of the particle decreases gradually as Fe content is increased. The surface morphological studies confirmed the nanosize of the obtained particles. The FESEM and TEM images show that the particle size reduces after doping. The EDAX profiles confirmed the presence of expected elements in the final product. The Photoluminescence studies showed the occurrence of energy transition from ZnO to dopant site. The antibacterial activity of Fe doped ZnO nanoparticles against Staphylococcus aureus (Gram-positive) were found to be significantly higher than that against the Bacillus subtilis (Gram-positive) micro-organism. [ABSTRACT FROM AUTHOR]

Transparent conducting oxide films of undoped, Mo doped, Mo + F co-doped ZnO were deposited using a facile homemade nebulizer spray pyrolysis technique. The effects of Mo and F doping on the structural, optical, electrical and surface morphological properties were investigated using XRD, UV-vis-NIR spectroscopy, I–V and Hall probe techniques, FESEM and AFM, and XPS, respectively. The XRD analysis confirms that all the films are well crystallized with hexagonal wurtzite structure. All the synthesized samples exhibit high transmittance (above 85%) in the visible region. The current-voltage (I–V) characteristics show the ohmic conduction nature of the films. The Hall probe measurements show that the synergistic effects of Mo and F doping cause desirable improvements in the quality factor of the ZnO films. A minimum resistivity of 5.12 × 10 −3 Ω cm with remarkably higher values of mobility and carrier concentration is achieved for Mo (2 at.%) + F (15 at.%) co-doped ZnO films. A considerable variation in the intensity of deep level emission caused by Mo and F doping is observed in the photoluminescence (PL) studies. The presence of the constituent elements in the samples is confirmed by XPS analysis. [ABSTRACT FROM AUTHOR]

Undoped ZnO, ZnO:Ag and ZnO:Ag/RGO (reduced graphene oxide) nanopowders were synthesized using co-precipitation method. The photocatalytic, antibacterial, structural, surface morphological and optical properties of the synthesized nanopowders were studied. From the X-ray diffractometer profiles, it is found that all the samples exhibit hexagonal structure without any secondary phase. The photocatalytic and antibacterial studies show that ZnO:Ag/RGO nanopowders exhibit enhanced photocatalytic and antibacterial activities when compared with undoped ZnO and ZnO:Ag nanopowders. The variations observed in the intensities of the PL emission peaks are correlated with the enhanced photocatalytic and antibacterial efficiencies. [ABSTRACT FROM PUBLISHER]

Cobalt activated ZnO nanocomposites have been successfully grown on reduced graphene oxide (rGO) nanosheets via a cost-effective and simple soft chemical method to obtain ZnO:Co/rGO nanocomposites for the simultaneous enhancement of photocatalytic and antibacterial activities. The obtained samples were characterized for their structural, optical, surface morphological, photocatalytic and antibacterial properties. XRD profiles confirmed that the synthesized material is nanocrystalline ZnO with hexagonal wurtzite structure. The photocatalytic activities of the synthesized samples were evaluated by observing the degradation of methylene blue (MB), a representative organic dye, under visible light irradiation. The photodegradation of MB was found to follow pseudo-first order kinetics. Compared with bare ZnO, the Co +rGO activated ZnO nanocomposites exhibit significantly enhanced photocatalytic and antibacterial activities due to the synergetic effects of various mechanisms related to the Co and rGO incorporation. These mechanisms are elaborated in detail with the help of appropriate schematic diagram along with the support of XRD, photoluminescence, UV–visible absorption, FTIR, FESEM , and TEM results. [ABSTRACT FROM AUTHOR]

Undoped, Fe doped and Fe+F doped ZnO films were prepared using simplified spray pyrolysis technique by employing a perfume atomizer at the substrate temperature of 350˚C. Structural, surface morphological, optical and magnetic properties of thin films have been investigated by X-ray powder diffraction (XRD), scanning electron microscope (SEM), UV-vis- NIR spectrophotometer and vibrating sample magnetometer (VSM), respectively. From the results, it is observed that all the films possess hexagonal wurtzite structure of zinc oxide having crystallite sizes in the range of 47-50nm. The SEM image of the prepared sample show that the grain size tends to decrease with double (Fe+F) doping. Fe and F incorporation hardly influences the transmittance in the visible range. Magnetic measurement revealed the presence of room temperature ferromagnetism in all the three films.With Fe doping the magnetization increases and the coercivity decreases whereas with Fe+F doping, ZnO film shows the magnetization increases and the coercivity becomes half of its value. [ABSTRACT FROM AUTHOR]

