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  • 1.
    Amin, Gul
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Asif, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Elsharif Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    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.
    CuO Nanopetals Based Electrochemical Sensor for Selective Ag+ Measurements2012In: SENSOR LETTERS, ISSN 1546-198X, Vol. 10, no 3-4, p. 754-759Article in journal (Refereed)
    Abstract [en]

    The electrochemical sensing activity of cupric oxide (CuO) nanopetals was investigated for the detection of silver (I) ions (Ag+). The CuO nanopetals were synthesized on a large area glass substrate by a low-temperature hydrothermal growth process. Structural morphological investigations were carried out using field emission scanning electron microscopy, high resolution transmission electron microscopy, and X-ray diffraction. To check the sensing application of the CuO nanopetals, it was functionalized for selectivity of Ag+. A polymeric membrane with Ag+-selective ionophore was coated on the surface of the CuO nanopetals. CuO nanopetals reveal excellent electrochemical sensing behavior in aqueous solution to selectively detect Ag+. The CuO based sensor exhibits a linear electrochemical response within the concentration range of 1 mu M to 100 mM. The functionalized CuO nanopetal based sensor show stable, fast response and high sensitivity for [Ag+]. This work demonstrates a simple technique for sensitive detection of Ag+ and other biochemical species.

  • 2.
    Amin, Gul
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Asif, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    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.
    CuO Nanopetals Based Electrochemical Sensor for Selective Ag+ MeasurementsManuscript (preprint) (Other academic)
    Abstract [en]

    The electrochemical sensing activity of cupric oxide (CuO) nanopetals was investigated for the detection of silver (I) ions (Ag+. The CuO nanopetals were synthesized on a large area glass substrate by a low-temperature hydrothermal growth process. Structural morphological investigations were carried out using field emission scanning electron microscopy, high resolution transmission electron microscopy, and X-ray diffraction. To check the sensing application of the CuO nanopetals, it was functionalized for selectivity of Ag+. A polymeric membrane with Ag+-selective ionophore was coated on the surface of the CuO nanopetals. CuO nanopetals reveal excellent electrochemical sensing behavior in aqueous solution to selectively detect Ag+. The CuO based sensor exhibits a linear electrochemical response within the concentration range of 1 μM to 100 mM. The functionalized CuO nanopetal based sensor show stable, fast response and high sensitivity for [Ag+]. This work demonstrates a simple technique for sensitive detection of Ag+ and other biochemical species.

  • 3.
    Amin, Gul
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Asif, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    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.
    Influence of pH, Precursor Concentration, Growth Time, and Temperature on the Morphology of ZnO Nanostructures Grown by the Hydrothermal Method2011In: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, no 269692Article in journal (Refereed)
    Abstract [en]

    We investigated the influence of the pH value, precursor concentration (C), growth time and temperature on the morphology of zinc oxide (ZnO) nanostructures. The pH of the starting solution was varied from1.8 to 12.5. It was found that the final pH reaches an inherent value of 6.6 independently of the initial pH solution. Various ZnO structures of nanotetrapod-like, flower-like, and urchin-like morphology were obtained at alkaline pH (8 to 12.5) whereas for pH solution lower than 8 rod-like nanostructures occurred. Moreover, we observed the erosion of the nanorods for a pH value less than 4.6. By changing the concentrations the density and size were also varied. On going from a high (C > 400mM) to lower (C < 25mM) C, the resulted ZnO nanostructures change from a film to nanorods (NRs) and finally nanowires (NWs). It was also found that the length and diameter of ZnO NRs follow a linear relation with time up to 10 hours, above which no further increase was observed. Finally the effect of growth temperature was seen as an influence on the aspect ratio.

