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  • 51.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Fast synthesis, morphology transformation, structural and optical properties of ZnO nanorods grown by seed-free hydrothermal method2014In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, no 11, p. 2611-2615Article in journal (Refereed)
    Abstract [en]

    A fast and low cost seed-free hydrothermal synthesis method to synthesize zinc oxide (ZnO) nanorods with controllable morphology, size and structure has been developed. Ammonia is used to react with water to tailor the ammonium hydroxide concentration, which provides a continuous source of OH− for hydrolysis and precipitation of the final products. Hence, allowing ZnO nanorods to growth on large areas of metal (Au and Ag coated glass), p-type Si and organic flexible (PEDOT: PSS) substrates. Increasing the growth time, the morphology transforms from pencil-like to hexagonal shape rod-like morphology. Within one hour the length of the ZnO nanorods has reached almost 1 µm. The optical characteristics has shown that the grown ZnO nanorods are dominated by two emission peaks, one is in the UV range centered at 381 nm and other one with relatively high intensity appears in the visible range and centered at 630 nm. While the growth duration was increased from 2 h to 6 h, the optical band gap was observed to increase from 2.8 eV to 3.24 eV, respectively. This fast and low cost method is suitable for LEDs, UV-photodetector, sensing, photocatalytic, multifunctional devices and other optoelectronic devices, which can be fabricated on any substrates, including flexible and foldable substrates.

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  • 52.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    ZnO nanorods based piezoresistive sensor synthesized by rapid mixing hydrothermal methodManuscript (preprint) (Other academic)
    Abstract [en]

    We have successfully synthesized well-aligned, shape controlled and uniform size distribution of ZnO nanorods by using a rapid mixing hydrothermal method. The scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations showed that the ZnO nanorods grow along the c-axis with hexagonal wurtzite ZnO structure. The room temperature cathodoluminescence (CL) investigation revealed that the ZnO nanorods have optical emissions in both the UV and visible ranges and the crystal quality of the ZnO nanorods can be improved by increasing the growth duration. The well-aligned and uniform ZnO nanorods were used to fabricate efficient piezoresistive sensor. The piezoresistive sensor has demonstrated a pressure sensitivity of 0.033 KPa-1 with a fast response and recovery times within 0.088 and 0.29 s, respectively. The piezoresistive sensor has potential applications in industrial, civil and transportation fields. Furthermore, the fabricated sensor can be utilized as a very useful human-friendly interactive electronic device for load sensing.

  • 53.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Indirect Determination of Mercury Ion by Inhibition of a Glucose Biosensor Based on ZnO Nanorods2012In: Sensors, E-ISSN 1424-8220, Vol. 12, no 11, p. 15063-15077Article in journal (Refereed)
    Abstract [en]

    A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD) on ZnO nanorods (ZnO-NRs) has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG) approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA) were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS). The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 x 10(-6) mM to 0.5 x 10(-4) mM, and from 0.5 x 10(-4) mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10(-3) mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users.

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  • 54.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Fast piezoresistive sensor and UV photodetector based on Mn-doped ZnO nanorods2015In: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 9, no 1, p. 87-91Article in journal (Refereed)
    Abstract [en]

    A low cost hydrothermal synthesis method to synthesize Mn-doped ZnO nanorods (NRs) with controllable morphology and structure has been developed. Ammonia is used to tailor the ammonium hydroxide concentration, which provides a source of OH– for hydrolysis and precipitation during the growth instead of HMT. The morphological, chemical composition, structural, and electronic structure studies of the Mn-doped ZnO NRs show that the Mn-doped ZnO NRs have a hexagonal wurtzite ZnO structure along the c-axis and the Mn ions replace the Zn sites in the ZnO NRs matrix without any secondary phase of metallic manganese element and manganese oxides observed. The fabricated PEDOT:PSS/Zn0.85Mn0.15O Schottky diode based piezoresistive sensor and UV photodetector shows that the piezoresistive sensor has pressure sensitivity of 0.00617 kPa–1 for the pressure range from 1 kPa to 20 kP and 0.000180 kPa–1for the pressure range from 20 kPa to 320 kPa with relatively fast response time of 0.03 s and the UV photodetector has both relatively high responsivity and fast response time of 0.065 A/W and 2.75 s, respectively. The fabricated Schottky diode can be utilized as a very useful human-friendly interactive electronic device for mass/force sensor or UV photodetector in everyday living life. This developed device is very promising for small-size, low-cost and easy-to-customize application-specific requirements. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

  • 55.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Masood, Ansar
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Riazanova, A.
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Rao, K. V.
    Department of Materials Science, Royal Institute of Technology, Stockholm, Sweden.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Synthesis of Fe-Doped ZnO Nanorods by Rapid Mixing Hydrothermal Method and Its Application for High Performance UV Photodetector2014In: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, Vol. 2014, no 524530, p. 1-9Article in journal (Refereed)
    Abstract [en]

    We have successfully synthesized Fe-doped ZnO nanorods by a new and simple method in which the adopted approach is by using ammonia as a continuous source of OH for hydrolysis instead of hexamethylenetetramine (HMT). The energy dispersive X-ray (EDX) spectra revealed that the Fe peaks were presented in the grown Fe-doped ZnO nanorods samples and the X-ray photoelectron spectroscopy (XPS) results suggested that Fe3+ is incorporated into the ZnO lattice. Structural characterization indicated that the Fe-doped ZnO nanorods grow along the c-axis with a hexagonal wurtzite structure and have single crystalline nature without any secondary phases or clusters of FeO or Fe3O4 observed in the samples. The Fe-doped ZnO nanorods showed room temperature (300 K) ferromagnetic magnetization versus field (M-H) hysteresis and the magnetization increases from 2.5 μemu to 9.1 μemu for Zn0.99Fe0.01O and Zn0.95Fe0.05O, respectively. Moreover, the fabricated Au/Fe-doped ZnO Schottky diode based UV photodetector achieved 2.33 A/W of responsivity and 5 s of time response. Compared to other Au/ZnO nanorods Schottky devices, the presented responsivity is an improvement by a factor of 3.9.

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  • 56.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Usman Ali, Syed M.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ibupoto, Zafar H.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Potentiometric creatinine biosensor based on ZnO nanowires2012In: Journal of Nanoscience Letters, ISSN 2231-4008, Vol. 2, no 4, p. 24-24Article in journal (Refereed)
    Abstract [en]

    In the present work, we have grown well-aligned zinc oxide (ZnO) nanowires (NWs) on the surface of gold coated glass substrates by a low temperature aqueous chemical growth (ACG) approach and utilized it as a potentiometric creatinine biosensor. This was achieved by electrostatic immobilization of creatinine deiminase (CD) on the surface of the ZnO NWs followed by applying a chitosan membrane in conjunction with glutaraldehyde. This immobilization resulted in a sensitive, selective, stable, reproducible and fast creatinine biosensor. The potentiometric response of the ZnO sensor vs. Ag/AgCl reference electrode was found to be linear over a wide logarithmic concentration of creatinine electrolyte solution ranging from 1-1000 µM. The sensor illustrates good linear sensitivity slope curve of ~33.9 mV/decade along with a rapid response time of ~7 s. Furthermore, the sensor response was unaffected by normal concentrations of common interferences such as potassium, calcium, magnesium, sodium, copper ions and glucose.

  • 57. Chiragwandi, Z. G.
    et al.
    Panas, I.
    Nour, Omer
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Science and Technology.
    Willander, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Vortex rings in pure water under static electric field2006In: International Symposium on Macro- and Suparmolecular Architecture and Materials MAM-06,2006, 2006Conference paper (Other academic)
  • 58.
    Chiragwandi, ZG
    et al.
    Chalmers University of Technology and Göteborg University.
    Nour, Omer
    Chalmers University of Technology and Göteborg University.
    Willander, Magnus
    Chalmers University of Technology and Göteborg University.
    Calander, N
    Chalmers University of Technology and Göteborg University.
    dc characteristics of a nanoscale water-based transistor2003In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 83, no 25, p. 5310-5312Article in journal (Refereed)
    Abstract [en]

    We demonstrate a nanoscale water-based transistor. The presented nanoscale water-based transistor relies on the controlled modification of the pH in deionized water through the base applied electric field. The dc characteristics are presented and studied with a focus on the influence of the base applied electric field, the base electrode design, and their proximity to the sensing emitter and collector nanoelectrodes. The demonstrated water-based nanoscale device is of interest for many bioelectrical applications due to the biocompatibility and the wide usage and presence of water in biological systems.