The present study reports the antibacterial activities of undoped and Ag (2 at.%) + Co (5 at.%) doped ZnO nanopowders synthesized using combustion method. The synthesized particles have been tested to find the effect of doping on the antibacterial activities against two different pathogens namely Shigella flexneri and Bacillus Cereus. Further structural, morphological, chemical, compositional and optical properties were studied using X ray diffractometer (XRD), Field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), UV-vis spectroscopy and Photoluminescence spectroscopy, respectively. The results reveal that Ag + Co doped ZnO shows better antibacterial activity against both the tested bacterial strains when compared with bare ZnO. The possible mechanism for the antibacterial activity of Ag + Co doped ZnO is reported [ABSTRACT FROM AUTHOR]

The focus of this work is to realize ZnO microparticles with simultaneously enhanced antibacterial and magnetic properties through a double cationic (Mg+Co) doping. Undoped and magnesium (Mg)+ cobalt (Co) doped ZnO microparticles were synthesized using a cost-effective simple soft chemical route. Their surface morphological, magnetic, antibacterial and structural properties were investigated. Antibacterial studies of the prepared samples were carried out against a Gram Positive and Gram Negative bacteria. From the antibacterial studies, it is found that the double cationic doped ZnO microparticles exhibit superior antibacterial efficiency compared with undoped and single cationic doped ZnO microparticles. The FESEM images show that the undoped and single cationic (Mg/Co) doped ZnO particles have hexagonal block structures of micro scale dimensions whereas the double cationic doping causes the formation of hexagonal plate structures having near nanoscale thickness (~150 nm), thereby increasing the effective reactive surface area. The magnetization curves show that the coexistence of Mg 2+ and Co 2+ ions in the ZnO lattice causes a pronounced increase in the ferromagnetic behavior, already present in the undoped and single cationic doped ZnO material. The XRD, FTIR and PL results support the discussion on the antibacterial and magnetic results. The EDAX profiles and the compositional mapping images confirm the presence of expected proportions of the constituent elements and their uniform distribution in the final product. Structural studies show that the products exhibit hexagonal wurtzite structure of ZnO without any secondary phases. [ABSTRACT FROM AUTHOR]

In the present study, Ag+Mn and Ag+Mn+F doped ZnO nanopowders were synthesized using a combustion method and their magnetic, structural, surface morphological and antibacterial properties were studied. The magnetic studies reveal that the doped ZnO nanopowders exhibit superparamagnetic behavior. Surface morphological studies show that the grain size of the undoped ZnO is about 250 nm and the size reduces by one order of magnitude (from 250 nm to 23 nm) after doping. The reason for this drastic decrease in the grain size and crystallite size is explained on the basis of Zener Pinning Effect. The antibacterial efficiency of the synthesized nanopowders is tested against two different bacteria viz. Escherichia Coli and Klebsiella Oxytoca and it is found that the antibacterial efficiency of ZnO nanopowder increases remarkably after multiple doping. All the doped and undoped nanopowders exhibit better efficiency against K. oxytoca than E. coli . The PL results confirm the presence of certain intrinsic and extrinsic defects in the crystalline structure. [ABSTRACT FROM AUTHOR]

Undoped, Co doped and Co + F doped ZnO nanopowders were synthesized using a simple soft chemical method and certain physical and antibacterial properties of the samples were studied and reported. The XRD patterns reveal that the samples has hexagonal wurtzite structure with preferential orientation along (101) plane. Reduction in grain size caused by Co and Co + F doping is observed from FESEM images. The observed photoluminescence peaks related to the defects confirmed the incorporation of Co, Co + F into the ZnO lattice. Co + F doped ZnO nanopowder exhibits higher antibacterial activity than undoped and Co doped ZnO nanopowders against all the four different bacteria tested in this study viz. B. subtilis, S. aureus, E. coli and P. aeruginosa. The enhanced antibacterial activity of doubly doped ZnO nanopowder is mainly due to the generation of hydroxyl radicals (OH) in the system. [ABSTRACT FROM AUTHOR]