  • 4.
    Amin, Gul
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Hussain, I
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zaman, Saima
    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.
    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.
    Current-transport studies and trap extraction of hydrothermally grown ZnO nanotubes using gold Schottky diode2010In: PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, ISSN 1862-6300, Vol. 207, no 3, p. 748-752Article in journal (Refereed)
    Abstract [en]

    High-quality zinc oxide (ZnO) nanotubes (NTs) were grown by the hydrothermal technique on n-Si substrate. The room temperature (RT) current-transport mechanisms of Au Schottky diodes fabricated from ZnO NTs and nanorods (NRs) reference samples have been studied and compared. The tunneling mechanisms via deep-level states was found to be the main conduction process at low applied voltage but at the trap-filled limit voltage (V-TFL) all traps were filled and the space-charge-limited current conduction was the dominating current-transport mechanism. The deep-level trap energy and the trap concentration for; the NTs were obtained as similar to 0.27 eV and 2.1 x 10(16) cm(-3), respectively. The same parameters were also extracted for the ZnO NRs The deep-level states observed crossponds to zinc interstitials (Zn-i), which are responsible for the violet emission.

  • 5.
    Amin, Gul
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Sandberg, M. O.
    Acreo AB, Printed Electronics, P.O. Box 787, 60117 Norrköping, Sweden.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    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.
    Scale-up synthesis of ZnO nanorods for printing inexpensive ZnO/polymer white light-emitting diode2012In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 47, no 11, p. 4726-4731Article in journal (Refereed)
    Abstract [en]

    In this study, possibilities of scaling up the synthesis of zinc oxide (ZnO) nanorods (NRs) by the hydrothermal method have been explored. It was found that batches yielding several grams can easily be made using common and easily available materials. Further, a printable composition was fabricated by mixing the obtained ZnO NRs into a common solvent-based screen printable varnish. Scanning electron microscope, high-resolution transmission electron microscope, X-ray diffraction, UV–vis spectroscopy analysis of the scaled up batch indicated that the ZnO nanostructures were of NRs shape, well crystalline and having less defects. Using the ZnO NRs-based printable composition a device fabrication on a flexible substrate was demonstrated, producing a flexible light-emitting device being highly tolerant to bending.

  • 6.
    Amin, Gul
    et al.
    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.
    Zainelabdin, A
    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.
    ZnO nanorods-polymer hybrid white light emitting diode grown on a disposable paper substrate2011In: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 5, no 2, p. 71-73Article in journal (Refereed)
    Abstract [en]

    We demonstrate intrinsic white light emission from hybrid light emitting diodes fabricated using an inorganic-organic hybrid junction grown at 50 C on a paper substrate. Cyclotene was first spin coated on the entire substrate to act as a surface barrier layer for water and other nutrient solutions. The active area of the fabricated light emitting diode (LED) consists of zinc oxide nanorods (ZnO NRs) and a poly(9,9-dioctylfluorene) (PFO) conducting polymer layer. The fabricated LED shows clear rectifying behavior and a broad band electroluminescence (EL) peak covering the whole visible spectrum range from 420 nm to 780 nm. The color rendering index (CRI) was calculated to be 94 and the correlated color temperature (CCT) of the LED was 3660 K. The low process temperature and procedure in this work enables the use of paper substrate for the fabrication of low cost ZnO-polymer white LEDs for applications requiring flexible/disposable electronic devices.

  • 7.
    Bano, Nargis
    et al.
    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.
    Zainelabdin, A
    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.
    Hussain, I
    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.
    ZnO-organic hybrid white light emitting diodes grown on flexible plastic using low temperature aqueous chemical method2010In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, no 4, p. 043103-Article in journal (Refereed)
    Abstract [en]

    We demonstrate white light luminescence from ZnO-organic hybrid light emitting diodes grown at 90 degrees C on flexible plastic substrate by aqueous chemical growth. The configuration used for the ZnO-organic hybrid white light emitting diodes (WLEDs) consists of a layer of poly (9, 9-dioctylfluorene) (PFO) on poly (3, 4-ethylenedioxythiophene) poly (styrenesulfonate) coated plastic with top ZnO nanorods. Structural, electrical, and optical properties of these WLEDs were measured and analyzed. Room temperature electroluminescence spectrum reveals a broad emission band covering the range from 420 to 750 nm. In order to distinguish the white light components and contribution of the PFO layer we used a Gaussian function to simulate the experimental data. Color coordinates measurement of the WLED reveals that the emitted light has a white impression. The color rendering index and correlated color temperature of the WLED were calculated to be 68 and 5800 K, respectively.