  • 59.
    Chiragwandi, ZG
    et al.
    Göteborg University.
    Nour, Omer
    Göteborg University.
    Willander, Magnus
    Göteborg University.
    Panas, I
    Chalmers.
    Vortex rings in pure water under static external electric field2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 87, no 15Article in journal (Refereed)
    Abstract [en]

    The reproducible development of vortex rings in pure water under the action of a static external electric field is demonstrated. The phenomenon results from the electrochemical decomposition of water. Given the low conductivity of water in the absence of electrolyte, the field-driven buildup of hydroxide ions at the anode becomes essential to the proton release, which in turn is the result of the molecular O-2(g) evolution. Water recombination processes, which have protons flowing in a hydroxide background, as a key ingredient produce the phenomenon.

  • 60.
    David, Denis
    et al.
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Mancir da Silva Santana, Victor
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Bargiela, Pascal
    Royal Institute of Technology, Stockholm, Sweden.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Baldissera, Gustavo
    Royal Institute of Technology, Stockholm, Sweden.
    Persson, Clas
    Royal Institute of Technology, Stockholm, Sweden; University of Oslo, Oslo, Norway.
    Ferreira da Silva, Antonio
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Optical properties from photoelectron energy-loss spectroscopy of low-temperature aqueous chemically synthesized ZnO nanorods grown on Si2019In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 34, no 4, article id 045019Article in journal (Refereed)
    Abstract [en]

    The optical properties of zinc oxide (ZnO) nanorods (NRs) synthesized by the low-temperature aqueous chemical method on top of silicon (Si) substrate have been investigated by means of photoelectron energy loss spectroscopy (PEELS). The ZnO NRs were obtained by the low temperature aqueous chemical synthesis on top of Si substrate. The measured valence band, the dynamical dielectric functions and optical absorption of the material show a reasonable agreement when the trending and shape of the theoretical calculations are considered. A first-principle calculation based on density functional theory (DFT) was performed using the partially self-consistent GW approximation (scGW0) and compared to the experimental results. The application of these two techniques brings a new analysis of the electronic properties of this material. The experimental results regarding the density of states (DOS) obtained for the valence band using x-ray photoelectron spectroscopy (XPS) was found to be consistent with the theoretical calculated value. Due to this consistency, the same wavefunctions was then employed to calculate the dielectric function of the ZnO NRs. The experimentally extracted dielectric function was also consistent with the calculated values.

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  • 61.
    Dawi, E. A.
    et al.
    Ajman Univ, U Arab Emirates.
    Karar, A. A.
    Edith Cowan Univ, Australia.
    Mustafa, Elfatih Mohammed
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Plasmon-Enhanced Light Absorption in (p-i-n) Junction GaAs Nanowire Solar Cells: An FDTD Simulation Method Study2021In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 16, no 1, article id 149Article in journal (Refereed)
    Abstract [en]

    A finite-difference time-domain method is developed for studying the plasmon enhancement of light absorption from vertically aligned GaAs nanowire arrays decorated with Au nanoparticles. Vertically aligned GaAs nanowires with a length of 1 mu m, a diameter of 100 nm and a periodicity of 165-500 nm are functionalized with Au nanoparticles with a diameter between 30 and 60 nm decorated in the sidewall of the nanowires. The results show that the metal nanoparticles can improve the absorption efficiency through their plasmonic resonances, most significantly within the near-bandgap edge of GaAs. By optimizing the nanoparticle parameters, an absorption enhancement of almost 35% at 800 nm wavelength is achieved. The latter increases the chance of generating more electron-hole pairs, which leads to an increase in the overall efficiency of the solar cell. The proposed structure emerges as a promising material combination for high-efficiency solar cells.

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  • 62.
    Dawi, E. A.
    et al.
    Ajman Univ, U Arab Emirates.
    Mustafa, Elfatih Mohammed
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Padervand, M.
    Univ Maragheh, Iran.
    Ashames, A.
    Ajman Univ, U Arab Emirates.
    Hajiahmadi, S.
    Shahid Beheshti Univ Med Sci, Iran.
    Saleem, L.
    Univ Amsterdam, Netherlands.
    Baghernejad, M.
    Forschungszentrum Julich GmbH, Germany.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Ag/AgCl Decorated Ionic Liquid@Tantalum Pentoxide Nanostructures: Fabrication, Photocatalytic Activity, and Cytotoxicity Effects Against Human Brain Tumor Cells2023In: JOURNAL OF INORGANIC AND ORGANOMETALLIC POLYMERS AND MATERIALS, ISSN 1574-1443, Vol. 33, p. 2647-2660Article in journal (Refereed)
    Abstract [en]

    Environmental contaminants have become a major concern for human beings due to their adverse effects on drinking water quality. Heterogeneous photocatalysis has been extensively investigated as a potential strategy to minimize the consequences of as-related processes. Using a room-temperature ionic liquid-mediated co-precipitation method, Ag@AgCl nanoparticles were loaded onto tantalum pentoxide to make a plasmonic photocatalyst to remove Congo Red dye. The physicochemical properties of the photocatalysts were characterized by X-ray diffraction powder (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Diffuse Reflectance Spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM), photoluminescence (PL), and nitrogen adsorption-desorption isotherms. The results indicate that 96% of the dye was degraded within 20 min with a rate constant of 0.14 min(-1). The key radicals involved in the photocatalysis, recognized as O-2(center dot-) species, were identified by electron spin resonance (ESR) in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), as the spin trapping agent. Our findings and quenching experiments elucidates the mechanism of the charge carrier migration. The cytotoxicity activity of the nanostructures was also examined against human brain glioblastoma tumor cells for the first time. A precise analysis of the cell death pathway was conducted using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and caspase activity assays in combination with fluorescence microscopy images. The prepared nanomaterials were found to be promising candidates for treating the organic pollutants and biomedical waste effluents from academic and industrial activities.

  • 63.
    Echresh, Ahmad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Shahid Chamran University of Ahvaz, Iran.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Farbod, Mansoor
    Shahid Chamran University of Ahvaz, Iran.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Optimization and characterization of NiO thin film and the influence of thickness on the electrical properties of n-ZnO nanorods/p-NiO heterojunction2014In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 29, no 11, p. 115009-Article in journal (Refereed)
    Abstract [en]

    In this study, we report on the synthesis optimization of NiO thin film to grow preferentially along the (111) direction. The x-ray diffraction (XRD) pattern revealed that the NiO film with 200 nm thickness annealed at 600 degrees C temperature has the best preferential orientation along the (111) direction. Also, atomic force microscope (AFM) images show that the grain size of NiO increases at higher temperatures. Then, ZnO nanorods were grown on the NiO thin film with 100, 200 and 300 nm thickness grown at 600 degrees C. The XRD pattern and scanning electron microscope (SEM) images indicate that the well-aligned ZnO nanorods with hexagonal face have a preferential orientation along the c-axis (002). The current voltage measurements of the n-ZnO nanorods/p-NiO heterojunctions showed a clear rectifying behavior for all diodes. The threshold voltage of the heterojunctions was increased by increasing the thickness of the NiO thin film which was attributed to the increasing of the series resistance (R-s) of the diodes.

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  • 64.
    Echresh, Ahmad
    et al.
    Shahid Chamran University of Ahvaz, Iran.
    Chey, Chan Oeurn
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    UV photo-detector based on p-NiO thin film/n-ZnO nanorods heterojunction prepared by a simple process2015In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 632, p. 165-171Article in journal (Refereed)
    Abstract [en]

    A UV photo-detector based on p-NiO thin film/n-ZnO nanorods heterojunction was fabricated using a simple two-step fabrication process. The aqueous chemical hydrothermal and thermal evaporation methods were combined to grow the ZnO nanorods and the NiO thin film, respectively. Structural investigation indicated that well aligned ZnO nanorods with hexagonal face having a preferential orientation along the c-axis (002) have been achieved and that the NiO thin film is covering all the ZnO nanorods. X-ray photoelectron spectroscopy (XPS) was used to investigate the band alignment of the heterojunction and the valence and the conduction band offsets were determined to be 1.50 eV and 1.83 eV, respectively. The current-voltage characteristics of the p-NiO thin film/ZnO nanorods heterojunction showed a clear rectifying behavior under both dark and UV illumination conditions. The response of the heterojunction diode was excellent regarding the photocurrent generation. Although other similar heterojunction diodes demonstrated lower threshold voltage, the rectification ratio and the sensitivity of the fabricated diode were superior in comparison to other similar heterojunctions reported recently, implying the vitality of the presented two-step process. (C) 2015 Elsevier B.V. All rights reserved.