Tantalum doped ZnO thin films (doping levels – 0, 1, 3 and 5 at %) were deposited onto glass substrates using a simplified spray pyrolysis technique by employing a perfume atomizer for the first time. The effects of Ta doping level on electrical, optical and structural properties along with surface morphology of ZnO films were studied. EDAX and FTIR studies confirm the presence of the dopant in the prepared film. The chemical states of the constituent elements were analysed through XPS studies. The average optical transmittance of the film is over 90%. Even though the intensity of (001) peak increases at the expense of (002) plane with Ta doping, the direction of preferential growth is unaltered. The FESEM analysis shows that the dopant alters the grain size of the films. A minimum electrical resistivity of 2.05 × 10 −3 Ω cm was obtained at the doping level of 1 at%. The obtained good quality factor (1.584 × 10 −4 (Ω/sq.) −1 ) of the film at 1 at% of Ta doping level makes it a potential candidate for several opto-electronic devices like transparent electrodes, thin film transistors and many other functional devices. [ABSTRACT FROM AUTHOR]

Zr- and (Zr + F)-doped ZnO nanopowders were synthesized using a simple soft chemical route having Zr and F doping concentrations as 3 and 10 at.%, respectively. The structural, morphological, optical, magnetic and antibacterial properties of these samples are studied and compared with those of undoped ZnO. The X-ray diffractometer studies reveal that the synthesized nanopowders exhibit hexagonal wurtzite structure of ZnO, and the crystallite size increases after doping. The field effect scanning electron microscope and transition electron microscopy images show that the synthesized ZnO nanopowders have reduced grain size after doping. The dopant-induced room temperature ferromagnetism is observed from vibrating sample magnetometer studies. Enhancement in the antibacterial efficiency due to doping against three different bacterial strains,viz. Bacillus subtillis,Staphylococus aureusandPseudomonas aeruginosaare studied and reported. [ABSTRACT FROM AUTHOR]

Undoped and fluorine doped ZnO thin films were deposited onto glass substrates using successive ionic layer adsorption and reaction (SILAR) technique and then annealed at 350 °C in vacuum ambience. The F doping level was varied from 0 to 15 at% in steps of 5 at%. The XRD analysis showed that all the films are polycrystalline with hexagonal wurtzite structure and preferentially oriented along the (002) plane. Crystallite sizes were found to increase when 5 at% of F is doped and then decreased with further doping. It was seen from the SEM images that the doping causes remarkable changes in the surface morphology and the annealing treatment results in well-defined grains with an improvement in the grain size irrespective of doping level. All the films exhibit good transparency (>70%) after vacuum annealing. Electrical resistivity of the film was found to be minimum (1.32×10 −3 Ω cm) when the fluorine doping level was 5 at%. [ABSTRACT FROM AUTHOR]

Fluorine doped zinc oxide (FZO) and fluorine doped tin oxide (FTO) films were deposited onto glass substrates at a temperature of 350 °C using spray pyrolysis technique. The annealing induced changes in the structural, optical, electrical and surface morphological properties were studied. The structural studies reveal that the post deposition annealing treatment causes drastic changes in the orientation of the crystallites in the case of FZO films whereas it does not affect significantly the structural properties of FTO films. These annealing induced changes in the structural properties of FZO film are reflected appropriately in optical, electrical and surface morphological properties also. But, no noticeable changes were observed in the case of FTO films. [ABSTRACT FROM AUTHOR]

Undoped and doubly (Mn+Co) doped ZnO nanopowders were synthesized with different doping levels of Co (1, 2, 3, 4 and 5 at%) and constant Mn doping level (10 at%) using a simple soft chemical route. XRD profiles confirmed that the synthesized material is nanocrystalline ZnO with hexagonal wurtzite structure. No peaks other than the characteristic ZnO peaks were observed in the XRD pattern confirming the absence of any secondary phase. Antibacterial activities of synthesized ZnO nanopowders were tested against Staphylococcus aureus bacteria using agar well diffusion method. It was found that the antibacterial efficiency of the doubly doped ZnO nanopowders was remarkably high when the Co doping level was 5 at%. The obtained PL, SEM and TEM results are corroborated well with the antibacterial activity. Magnetic measurements showed that undoped ZnO sample exhibits diamagnetic behavior and as the Co doping level increases, the nanopowder behaves as a ferromagnetic material. [ABSTRACT FROM AUTHOR]