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  • 65.
    Echresh, Ahmad
    et al.
    Shahid Chamran University of Ahvaz, Iran.
    Chey, Chan Oeurn
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Light emitting diode based on n-Zn0.94M0.06O nanorods/p-GaN (M= Cd and Ni) heterojunction under forward and reverse bias2015In: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 160, p. 305-310Article in journal (Refereed)
    Abstract [en]

    In this study, we report on the improvement in the optoelectronic properties of n-ZnO nanorods/p-GaN heterojunction. This was achieved by doping the ZnO with cadmium (Cd) and nickel (Ni). The ZnO and Zn0.94M0.06O nanorods grown hydrothermally on the p-GaN substrate were used to fabricate the light emitting diodes (LEDs). Structural measurement revealed that nanorods with wurtzite structure having a preferential orientation along the (002) c-axis. The UV-vis spectra show that the optical band gap of Zn0.94M0.06O nanorods is decreased in comparison to ZnO nanorods. Electrical measurements of the fabricated LEDs show an obvious rectifying behaviour with low threshold voltage. Electroluminescence (EL) characteristics of LEDs operated at forward and reverse bias were investigated. The EL spectra under forward bias show that doping ZnO nanorods with Cd and Ni led to an intensity enhancement of the broad peak in the visible region while the blue peak originating from the p-GaN substrate remains almost unaffected. The effect of doping was to reduce the valence band offsets and consequently more hole injection has occurred leading to the observed enhancement of the broad band in the visible region. Under reverse bias all heterojunction LEDs show the blue light emission peak originating from the p-GaN substrate.

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  • 66.
    Echresh, Ahmad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Echresh, Mohammad
    Sanati Hoveizeh University, Iran.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    High photocurrent gain in NiO thin film/M-doped ZnO nanorods (M = Ag, Cd and Ni) heterojunction based ultraviolet photodiodes2016In: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 178, p. 324-330Article in journal (Refereed)
    Abstract [en]

    The thermal evaporation method has been used to deposit p-type NiO thin film, which was combined with hydrothermally grown n-type pure and M-doped ZnO nanorods (M=Ag, Cd and Ni) to fabricate a high performance p-n heterojunction ultraviolet photodiodes. The fabricated photodiodes show high rectification ratio and relatively low leakage current. The p-NiO/n-Zn0.94Ag0.06O heterojunction photo diode displays the highest photocurrent gain (similar to 1.52 x 10(4)), a photoresponsivity of similar to 4.48 x 10(3) AW(-1) and a photosensitivity of similar to 13.56 compared with the other fabricated photodiodes. The predominated transport mechanisms of the p-n heterojunction ultraviolet photodiodes at low and high applied forward bias may be recombination-tunneling and space charge limited current, respectively. (C) 2016 Elsevier B.V. All rights reserved.

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  • 67.
    Echresh, Ahmad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Shahid Chamran University of Ahvaz, Iran.
    Oeurn Chey, Chan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Tuning the emission of ZnO nanorods based light emitting diodes using Ag doping2014In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, no 19, p. 2-9Article in journal (Refereed)
    Abstract [en]

    We have fabricated, characterized, and compared ZnO nanorods/p-GaN and n-Zn0.94Ag0.06O nanorods/p-GaN light emitting diodes (LEDs). Current-voltage measurement showed an obvious rectifying behaviour of both LEDs. A reduction of the optical band gap of the Zn0.94Ag0.06O nanorods compared to pure ZnO nanorods was observed. This reduction leads to decrease the valence band offset at n-Zn0.94Ag0.06O nanorods/p-GaN interface compared to n-ZnO nanorods/p-GaN heterojunction. Consequently, this reduction leads to increase the hole injection from the GaN to the ZnO. From electroluminescence measurement, white light was observed for the n-Zn0.94Ag0.06O nanorods/p-GaN heterojunction LEDs under forward bias, while for the reverse bias, blue light was observed. While for the n-ZnO nanorods/p-GaN blue light dominated the emission in both forward and reverse biases. Further, the LEDs exhibited a high sensitivity in responding to UV illumination. The results presented here indicate that doping ZnO nanorods might pave the way to tune the light emission from n-ZnO/p-GaN LEDs.

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  • 68.
    Echresh, Ahmad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Shahid Chamran University of Ahvaz, Iran.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Farbod, Mansoor
    Shahid Chamran University of Ahvaz, Iran.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Effect of NiO intermediate layer on the optical and electrical properties of n-ZnO nanorods/p-GaAs heterojunction2015In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 119, no 3, p. 1013-1018Article in journal (Refereed)
    Abstract [en]

    ZnO nanorods were grown hydrothermally on bare and NiO-coated p-GaAs substrate to fabricate p-n heterojunctions. The NiO intermediate layer was deposited using thermal evaporation technique. The X-ray diffraction patterns revealed that ZnO nanorods grown on the bare p-GaAs do not have any preferential orientation along the c-axis, but those on the NiO-coated p-GaAs have preferential orientation along the c-axis, i.e. along the (002) direction. The scanning electron microscope images show that the NiO intermediate layer improved the uniformity and the alignment of the ZnO nanorods. Photoluminescence spectra demonstrated that increasing the thickness of NiO intermediate layer leads to improve the optical quality of the ZnO nanorods. Current-voltage characteristics showed that the presence of the NiO intermediate layer leads to increase the threshold voltage and decrease the leakage current of the n-ZnO nanorods/p-GaAs heterojunction. The energy band diagram of heterojunctions drown using Anderson model revealed that the NiO intermediate layer acts as an electron-blocking layer in the ZnO side and at the same time increases the hole injection from the GaAs to the ZnO side. Therefore, most of electron-hole pair recombination could occur at the ZnO site.

  • 69.
    Elhadi Adam, Rania Elhadi
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Synthesis of ZnO nanoparticles by co-precipitation method for solar driven photodegradation of Congo red dye at different pH2018In: PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS, ISSN 1569-4410, Vol. 32, p. 11-18Article in journal (Refereed)
    Abstract [en]

    Solar driven photocatalytic processes to remove organic pollutants from wastewater and other aqueous solutions is very important and useful due to its environmental benefits regarding sustainability aspect. In this article, we report a study on the use of bare zinc oxide (ZnO) nanoparticles (NPs) prepared by the chemical low temperature co-precipitation method and used as a catalyst to degrade the Congo red dye from aqueous solution using solar radiation. We performed the photocatalytic experiments for degradation of Congo red dye under solar radiation at different pH values. The results showed that the ZnO NPs are effective under solar radiation for degradation of Congo red dye. Even when the pH was varied down to 4 or raised to 10, the degradation was observed to be slightly improved. This result is due to the excess of radicals species, which enhance the photocatalytic process. In general, the observed degradation efficiency of the ZnO NPs is due to the deep level defects within the band gap that were introduced during the growth process of the ZnO NPs, which enhance the absorption wavelength band towards the visible light region. Recycling of the ZnO NPs for 3 successive runs have indicated the feasibility of reusing the NPs for several times. This implies that by using bare ZnO NPs an efficient approach for degradation of toxic waste can be achieved. Radical scavengers were used to evaluate the role of the radicals in the reaction mechanism.

  • 70.
    Elhadi Adam, Rania
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Mustafa, Elfatih
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Elhag, Sami
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Photocatalytic properties for different metal-oxide nanomaterials2019In: Oxide-based Materials and Devices X, SPIE , 2019, article id 1091925Conference paper (Refereed)
    Abstract [en]

    We here demonstrate the synthesis of different nanostructures, including nanoparticles, nanorods, core-shell structures,and compound metal oxide nanostructures all synthesized by a low temperature chemical process. We furtherinvestigated their photocatalytic properties for degradation of toxic waste and their photochemical efficiency for watersplitting. All the photocatalytic properties as well as the photochemical properties were utilized using sun radiation. Theresults presented indicate huge potential for the investigated processes with positive impact to energy consumption andbenefits for the environment.