Sn and Mn co-doped ZnO thin films were deposited onto glass substrates using sol-gel spin coating technique by keeping the Sn doping concentration in the starting solution at 6 at.% and by varying the Mn concentration from 0 to 10 at.% in steps of 2 at.%. The influence of Mn doping on the structural, electrical, optical, photoluminescence, magnetic and surface morphological properties were studied. The antibacterial activity was studied against Staphylococcus aureus bacteria. The structural studies revealed that all the films are grown along the (002) plane, irrespective of the doping concentration. The crystallite size decreases as the doping level is increased. The resistivity is minimum (5.49 × 10 Ω cm) at 8 at.% of Mn. All the films exhibit good transparency (85 %) in the visible region. The optical band gap of the films is found to be in the range of 3.27-3.41 eV. [ABSTRACT FROM AUTHOR]

Ag and (Ag + F) doped ZnO nanopowders were synthesized using combustion method by varying the F doping level (5, 10, 15 and 20 at.%) and keeping a constant Ag doping level (2 at.%). The obtained samples were characterized for their structural, optical, surface morphological and antibacterial properties. XRD results showed that all the samples exhibited preferential orientation along the (101) plane. The variation in the crystallite size with the increase in F doping level is explained on the basis of the Zener pinning effect. FTIR and photoluminescence studies confirmed the incorporation of Ag and F into the ZnO lattice. The carrier concentration was found to increase with the increase in F doping level up to 10 at.% as evidenced by the blue shift in the NBE peak. From the studies, it was found that 10 at.% of F doping is optimal to achieve better antibacterial efficiency against three different bacteria viz . Staphylococcus aureus , Escherichia coli and Salmonella typhi . The influence of the shape and size of the ZnO:Ag:F nano grains on the antibacterial activity is analyzed using the SEM and TEM images. [ABSTRACT FROM AUTHOR]

Undoped and Fe+F doped ZnO powders were prepared using a simple and low cost soft chemical method. The Fe doping level was varied from 0 to 10 at% in steps of 2 at% and the F doping level was kept constant at 10 at%. The XRD studies showed that the prepared powders have hexagonal wurtzite structure of ZnO. The variation in the periodicity of the crystalline ZnO powders as evidenced from the variation in the intensities of the XRD lines is correlated with Fe and F incorporation in the ZnO lattice. The PL and FTIR results supported these incorporations. The SEM images revealed that the grains have perfect hexagonal shape with the side greater than 200 nm up to the Fe doping level of 4 at% and then it decreased drastically to nano level when the doping level is greater than 6 at%. From the antibacterial studies, it is found that the grain size plays a key role in determining the antibacterial efficiency of the prepared ZnO powder. [ABSTRACT FROM AUTHOR]

Abstract: In this investigation transparent conducting properties of as-deposited and annealed ZnO:Sn:F films deposited using different spray flux density by changing the solvent volume (10 mL, 20 mL … …50 mL) of the starting solutions have been studied and reported. The structural analyses of the films indicate that all the films have hexagonal wurtzite structure of ZnO with preferential orientation along (002) plane irrespective of the solvent volume and annealing treatment whereas, the overall crystalline quality of the films is found to be enhanced with the increase in solvent volume as well as with annealing. This observed enhancement is strongly supported by the optical and surface morphological results. From the measurements of electrical parameters, it is seen that, the annealed films exhibit better electrical properties compared to the as-deposited ones. Annealing has caused agglomeration of grains as confirmed by the surface morphological studies. Also, the annealing process has led to an improvement in the optical transparency as well as band gap. It is found from the analyses of the characteristics of the as- deposited and annealed films that the annealed film deposited from starting solution having solvent volume of 50 mL is optimal in all respects, as it possesses all the desirable characteristics including the quality factor (1.60 × 10−4 (Ω/sq.)−1). [Copyright &y& Elsevier]

ZnO nanopowders simultaneously doped with fluorine (20 at.%) and magnesium (4, 8, 12 and 16 at.%) (ZnO:F:Mg) have been synthesized using an inexpensive simple soft chemical route for the first time. The effect of Mg doping level on certain physical properties and antibacterial activities of ZnO:F:Mg nanopowders has been investigated and reported. XRD studies showed that the products have the hexagonal wurtzite structure of ZnO. Fourier transform infrared spectra authenticate the presence of MgO stretching vibration, which is responsible for the increased antibacterial activity of the synthesized samples. The antibacterial activity of ZnO:F:Mg nanopowders was found to be enhanced with increase in Mg doping level as it causes a reduction in the grain size. [ABSTRACT FROM AUTHOR]