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  • 71.
    Elhadi Adam, Rania
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pirhashemi, Mahsa
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. University of Mohaghegh Ardabili, Ardabil, Iran.
    Elhag, Sami
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Habibi-Yangjeh, Aziz
    University of Mohaghegh Ardabili, Ardabil, Iran.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation2019In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 15, p. 8271-8279Article in journal (Refereed)
    Abstract [en]

    Ag-based compounds are excellent co-catalyst that can enhance harvesting visible light and increase photo-generated charge carrier separation owing to its surface plasmon resonance (SPR) effect in photoelectrochemical (PEC) applications. However, the PEC performance of a ZnO/Ag/Ag2WO4 heterostructure with SPR behavior has not been fully studied so far. Here we report the preparation of a ZnO/Ag/Ag2WO4 photo-electrode with SPR behavior by a low temperature hydrothermal chemical growth method followed by a successive ionic layer adsorption and reaction (SILAR) method. The properties of the prepared samples were investigated by different characterization techniques, which confirm that Ag/Ag2WO4 was deposited on the ZnO NRs. The Ag2WO4/Ag/ZnO photo-electrode showed an enhancement in PEC performance compared to bare ZnO NRs. The observed enhancement is attributed to the red shift of the optical absorption spectrum of the Ag2WO4/Ag/ZnO to the visible region (>400 nm) and to the SPR effect of surface metallic silver (Ag0) particles from the Ag/Ag2WO4 that could generate electron–hole pairs under illumination of low energy visible sun light. Finally, we proposed the PEC mechanism of the Ag2WO4/Ag/ZnO photo-electrode with an energy band structure and possible electron–hole separation and transportation in the ZnO/Ag/Ag2WO4 heterostructure with SPR effect for water oxidation. ER

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  • 72.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain Ibupoto, Zafar
    University of Sindh Jamshoro, Pakistan.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Synthesis of Co3O4 Cotton-Like Nanostructures for Cholesterol Biosensor2015In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 8, no 1, p. 149-161Article in journal (Refereed)
    Abstract [en]

    The use of templates to assist and possess a control over the synthesis of nanomaterials has been an attractive option to achieve this goal. Here we have used sodium dodecyl sulfate (SDS) to act as a template for the low temperature synthesis of cobalt oxide (Co3O4) nanostructures. The use of SDS has led to tune the morphology, and the product was in the form of "cotton-like" nanostructures instead of connected nanowires. Moreover, the variation of the amount of the SDS used was found to affect the charge transfer process in the Co3O4. Using Co3O4 synthesized using the SDS for sensing of cholesterol was investigated. The use of the Co3O4 synthesized using the SDS was found to yield an improved cholesterol biosensor compared to Co3O4 synthesized without the SDS. The improvement of the cholesterol sensing properties upon using the SDS as a template was manifested in increasing the sensitivity and the dynamic range of detection. The results achieved in this study indicate the potential of using template assisted synthesis of nanomaterials in improving some properties, e. g., cholesterol sensing.

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  • 73.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Habit-modifying additives and their morphological consequences on photoluminescence and glucose sensing properties of ZnO nanostructures, grown via aqueous chemical synthesis2015In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 116, p. 21-26Article in journal (Refereed)
    Abstract [en]

    Generally, the anisotropic shape of inorganic nano-crystal can be influenced by one or more of different parameters i.e. kinetic energy barrier, temperature, time, and the nature of the capping molecules. Here, different surfactants acting as capping molecules were used to assist the aqueous chemical growth of zinc oxide (ZnO) nanostructures on Au coated glass substrates. The morphology, crystal quality and the photoluminescence (PL) properties of the ZnO nanostructures were investigated. The PL properties of the prepared ZnO nanostructures at room temperature showed a dominant UV luminescence peak, while the "green yellow" emissions were essentially suppressed. Moreover, the ZnO nanostructures were investigated for the development of a glucose biosensor. An adsorbed molecule has direct contribution on the glucose oxidase/ZnO/Au sensing properties. We show that the performance of a ZnO-based biosensor can be improved by tailoring the properties of the ZnO biomolecule interface through engineering of the morphology, effective surface area, and adsorption capability.

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  • 74.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Dopamine wide range detection sensor based on modified Co3O4 nanowires electrode2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 203, p. 543-549Article in journal (Refereed)
    Abstract [en]

    Ultra-thin cobalt oxide (Co3O4) nanowires grown on gold coated glass substrates by the hydrothermal chemical deposition and have been used as a wide range dopamine potentiometric sensor. An anionic surfactant ( sodium dodecylbenzenesulfonate) was used to achieve assisted growth procedure. Moreover, a polymeric membrane containing polyvinyl chloride as plasticized polymer, p-cyclodextrin as ionophore, and potassium tetrakis (4-chlorophenyl) borate as ionic additive were immobilized on the Co3O4 nanostructures through electrostatic adsorption method. X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy were used to characterize the electrodes while ultraviolet-visible absorption was used to investigate the band gap of the Co3O4 nanostructures. The structural characterization showed a cubic crystalline, pure phase, and nanowires morphology of the Co3O4. However, the morphology is altered when the surfactant concentration has been changed. The Co3O4 chemical modified electrodes were used in potentiometric measurements for dopamine in a 10(-2) M acetic acid/sodium acetate solution having a pH of 5.45. For dopamine range from 10(-9) M to 10(-2) M, the potential response of the sensor electrode was linear with a slope of 52 mV/decade. The wide range and high sensitivity of the modified Co3O4 nanowires based sensor for dopamine is attributed to the defects on the metal oxide that is dictated by the used surfactant along with the high surface area-to-volume ratio.

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  • 75.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Incorporating beta-Cyclodextrin with ZnO Nanorods: A Potentiometric Strategy for Selectivity and Detection of Dopamine2014In: Sensors, E-ISSN 1424-8220, Vol. 14, no 1, p. 1654-1664Article in journal (Refereed)
    Abstract [en]

    We describe a chemical sensor based on a simple synthesis of zinc oxide nanorods (ZNRs) for the detection of dopamine molecules by a potentiometric approach. The polar nature of dopamine leads to a change of surface charges on the ZNR surface via metal ligand bond formation which results in a measurable electrical signal. ZNRs were grown on a gold-coated glass substrate by a low temperature aqueous chemical growth (ACG) method. Polymeric membranes incorporating beta-cyclodextrin (beta-CD) and potassium tetrakis (4-chlorophenyl) borate was immobilized on the ZNR surface. The fabricated electrodes were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The grown ZNRs were well aligned and exhibited good crystal quality. The present sensor system displays a stable potential response for the detection of dopamine in 10(-2) mol.L-1 acetic acid/sodium acetate buffer solution at pH 5.45 within a wide concentration range of 1 x 10(-6) M-1 x 10(-1) M, with sensitivity of 49 mV/decade. The electrode shows a good response time (less than 10 s) and excellent repeatability. This finding can contribute to routine analysis in laboratories studying the neuropharmacology of catecholamines. Moreover, the metal-ligand bonds can be further exploited to detect DA receptors, and for bio-imaging applications.

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  • 76.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties2016In: Sensors, E-ISSN 1424-8220, Vol. 16, no 2Article in journal (Refereed)
    Abstract [en]

    In this paper, we show that the possibility of using polyethylene glycol (EG) as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs). EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS) suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL) and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10(-6) M to 10(-3) M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

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  • 77.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Tordera, Daniel
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Deydier, T
    Department of Material Engineering, University of Toulon, FR-83041 Toulon, France .
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    LiU, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Khranovskyy, Volodymyr
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Low-temperature growth of polyethylene glycol-doped BiZn2VO6 nanocompounds with enhanced photoelectrochemical properties2017In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 3, p. 1112-1119Article in journal (Refereed)
    Abstract [en]

    We demonstrate scalable, low-cost and low-temperature (<100 °C) aqueous chemical growth of bismuth–zinc vanadate (BiZn2VO6) nanocompounds by BiVO4 growth on ZnO nanobelts (NBs). The nanocompounds were further doped with polyethylene glycol (PEG) to tune the electronic structure of the materials, as a means to lower the charge carrier recombination rate. The chemical composition, morphology, and detailed nanostructure of the BiZn2VO6 nanocompounds were characterized. They exhibit rice-like morphology, are highly dense on the substrate and possess a good crystalline quality. Photoelectrochemical characterization in 0.1 M lithium perchlorate in carbonate propylene shows that BiZn2VO6 nanocompounds are highly suitable as anodes for solar-driven photoelectrochemical applications, providing significantly better performance than with only ZnO NBs. This performance could be attributed to the heterogeneous catalysis effect at nanocompound and ZnO NB interfaces, which have enhanced the electron transfer process on the electrode surface. Furthermore, the charge collection efficiency could be significantly improved through PEG doping of nanocompounds. The photocurrent density of PEG-doped BiZn2VO6 nanocompounds reached values of 2 mA cm−2 at 1.23 V (vs. Ag/AgCl), over 60% larger than that of undoped BiZn2VO6 nanocompounds. Photoluminescence emission experiments confirmed that PEG plays a crucial role in lowering the charge carrier recombination rate. The presented BiZn2VO6 nanocompounds are shown to provide highly competitive performance compared with other state-of-the art photoelectrodes.

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  • 78.
    Elsharif Zainelabdin, Ahmed
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Amin, Gul
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zaman, Siama
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Metal Oxide Nanostructures and White Light Emission2012In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 8263, no 82630NArticle in journal (Refereed)
    Abstract [en]

    We report on white light emission from zinc oxide nanostructures chemically grown on paper substrates. The effect of the growth solution pH on the morphology is discussed. The light emission form light emitting diodes based on ZnO nanorods/organic polymer hybrids on paper substrate is presented. Further copper oxide was grown on the walls of zinc oxide nanorods and the optical properties were investigated.

  • 79.
    Fakhar-e-Alam, M.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Kishwar, S.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Khan, Y.
    Pakistan Institute for Engineering and Applied Science.
    Siddique, M.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Atif, M.
    Pakistan Institute for Engineering and Applied Science.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Tumoricidal Effects of Nanomaterials in HeLa Cell Line2011In: Laser physics, ISSN 1054-660X, E-ISSN 1555-6611, Vol. 21, no 11, p. 1978-1988Article in journal (Refereed)
    Abstract [en]

    The current study exhibits the cellular response of HeLa (cervical cancer) cells to metal oxides ultrafine nanomaterials e.g. manganese dioxide nanowires (MnO(2) NRs), iron oxide nanoparticles (Fe(2)O(3) NPs) and zinc oxide nanorods (ZnO NRs) as bare and as conjugated with photosensitizers. For cytotoxic evaluations, the cellular morphology, (MTT) assay, reactive oxygen species (ROS) production were used for cases with and without photo sensitizer as well illuminated with UV-visible laser exposed conditions. Three different photosensitizers were tested. These are 5-aminolevulinic acid (5-ALA), Photofrin (R), and protoporphyrin dimethyl ester (PPDME). Significant loss in cell viability was noted with 100-500 mu g/ml in bare and conjugated forms of the metal oxides used. The effect was insignificant with lower concentrations (0.05-50 mu g/ml). While notable anticancer effect of 5-ALA under 30 J/cm(2) of diode laser irradiation was noted as compared to other photo sensitizer. By increasing the UV irradiation time of labeled cells, generation of ROS was observed, indicating the possibility of achieving efficient photodynamic therapy (PDT).

  • 80.
    Fakhar-E-Alam, M.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. GC University, Pakistan.
    Kishwer, Sultana
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Abbas, Najeeb
    GC University, Pakistan.
    Atif, M.
    King Saud University, Saudi Arabia; National Institute Laser and Optron, Pakistan.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Amin, Nasir
    GC University, Pakistan.
    Farooq, W. A.
    King Saud University, Saudi Arabia.
    Anticancer effects of nanometallic oxides and their ligands with photosensitizers in osteosarcoma cells2015In: Journal of Optoelectronics and Advanced Materials, ISSN 1454-4164, E-ISSN 1841-7132, Vol. 17, no 11-12, p. 1808-1815Article in journal (Refereed)
    Abstract [en]

    We studied the cytotoxic effects in Osteosarcoma (U2OS) cells to different nanosized metallic oxides e.g. zinc oxide nanowires (ZnO-NRs), manganese di-oxide nanowires (MnO2 NWs), ferric oxide nanoparticles (Fe2O3 NPs) individually and their connplexed forms with photosensitizers photofrin (R), 5-Aminolevulinic acid (5-ALA), and protoporphyrin IX (Pp IX). Cellular toxicity was assayed by cellular morphology, reactive oxygen species (ROS) detection, MTT assay under ultraviolet (UV), visible light and laser exposed conditions. Prominent cell death with above cited nanomaterials in their complexed forms with Photosensitizer was observed in labeled U2OS cells. This cell death might be due to their synergetic effect via the release of singlet oxygen species in Osteosarcoma cells showing their anticancer-cell effects.

  • 81.
    Faraz, Sadia Muniza
    et al.
    Department of Electronic Engineering, NED University of Engineering and Technology, 75270, Karachi, Pakistan.
    Alvi, Muhammed Naveed
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ul Wahab, Qamar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Annealing Effects on Electrical and Optical Properties of N-ZnO/P-Si Heterojunction Diodes2011In: Advanced Materials Research Vol. 324 (2011) pp 233-236, Trans Tech Publications Inc., 2011, p. 233-236Conference paper (Refereed)
    Abstract [en]

    The effects of post fabrication annealing on the electrical characteristics of n-ZnO/p-Si heterostructure are studied. The nanorods of ZnO are grown by aqueous chemical growth (ACG) technique on p-Si substrate and ohmic contacts of Al/Pt and Al are made on ZnO and Si. The devices are annealed at 400 and 600 oC in air, oxygen and nitrogen ambient. The characteristics are studied by photoluminescence (PL), current–voltage (I-V) and capacitance - voltage (C-V) measurements. PL spectra indicated higher ultraviolet (UV) to visible emission ratio with a strong peak of near band edge emission (NBE) centered from 375-380 nm and very weak broad deep-level emissions (DLE) centered from 510-580 nm. All diodes show typical non linear rectifying behavior as characterized by I-V measurements. The results indicated that annealing in air and oxygen resulted in better electrical characteristics with a decrease in the reverse current.

  • 82.
    Faraz, Sadia Muniza
    et al.
    NED Univ Engn & Technol, Pakistan.
    Jafri, Syed Riaz Un Nabi
    NED Univ Engn & Technol, Pakistan.
    Khan, Hashim Raza
    NED Univ Engn & Technol, Pakistan.
    Shah, Wakeel
    NED Univ Engn & Technol, Pakistan.
    Alvi, Naveed ul Hassan
    RISE Res Inst Sweden, Sweden.
    Wahab, Qamar Ul
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Effect of annealing temperature on the interface state density of n-ZnO nanorod/p-Si heterojunction diodes2021In: OPEN PHYSICS, ISSN 2391-5471, Vol. 19, no 1, p. 467-476Article in journal (Refereed)
    Abstract [en]

    The effect of post-growth annealing treatment of zinc oxide (ZnO) nanorods on the electrical properties of their heterojunction diodes (HJDs) is investigated. ZnO nanorods are synthesized by the low-temperature aqueous solution growth technique and annealed at temperatures of 400 and 600 degrees C. The as-grown and annealed nanorods are studied by scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. Electrical characterization of the ZnO/Si heterojunction diode is done by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. The barrier height (phi(B)), ideality factor (n), doping concentration and density of interface states (NSS) are extracted. All HJDs exhibited a nonlinear behavior with rectification factors of 23, 1,596 and 309 at +/- 5 V for the as-grown, 400 and 600 degrees C-annealed nanorod HJDs, respectively. Barrier heights of 0.81 and 0.63 V are obtained for HJDs of 400 and 600 degrees C-annealed nanorods, respectively. The energy distribution of the interface state density has been investigated and found to be in the range 0.70 x 10(10) to 1.05 x 10(12) eV/cm(2) below the conduction band from E-C = 0.03 to E-C = 0.58 eV. The highest density of interface states is observed in HJDs of 600 degrees C annealed nanorods. Overall improved behavior is observed for the heterojunctions diodes of 400 degrees C-annealed ZnO nanorods.

  • 83.
    Faraz, Sadia Muniza
    et al.
    NED Univ Engn & Technol, Pakistan.
    Jafri, Syed Riaz un Nabi
    NED Univ Engn & Technol, Pakistan.
    Tajvar, Zarreen
    NED Univ Engn & Technol, Pakistan.
    Alvi, Naveed ul Hassan
    RISE Res Inst Sweden, Sweden.
    Wahab, Qamar Ul
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Effect of Annealing Atmosphere on the Diode Behaviour of ZnO/Si Heterojunction2021In: Elektronika ir Elektrotechnika, ISSN 1392-1215, Vol. 27, no 4, p. 49-54Article in journal (Refereed)
    Abstract [en]

    The effect of thermal annealing atmosphere on the electrical characteristics of Zinc oxide (ZnO) nanorods/p-Silicon (Si) diodes is investigated. ZnO nanorods are grown by low-temperature aqueous solution growth method and annealed in Nitrogen and Oxygen atmosphere. As-grown and annealed nanorods are studied by scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. Electrical characteristics of ZnO/Si heterojunction diodes are studied by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. Improvements in rectifying behaviour, ideality factor, carrier concentration, and series resistance are observed after annealing. The ideality factor of 4.4 for as-grown improved to 3.8 and for Nitrogen and Oxygen annealed improved to 3.5 nanorods diodes. The series resistances decreased from 1.6 to 1.8 times after annealing. An overall improved behaviour is observed for oxygen annealed heterojunction diodes. The study suggests that by controlling the ZnO nanorods annealing temperatures and atmospheres the electronic and optoelectronic properties of ZnO devices can be improved.