Abstract: Manganese (Mn) doped ZnO nanopowders (0, 2, 4, 6, 8 and 10at%) were synthesized using a simple soft chemical route and their structural, optical, surface morphological, magnetic and antibacterial properties were investigated. Structural studies show that the nanopowders exhibit hexagonal wurtzite structure of ZnO. No other secondary phases like MnO2, MnO, Mn3O4 and Mn2O3 are observed. The blue shift observed in the photoluminescence spectra beyond the Mn doping level of 6at% shows that there is an increase in the carrier concentration, caused by the interstitial incorporation of Zn and Mn in the ZnO matrix. From the antibacterial studies, it is found that ZnO:Mn nanopowders with higher Mn doping level (8 and 10at%) exhibit good antibacterial efficiency against Escherichia coli (E. coli) bacteria. The magnetization curves obtained using vibrating sample magnetometer (VSM) show a sign of strong room temperature ferromagnetic behavior when the Mn doping level is 6at% and a weak room temperature ferromagnetic behavior, when the Mn doping level is below 6at%. Beyond 6at% they are found to exhibit antiferromagnetic and paramagnetic properties, when the Mn doping levels are 8 and 10at%, respectively. The SEM images indicate that there is a gradual decrease in the grain size with increase in the Mn doping level. The EDAX profile clearly confirms the presence of expected elements in the final product, in appropriate proportions. [Copyright &y& Elsevier]

Highlights: [•] First report on the antibacterial properties of F doped ZnO nanopowder. [•] Physical properties corroborated well with the antibacterial results. [•] Tuning of surface morphology to enhance the antibacterial efficiency-F doping. [Copyright &y& Elsevier]

Highlights: [•] The deposited novel double layer film is found to have good thermal stability. [•] Double layered system possesses lesser R sh than that of single layered films. [•] Structural, optical and electrical results are well corroborated. [Copyright &y& Elsevier]

Highlights: [•] Study on the role of protective tin oxide over layer on zinc oxide thin films. [•] Excellent corroboration of different results. [•] Confirmation of thermal stability by means of annealing treatment. [Copyright &y& Elsevier]

Single layered aluminium doped tin oxide (ATO), fluorine doped zinc oxide (FZO) and bi-layered ATO/FZO thin films were deposited onto preheated glass substrates (T = 340 ± 5 °C) using a low-cost and simplified spray pyrolysis technique. The structural, optical, electrical and surface morphological properties of the bi-layered ATO/FZO thin films were studied and compared with that of the single layered films. The average optical transmittance of the bi-layer film in the visible range was found to be around 80 %. The bi-layered ATO/FZO films possessed both better transmittance in the visible range and sharp absorption edge, the unique desirable features of ATO and FZO films, respectively. The optical band gap (E) value of the bi-layer coating (3.22 eV) was found to lie between the E values of single layered ATO (3.71 eV) and FZO (3.20 eV) films. Sheet resistance values of ATO and FZO single layer films were 3.47 and 11.2 kΩ/sq., respectively. The bi-layered ATO/FZO thin films exhibited a sheet resistance of 4.42 kΩ/sq. which was very much close to that of ATO films and three times less than that of FZO film. The AFM images showed the good packing density and homogeneity of the surface of the bi-layer films. The annealing studies clearly showed that the ATO over layer remarkably improved the thermal stability of the bi-layered film. [ABSTRACT FROM AUTHOR]

Abstract: The effect of simultaneous doping of cadmium and fluorine on certain physical properties of ZnO nanopowders synthesized using a simple soft chemical route is reported for the first time. The structural studies indicated that doping do not alter the overall structure. However, the values of lattice constants are found to increase with the increase in the dopant levels. The optical studies showed a decrease in band gap for doped system associated with Moss–Burstein effect. The composition and morphology are reported and correlated with FTIR and photoluminescence studies. The morphology is explained on the basis of zeta potential measurements. [Copyright &y& Elsevier]