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  • 84.
    Faraz, Sadia Muniza
    et al.
    NED Univ Engn and Technol, Pakistan.
    Shah, Wakeel
    NED Univ Engn and Technol, Pakistan.
    Alvi, Naveed
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Wahab, Qamar Ul
    Univ Technol, Pakistan.
    Electrical Characterization of Si/ZnO Nanorod PN Heterojunction Diode2020In: Advances in Condensed Matter Physics, ISSN 1687-8108, E-ISSN 1687-8124, Vol. 2020, article id 6410573Article in journal (Refereed)
    Abstract [en]

    The electrical characterization of p-Silicon (Si) and n-Zinc oxide (ZnO) nanorod heterojunction diode has been performed. ZnO nanorods were grown on p-Silicon substrate by the aqueous chemical growth (ACG) method. The SEM image revealed high density, vertically aligned hexagonal ZnO nanorods with an average height of about 1.2 mu m. Electrical characterization of n-ZnO nanorods/p-Si heterojunction diode was done by current-voltage (I-V), capacitance-voltage (C-V), and conductance-voltage (G-V) measurements at room temperature. The heterojunction exhibited good electrical characteristics with diode-like rectifying behaviour with an ideality factor of 2.7, rectification factor of 52, and barrier height of 0.7 V. Energy band (EB) structure has been studied to investigate the factors responsible for small rectification factor. In order to investigate nonidealities, series resistance and distribution of interface state density (N-SS) below the conduction band (CB) were extracted with the help of I-V and C-V and G-V measurements. The series resistances were found to be 0.70, 0.73, and 0.75 K omega, and density distribution interface states from 8.38 x 10(12) to 5.83 x 10(11) eV(-1) cm(-2) were obtained from 0.01 eV to 0.55 eV below the conduction band.

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  • 85.
    Fulati, Alimujiang
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Usman Ali, Syed M
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Riaz, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Amin, Gul
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Miniaturized pH Sensors Based on Zinc Oxide Nanotubes/Nanorods2009In: SENSORS, ISSN 1424-8220, Vol. 9, no 11, p. 8911-8923Article in journal (Refereed)
    Abstract [en]

    ZnO nanotubes and nanorods grown on gold thin film were used to create pH sensor devices. The developed ZnO nanotube and nanorod pH sensors display good reproducibility, repeatability and long-term stability and exhibit a pH-dependent electrochemical potential difference versus an Ag/AgCl reference electrode over a large dynamic pH range. We found the ZnO nanotubes provide sensitivity as high as twice that of the ZnO nanorods, which can be ascribed to the fact that small dimensional ZnO nanotubes have a higher level of surface and subsurface oxygen vacancies and provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods, thus affording the ZnO nanotube pH sensor a higher sensitivity. Experimental results indicate ZnO nanotubes can be used in pH sensor applications with improved performance. Moreover, the ZnO nanotube arrays may find potential application as a novel material for measurements of intracellular biochemical species within single living cells.

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  • 86.
    Hatamie, Amir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. Shahid Chamran University, Iran.
    Echresh, Ahmad
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. Shahid Chamran University, Iran.
    Zargar, Behrooz
    Shahid Chamran University, Iran.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Fabrication and characterization of highly-ordered Zinc Oxide nanorods on gold/glass electrode, and its application as a voltammetric sensor2015In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 174, p. 1261-1267Article in journal (Refereed)
    Abstract [en]

    A novel voltammetric determination of amoxicillin (AMX) sensor has been fabricated, using zinc oxide nanorods (ZnO NRs) grown directly on gold/glass electrode. To prepare an electrode, ZnO NRs were directly grown on Au sputtered (thickness: 100 nm) glass substrate (gold/glass electrode) with hydrothermal method. The directly synthesized ZnO NRs on the electrode expressively increases NRs attachment vertically, and increase its specific surface area. ZnO NRs/gold/glass electrode was characterized by field emission electron microscopy (FESEM), X-ray diffractometer (XRD) techniques, and this study has shown that the grown nanostructures are highly dense, uniform, and exhibited good crystal quality. The performance of the electrode was characterized with cyclic voltammetry (alpha) and chronoamperometry (CA). The parameters of charge transfer coefficient (k(h)), diffusion coefficient (D), electrode surface area (A), and catalytic rate constant (4) were determined, and the results were studied. The electro catalytic current of AMX was found to have a linear relation to concentration over the range of 5 x 10(-6) M - 250 x 10(-6) M (n=6). The good performance of the electrode is due to more immobilization on the well-aligned ZnO NRs arrays, and direct electron conduction between the ZnO NRs and the electrodes. Further, the sensor also showed a promising application for detecting AMX in capsule sample. The ease of fabrication, acceptable stability, and low cost of the modified electrode are the promising features of the proposed sensor.

  • 87.
    Hatamie, Amir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Shahid Chamran University, Iran.
    Khan, Azam
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. NED University of Engn and Technology, Pakistan.
    Golabi, Mohsen
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Mak, Wing Cheung
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Sadollah Khani, Azar
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Shahid Chamran University, Iran.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Zargar, Behrooz
    Shahid Chamran University, Iran.
    Bano, Sumaira
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Zinc Oxide Nanostructure-Modified Textile and Its Application to Biosensing, Photocatalysis, and as Antibacterial Material2015In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, no 39, p. 10913-10921Article in journal (Refereed)
    Abstract [en]

    Recently, one-dimensional nanostructures with different morphologies (such as nanowires, nanorods (NRs), and nanotubes) have become the focus of intensive research, because of their unique properties with potential applications. Among them, zinc oxide (ZnO) nanomaterials has been found to be highly attractive, because of the remarkable potential for applications in many different areas such as solar cells, sensors, piezoelectric devices, photodiode devices, sun screens, antireflection coatings, and photocatalysis. Here, we present an innovative approach to create a new modified textile by direct in situ growth of vertically aligned one-dimensional (1D) ZnO NRs onto textile surfaces, which can serve with potential for biosensing, photocatalysis, and antibacterial applications. ZnO NRs were grown by using a simple aqueous chemical growth method. Results from analyses such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the ZnO NRs were dispersed over the entire surface of the textile. We have demonstrated the following applications of these multifunctional textiles: (1) as a flexible working electrode for the detection of aldicarb (ALD) pesticide, (2) as a photo catalyst for the degradation of organic molecules (i.e., Methylene Blue and Congo Red), and (3) as antibacterial agents against Escherichia coli. The ZnO-based textile exhibited excellent photocatalytic and antibacterial activities, and it showed a promising sensing response. The combination of sensing, photo catalysis, and antibacterial properties provided by the ZnO NRs brings us closer to the concept of smart textiles for wearable sensing without a deodorant and antibacterial control. Perhaps the best known of the products that is available in markets for such purposes are textiles with silver nanoparticles. Our modified textile is thus providing acceptable antibacterial properties, compared to available commercial modified textiles.

  • 88.
    Hezam, F. A.
    et al.
    Taiz Univ, Yemen; Univ Khartoum, Sudan.
    Khalifa, Nodar O.
    Sudan Univ Sci & Technol, Sudan.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Mustafa, M. A.
    Univ Khartoum, Sudan.
    Synthesis and magnetic properties of Ni0.5MgxZn0.5-xFe2O4 (0.0 <= x <= 0.5) nanocrystalline spinel ferrites2021In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 257, article id 123770Article in journal (Refereed)
    Abstract [en]

    In this work, structural and magnetic properties of Ni0.5Mg Zn0.5-xFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) nanocrystalline ferrites synthesized via the co-precipitation method are reported. The ferrites are found to be at the nano-scale with sizes below 30 nm and seem porous in their general appearance. The structural properties were investigated using X-ray and Infrared (IR) spectra. X-ray Diffraction (XRD) patterns have been refined using the Rietveld method to find the lattice parameters. It was found that all these ferrites are a single-phase cubic spinel related structure belonging to the Fd-3m space group. Further, the positions, occupancy and Wyckoff s cationic position of the ions, in addition the lattice constant (a), the crystallite size (D) and the micro-strain of the composites have been analyzed and found to be affected by the variation of the Mg2+ ions concentration. The Vibrating Sample Magnetometer (VSM) technique showed that these nanoparticles are superparamagnetic with approximately impermanent magnetization of relatively high values. It was also found that the magnetization values of the Ni0.5MgxZn0.5-xFe2O4 (0.0 &lt;= x &lt;= 0.5) system increase with the existence of the Mg2+ and the Zn2+ contents together (at x = 0.1, 0.2, 0.3, 0.4) due to the increase in the super exchange interaction happening between the Fe3+ and the Ni2+ ions resulting from the occupation of the Mg2+ and the Zn2+ ions (nonmagnetic) to exclusively the A-sites as indicated by the Rietvelds structural analysis. These composites are expected to be promising for biomedical applications due to their superparamagnetic property below 30 nm.

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  • 89.
    Hezam, F. A.
    et al.
    Taiz Univ, Yemen; Univ Khartoum, Sudan.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Mustafa, M. A.
    Univ Khartoum, Sudan.
    Synthesis, structural, optical and magnetic properties of NiFe2O4/MWCNTs/ZnO hybrid nanocomposite for solar radiation driven photocatalytic degradation and magnetic separation2020In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 592, article id 124586Article in journal (Refereed)
    Abstract [en]

    Novel multifunctional NiFe2O4/MWCNTs/ZnO hybrid nanocomposite has been successfully synthesized via the hydrothermal and the co-precipitation methods at 210 degrees C and 90 degrees C, respectively, to be used as a solar radiation driven photocatalytic material. The hybrid nanocomposite exhibits enhanced photocatalytic activity compared to NiFe2O4 and ZnO for decolorization of Methylene Blue (MB) dye -as a model pollutant - from aqueous solutions under solar radiation. Different complementary analytical tools were used to investigate the structural, optical and magnetic properties of the photocatalyst which possess good light response ability, photocatalytic stability, magnetic separation performance and reproducibility. The results from optical degradation confirmed the synergistic effect between the NiFe2O4, the ZnO and the MWCNTs. Suppressed recombination of electron-hole pairs mean more efficient charge separation and enhanced photocatalytic activity. The apparent rate constant (k(app)) of the MB decolorization for a duration of 300 min using NiFe2O4/MWCNTs/ZnO, NiFe2O4 and ZnO photocatalysts were found to be 0.00438 min(-1), 4.12857E(-4) min(-1) and 0.002 min(-1) respectively. The removal efficiency was also investigated for different pH values. Due to the magnetic properties of the nanocomposite, it was possible to separate it after degradation experiments and hence re-usability is possible. In view of the enhanced solar radiation driven photodegradation, the present composite can present a robust alternative as a solar radiation driven photocatalyst.

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  • 90.
    Hezam, F. A.
    et al.
    Taiz Univ, Yemen; Univ Khartoum, Sudan.
    Rajeh, A.
    Amran Univ, Yemen.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Mustafa, M. A.
    Univ Khartoum, Sudan; Univ Khartoum, Sudan.
    Synthesis and physical properties of spinel ferrites/MWCNTs hybrids nanocomposites for energy storage and photocatalytic applications2020In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 596, article id 412389Article in journal (Refereed)
    Abstract [en]

    NiFe2O4, NiFe2O4/MWCNTs, CoFe2O4 and CoFe2O4/MWCNTs nanocomposites were synthesized via the hydrothermal method. XRD, FT-IR, SEM and TEM techniques have been used to investigate the structural properties. CoFe2O4/MWCNTs has a good morphology with small sizes compared to NiFe2O4/MWCNTs. UV-vis. DRS analysis showed that the nanocomposites have high absorbance of irradiation in the whole range of the wavelengths (200-900 nm). The optical energy gaps of the nanocomposites have been calculated. Using VSM technique, NiFe2O4 and NiFe2O4/MWCNTs exhibited super-paramagnetism at room temperature, while CoFe2O4 and CoFe2O4/MWCNTs exhibited ferromagnetism with saturation magnetization of 37.8, 25.5, 66.46 and 51.49 emu/g, respectively. The AC conductivity measurements for NiFe2O4 and CoFe2O4 NPs revealed an increase in conductivity with the addition of MWCNTs as well as the dielectric measurements. The structural and electrical properties of CoFe2O4/MWCNTs make it of potential for capacitive storage and optoelectronic devices. Promising magnetic-optical properties can be utilized for developing recyclable photocatalytic applications.

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  • 91.
    Hussain, I.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Hussain, S
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Study of intrinsic white light emission and its components from ZnO-nanorods/p-polymer hybrid junctions grown on glass substrates2011In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 46, no 23, p. 7437-7442Article in journal (Refereed)
    Abstract [en]

    We report white-light luminescence from ZnO-organic hybrid light emitting diodes grown on glass substrate by low temperature aqueous chemical growth. The configuration used for the hybrid white light emitting diodes (HWLEDs) consists of two-layers of polymers (PEDOT:PSS/PFO) on glass with top ZnO nanorods. Electroluminescence spectra of the HWLEDs demonstrate the combination of emission bands arising from the radiative recombination in polymer and ZnO nanorods. In order to distinguish emission bands we used a Gaussian function to simulate the experimental data. The emitted white light was found to be the superposition of a blue line at 454 nm, a green emission at 540 nm, orange line at 617 nm, and finally a red emission at 680 nm. The transitions causing these emissions are identified and discussed in terms of the energy band diagram of the hybrid junction. Color coordinates measurement of the WLED reveals that the emitted light has a white impression with 70 color rendering index and correlated color temperature 5500 K. Comparison between ITO and aluminum top contacts and its influence on the emitted intensity is also discussed.

  • 92.
    Hussain, I
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Soomro, Muhammad Yousuf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Interface trap characterization and electrical properties of Au-ZnO nanorod Schottky diodes by conductance and capacitance methods2012In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 112, no 6, p. 064506-Article in journal (Refereed)
    Abstract [en]

    Schottky diodes with Au/ZnO nanorod (NR)/n-SiC configurations have been fabricated and their interface traps and electrical properties have been investigated by current-voltage (I-V), capacitance-voltage (C-V), capacitance-frequency (C-f), and conductance-frequency (G(p)/omega-omega) measurements. Detailed and systematic analysis of the frequency-dependent capacitance and conductance measurements was performed to extract the information about the interface trap states. The discrepancy between the high barrier height values obtained from the I-V and the C-V measurements was also analyzed. The higher capacitance at low frequencies was attributed to excess capacitance as a result of interface states in equilibrium in the ZnO that can follow the alternating current signal. The energy of the interface states (E-ss) with respect to the valence band at the ZnO NR surface was also calculated. The densities of interface states obtained from the conductance and capacitance methods agreed well with each other and this confirm that the observed capacitance and conductance are caused by the same physical processes, i.e., recombination-generation in the interface states. (C) 2012 American Institute of Physics.

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  • 93.
    Hussain, I.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Yousuf Soomro, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Systematic study of interface trap and barrier inhomogeneities using I-V-T characteristics of Au/ZnO nanorods Schottky diode2013In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, no 23Article in journal (Refereed)
    Abstract [en]

    This paper presents in-depth analysis of I-V-T characteristics of Au/ZnO nanorods Schottky diodes. The temperature dependence I-V parameters such as the ideality factor and the barrier heights have been explained on the basis of inhomogeneity. Detailed and systematic analysis was performed to extract information about the interface trap states. The ideality factor decreases, while the barrier height increases with increase of temperature. These observations have been ascribed to barrier inhomogeneities at the Au/ZnO nanorods interface. The inhomogeneities can be described by the Gaussian distribution of barrier heights. The effect of tunneling, Fermi level pinning, and image force lowering has contribution in the barrier height lowering. The recombination-tunneling mechanism is used to explain the conduction process in Au/ZnO nanorods Schottky diodes. The ionization of interface states has been considered for explaining the inhomogeneities.