Abstract: ZnO nanopowders simultaneously doped with Sn and F are synthesized by employing a simple soft chemical route. The effect of simultaneous doping on the structural, optical and surface morphological properties are investigated in detail and reported. The structural, FTIR and Raman studies revealed the proper Sn and F incorporation into the ZnO matrix. The synthesized nanoparticles exhibit the Raman bands at 335, 386, 423, 440 and 553cm−1 which were assigned to wurtzite-type ZnO. The blue shift in the absorption spectrum, caused by the doping process suggests an increase in the optical band gap. The PL studies showed the occurrence of energy transition from ZnO to dopant sites. The surface morphological studies confirmed the nanosize of the obtained powder particles. The EDAX profiles confirmed the presence of expected elements in the final product. The characteristics of the synthesized nanopowders showed that they are potentially significant for several technological applications. [Copyright &y& Elsevier]

Fluorine-doped zinc oxide (FZO) films were deposited from aged starting solutions having different solvent volumes (10, 20, 30, 40 and 50 ml) using a simplified spray pyrolysis technique. The electrical studies showed that the resistivity is minimum (4.68 × 10-2 Ω cm) for lowest solvent volume (10 ml) and the value progressively increased with the increase in the solvent volume indicating that the fluorine incorporation increases with solvent volume. The systematic study clearly showed that the spray flux rate plays a crucial role in determining the electrical, optical, surface and structural properties of the FZO films. The optical transparency is found to be gradually increased (from 85 to 95%) as the volume of the solvent increases. The scanning electron microscope images depicted that the decrease in the spray flux rate caused an enhancement in the grain size. The X-ray diffraction profile clearly showed that all the films have preferential orientation along the (002) plane with hexagonal wurtzite structure. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Herein, undoped and Ga doped ZnO nanoparticles were prepared using a combustion method. The effect of Ga doping on the structural, optical, surface morphological and antibacterial properties was explored. The hexagonal wurtzite structure and the preferential (101) plane orientation were confirmed by powder X-ray diffraction (PXRD) studies. The Raman active modes of ZnO phase were found using Raman spectral analysis. The occurrence of the functional groups and chemical bonding was affirmed by FTIR spectra. HRSEM images revealed that the spherical shaped particles are agglomerated and contained several voids. The antibacterial efficacy of the prepared nanoparticles was examined against different bacteria viz. Escherichia coli , Klebsiella pneumoniae and Staphylococcus aureus. From this analysis, it is found that the undoped and Ga doped ZnO nanopowders remarkably enhances the antibacterial activity. [ABSTRACT FROM AUTHOR]

Zr and Zr+Fe co-doped ZnO nanopowders were synthesized using a simple soft chemical method keeping the doping level of Zr as constant (3 at%) and varying the doping level of Fe (1,5and 10 at%) in the precursor solution. The XRD studies reveal that the synthesized nanopowders exhibit hexagonal wurtzite structure of ZnO. The crystallite size of ZnO:Zr nanopowders is found to be 63 nm and then the size decreases gradually with the increase in the Fe doping level and attains a minimum of 28 nm at 10 at% of Fe doping level. The Zr doped ZnO nanopowders are found to have ferromagnetic property. The material exhibits paramagnetic nature up to 5 at% of Fe doping level. At 10 at% of Fe doping level superparamagnetic behavior is observed. The antibacterial efficiency against two different bacterial strains viz Bacillus subtilis and Escherichia coli is studied. The antibacterial efficiency is found to be the maximum at 10 at% of Fe doping level. [ABSTRACT FROM AUTHOR]

The present study aims to develop zinc-zinc oxide-zinc phosphate (hopeite)-magnesium ammonium phosphate (struvite) composite coatings to reduce the rate of degradation and to impart a better bioactivity for Mg. Galvanic deposition was employed to form Zn-ZnO coating on Mg, which was subsequently converted to hopeite and struvite by chemical conversion method using diammonium hydrogen phosphate. The structural and morphological characteristics, nature of functional groups, degradation behaviour in Hanks' balanced salt solution (HBSS) and bioactivity in simulated body fluid (SBF) were evaluated. The findings of the study revealed that Zn-ZnO-hopeite-struvite composite coating has considerably reduced the rate of degradation of Mg in HBSS and promoted the bioactivity of Mg in SBF. The rate of degradation of Mg is decreased from 1.27 ± 0.11 mm/y to 0.13 ± 0.04 mm/y, amounting to ⁓90 % reduction in the corrosion rate. The morphological features reveal that the extent of corrosion attack on Zn-ZnO-hopeite-struvite composite coated Mg is very much limited when compared to that of the uncoated one. The surface of Zn-ZnO-hopeite-struvite composite coated Mg shows many thin needle-like crystals as well as globular-like particles after immersion in SBF when compared to that of uncoated and Zn-ZnO coated Mg. The uniform and compact coating with good adherence, improved corrosion resistance and better bioactivity suggest that Zn-ZnO-hopeite-struvite composite coating is a promising surface modification approach towards the development of Mg-based degradable implants. [Display omitted] • Zn-ZnO coating is formed on Mg by galvanic deposition. • Zn-ZnO is converted to hopeite – struvite composite by chemical conversion method. • Zn-ZnO-hopeite-struvite composite coating improved corrosion resistance of Mg in HBSS. • Zn-ZnO-hopeite-struvite composite coated Mg moderately promoted the bioactivity. [ABSTRACT FROM AUTHOR]