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  • 94.
    Hussain Ibupoto, Zafar
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Usman Ali, Syed
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Chey, C O
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Khun, K
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Selective zinc ion detection by functionalised ZnO nanorods with ionophore2011In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 110, no 10, p. 104702-Article in journal (Refereed)
    Abstract [en]

    In this paper, highly dense and well aligned single-crystal zinc oxide nanorods were grown along the c-axis on a gold coated glass substrate using a low temperature aqueous chemical growth approach. The prepared ZnO nanorods were functionalized with plastic membrane coatings containing specific ionophore (12-crown-4) which is highly selective to zinc ions (Zn(+2)). The electrochemical response of the sensor was found to be linear over a relatively wide logarithmic concentration range from 1 mu M to 100mM. The proposed sensor showed a good linearity with a high sensitivity of similar to 35 mV/decade for sensing Zn(+2) ions. A fast response time of less than 5 s with a good selectivity, repeatability, reproducibility, and negligible response to common interferents ions such as calcium (Ca(2+)), magnesium (Mg(2+)), or potassium (K(+)), and iron (Fe(+3)) and copper (Cu(+2)) was also demonstrated. Moreover, the proposed sensor showed good stoichiometric results for potentiometric titration.

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  • 95.
    Hussain, Ijaz
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Hussain, Sajjad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Soomro, Muhammad Yousuf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Study of the Distribution of Radiative Defects and Reabsorption of the UV in ZnO Nanorods-Organic Hybrid White Light Emitting Diodes (LEDs)2011In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 4, no 7, p. 1260-1270Article in journal (Refereed)
    Abstract [en]

    In this study, the low temperature aqueous chemical growth (ACG) method was employed to synthesized ZnO nanorods to process-organic hybrid white light emitting diodes (LEDs) on glass substrate. Electroluminescence spectra of the hybrid white LEDs demonstrate the combination of emission bands arising from radiative recombination of the organic and ZnO nanorods (NRs). Depth resolved luminescence was used for probing the nature and spatial distribution of radiative defects, especially to study the re-absorption of ultraviolet (UV) in this hybrid white LEDs structure. At room temperature the cathodoluminescence (CL) spectra intensity of the deep band emission (DBE) is increased with the increase of the electron beam penetration depth due to the increase of defect concentration at the ZnO NRs/Polyfluorene (PFO) interface and probably due to internal absorption of the UV. A strong dependency between the intensity ratio of the UV to the DBE bands and the spatial distribution of the radiative defects in ZnO NRs has been found. The comparison of the CL spectra from the PFO and the ZnO NRs demonstrate that PFO has a very weak violet-blue emission band, which confirms that most of the white emission components originate from the ZnO NRs.

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    Material
  • 96.
    Hussain, Mushtaque
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khan, Azam
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Comparative Study of Energy Harvesting from ZnO Nanorods Using Different Flexible Substrates2014In: Energy Harvesting and Systems, ISSN 2329-8774, Vol. 1, no 1-2, p. 19-26Article in journal (Refereed)
    Abstract [en]

    The step toward the fabrication of nanodevices with low cost and improved performance is of high demand; therefore, in the present study, different flexible substrates like common paper, textile fabric, plastic and aluminum foil have been utilized to harvest electrical energy. ZnO nanorods (NRs) were grown by using lowtemperature aqueous chemical growth method. The obtained ZnO NRs were highly dense, well aligned, uniformly distributed over the substrates and exhibited good crystal quality. The structural study was carried out by using X-ray powder diffraction and scanning electron microscopy. The piezoelectric properties of ZnO NRs were investigated by the help of an atomic force microscope using contact mode. The measurements of generated piezoelectricity were around 16.2 mV, 23.2 mV, 38.5 mV and 43.3 mV for common paper, textile fabric, plastic and aluminum foil, respectively. This investigation is an important step in order to study the effect of different substrates influencing the magnitude of the output voltage under identical growth and measurement conditions. We expect that this study will help identify the most suitable flexible substrate for harvesting energy. It also offers a promising alternative powering source for the next generation nanodevices using non-conventional substrates like aluminum foil. Moreover, the use of aluminum foil as flexible and low cost substrate may pave the way to develop devices in different fields including energy harvesting.

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    Comparative Study of Energy Harvesting from ZnO Nanorods Using Different Flexible Substrates
  • 97.
    Hussain, Mushtaque
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ali Abbasi, Mazhar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain Ibupoto, Zafar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    The improved piezoelectric properties of ZnO nanorods with oxygen plasma treatment on the single layer graphene coated polymer substrate2014In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, no 2, p. 455-459Article in journal (Refereed)
    Abstract [en]

    The step towards the fabrication of nanodevices with improved performance is of high demand; therefore, in this study, oxygen plasma treated ZnO nanorods based piezoelectric nanogenerator is developed on the single layer graphene coated PET flexible polymer substrate. ZnO nanorods on the single layer graphene are grown by hydrothermal growth method and the structural study is carried out by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The piezoelectric properties of ZnO nanorods with and without plasma treatment were investigated by atomic force microscopy (AFM). The oxygen plasma treated sample of ZnO nanorods showed significant increase in the piezoelectric potential which could be due to the decrease in the defects levels in the ZnO and also increase in the mechanical properties of ZnO nanorods. Furthermore X-ray photoelectron spectroscopy (XPS) confirms that the filling of vacancies by oxygen in the matrix of ZnO using oxygen plasma treatment has gave an enhanced piezoelectric potential compared to the sample of ZnO nanorods not treated with oxygen plasma. In addition to XPS experiment, cathodoluminescence (CL) technique was used for the determination of defect level in the ZnO nanorods after the treatment of oxygen plasma and the obtained information supported the XPS data of oxygen plasma treatment sample by showing the decreased level of defect levels in the prepared sample. From the XPS and CL studies, it is observed that the defect level has significant influence on the piezoelectric potential of the ZnO nanostructures.

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  • 98.
    Hussain, Mushtaque
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics, Electronics and Mathematics. Linköping University, Faculty of Science & Engineering.
    Correction: Effect of anions on the morphology of Co3O4 nanostructures grown by hydrothermal method and their pH sensing application (vol 717, pg 78, 2014)2021In: JOURNAL OF ELECTROANALYTICAL CHEMISTRY, ISSN 1572-6657, Vol. 880, article id 114783Article in journal (Other academic)
    Abstract [en]

    n/a

  • 99.
    Hussain, Mushtaque
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Synthesis of Three Dimensional Nickel Cobalt Oxide Nanoneedles on Nickel Foam, Their Characterization and Glucose Sensing Application2014In: Sensors, E-ISSN 1424-8220, Vol. 14, no 3, p. 5415-5425Article in journal (Refereed)
    Abstract [en]

    In the present work, NiCo2O4 nanostructures are fabricated in three dimensions (3D) on nickel foam by the hydrothermal method. The nanomaterial was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The nanostructures exhibit nanoneedle-like morphology grown in 3D with good crystalline quality. The nanomaterial is composed of nickel, cobalt and oxygen atoms. By using the favorable porosity of the nanomaterial and the substrate itself, a sensitive glucose sensor is proposed by immobilizing glucose oxidase. The presented glucose sensor has shown linear response over a wide range of glucose concentrations from 0.005 mM to 15 mM with a sensitivity of 91.34 mV/decade and a fast response time of less than 10 s. The NiCo2O4 nanostructures-based glucose sensor has shown excellent reproducibility, repeatability and stability. The sensor showed negligible response to the normal concentrations of common interferents with glucose sensing, including uric acid, dopamine and ascorbic acid. All these favorable advantages of the fabricated glucose sensor suggest that it may have high potential for the determination of glucose in biological samples, food and other related areas.

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  • 100.
    Hussain, Mushtaque
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Effect of anions on the morphology of Co3O4 nanostructures grown by hydrothermal method and their pH sensing application2014In: Journal of Electroanalytical Chemistry, ISSN 1572-6657, Vol. 717-718, p. 78-82Article in journal (Refereed)
    Abstract [en]

    A fast, reliable, accurate, precise and sensitive pH sensor device is highly demanding for the monitoring of pH in biological, clinical and food industry samples. In this research work, the effect of anions on the morphology of cobalt oxide (Co3O4) nanostructures is investigated using low temperature chemical approach for the growth. Different anions have shown visible effect on the morphology of Co3O4 nanostructures. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy techniques were used for the material characterization. This study has shown highly dense, uniform and good crystal quality of fabricated Co3O4 nanostructures. The nanostructures obtained from the cobalt chloride were used for the development of potentiometric pH sensor electrode. The pH sensor electrode showed excellent linearity and close to Nernstian response for the pH range of 3-13 with a sensitivity of -58.45 mV/pH. Moreover, the proposed sensor showed a fast response time of 53 s, and acceptable reducibility and repeatability. The highly sensitive and a fast time response of the proposed sensor device indicate its potential application for the monitoring of pH from real samples including biological fluids.

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    Effect of anions on the morphology of Co3O4 nanostructures grown by hydrothermal method and their pH sensing application
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