Molybdenum doped zinc oxide (ZnO:Mo) nanoparticles and ZnO:Mo/g-C 3 N 4 nanocomposites were prepared via green synthesis by using Morinda citrifolia (M. citrifolia) extract as the reducing agent. Another set of ZnO:Mo and ZnO:Mo/g-C 3 N 4 nanomaterials were prepared using NaOH as the reducing agent and their photocatalytic efficiencies against methylene blue (MB) and methyl orange (MO) were evaluated and compared with those of their green synthesized counterparts. The degrading efficiency of green synthesized ZnO:Mo/g-C 3 N 4 was 99 and 96 % against MB and MO of dyes, respectively, whereas the respective values in the case of chemical synthesis are only 95 and 90 %. The mechanism lies behind the photocatalytic activity of the nanocomposite was elaborated. The enhanced charge carrier concentration caused by Mo doping and the synergistic advantages of the composite partners, like band gap reduction and reduced recombination rate are discussed with relevant references. The water samples photocatalytically treated by the nanomaterials were applied to green gram seeds and the growth process is evaluated and compared. The powder XRD, field emission SEM, TEM, FTIR and EDAX results and the related analyses are presented as corroborative evidences for the composite formation and enhanced photocatalytic activity. The prepared green synthesized ZnO:Mo/g-C 3 N 4 nanocomposite will be a promising material for de-toxification of dye effluents to make it conducive for seed germination and plant growth. [Display omitted] • Cost effective and eco-friendly preparation of ZnO:Mo/g-C 3 N 4 using Morinda citrifolia leaf extract for the time. • Complete detoxification of dye solution through photocatalysis. • Assessment of detoxification by a simple and novel seed germination process. [ABSTRACT FROM AUTHOR]

Abstract: Simultaneous doping of aluminum (Al) and fluorine (F) on ZnO nanopowder was successfully achieved by a soft chemical method. The strong X-ray diffraction peaks revealed the high crystallinity of the synthesized nanopowder and the XRD profiles showed that the material has hexagonal wurtzite structure. EDAX results confirmed the presence of Al and F and from the quantitative analysis it was observed that there was a systematic increase in both dopants in the final product as they were included in the starting solution. The SEM images showed that the ZnO:Al:F powders have nanorod structure with hexagonal cross section. The simultaneous doping enhanced the carrier concentration of the ZnO nanopowders indicated by the higher IR reflectivity. [Copyright &y& Elsevier]

The progress of the enriched photocatalytic degradation predominantly depends on materials fabrication. In the recent times, the outcomes of nanomaterials show extraordinary efficiency due to its shape and size. In this connection, the present work concentrates on the fabrication of single digit metal oxides (CeO 2 , CuO, NiO, Mn 3 O 4 , SnO 2 and ZnO) through precipitation method. The structural information of different metal oxides (MOs) and their crystallite size were estimated via XRD analysis and their consistent results revealed that the crystalline sizes of the prepared metal oxide were exhibited in nano size. The morphology and dimension of the synthesized MOs were identified through FE-SEM and TEM techniques. The FE-SEM images were apparently defined that the actual morphology of each metal oxide expresses different dimension due to nucleation and growth process. The result of UV–vis absorption spectra was helped to identify the band gap of MOs and a suitable light for photocatalytic irradiation. Additionally, the synthesized single digit MOs nanoparticles were magnificently applied for the degradation of methyl orange and methylene blue under UV light irradiation. [ABSTRACT FROM AUTHOR]