  • 8.
    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.

  • 9.
    ul Hassan Alvi, Naveed
    et al.
    University of Politecn Madrid, Spain .
    Gomez, Victor J.
    University of Politecn Madrid, Spain .
    Soto Rodriguez, Paul E. D.
    University of Politecn Madrid, Spain .
    Kumar, Praveen
    University of Politecn Madrid, Spain .
    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.
    Noetzel, Richard
    University of Politecn Madrid, Spain .
    An InN/InGaN Quantum Dot Electrochemical Biosensor for Clinical Diagnosis2013In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, no 10, p. 13917-13927Article in journal (Refereed)
    Abstract [en]

    Low-dimensional InN/InGaN quantum dots (QDs) are demonstrated for realizing highly sensitive and efficient potentiometric biosensors owing to their unique electronic properties. The InN QDs are biochemically functionalized. The fabricated biosensor exhibits high sensitivity of 97 mV/decade with fast output response within two seconds for the detection of cholesterol in the logarithmic concentration range of 1 x 10(-6) M to 1 x 10(-3) M. The selectivity and reusability of the biosensor are excellent and it shows negligible response to common interferents such as uric acid and ascorbic acid. We also compare the biosensing properties of the InN QDs with those of an InN thin film having the same surface properties, i.e., high density of surface donor states, but different morphology and electronic properties. The sensitivity of the InN QDs-based biosensor is twice that of the InN thin film-based biosensor, the EMF is three times larger, and the response time is five times shorter. A bare InGaN layer does not produce a stable response. Hence, the superior biosensing properties of the InN QDs are governed by their unique surface properties together with the zero-dimensional electronic properties. Altogether, the InN QDs-based biosensor reveals great potential for clinical diagnosis applications.

  • 10.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Asif, Muhammad
    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.
    Zainelabdin, A.
    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.
    Al-Hilli, Safaa
    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.
    Different interfaces to crystalline ZnO nanorods and their applications2009In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 6, no 12, p. 2683-2694Article in journal (Refereed)
    Abstract [en]

    In this paper we will demonstrate the growth of crystalline ZnO nanorods on different substrates including some of crystalline as well as amorphous nature. The application of these ZnO nanorods to optoelectronics and to bioelectronics will be highlighted. We demonstrate the fabrication of n-ZnO nano-rods/p-type substrates and fabricated light emitting diodes (LEDs) based on these structures. Among the presented LEDs, a hybrid configuration based on the integration of p-type polymers on flexible plastic provides a potential for developing large area white LEDs. Moreover, ZnO nanorods based intracellular measurements using bare and functionalized ZnO surfaces were demonstrated to be a valuable non-destructive tool for obtaining intracellular measurements paving the way for a wealth of intracellular information.

  • 11.
    Willander, Magnus
    et al.
    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.
    Amin, Gul
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zainelabdin, A.
    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.
    Zinc oxide and copper oxide nanostructures: Fundamentals and applications2012In: Materials Research Society Symposium Proceedings: vol 1406, Warrendale, Pa.; Materials Research Society; 1999 , 2012, Vol. 1406, p. 3-10Conference paper (Refereed)
    Abstract [en]

    Copper oxide (CuO) and zinc oxide (ZnO) nanostructures complement each other since CuO is unintentional p-type and ZnO unintentional n-type. Using the low temperature chemical growth approach, the effect on morphology of varying the pH of the grown ZnO nanostructures and CuO micro structures is monitored. For both materials the variation of the pH was found to lead to a large variation on the morphology achieved. The grown ZnO NRs and CuO micro flowers material were used to fabricate devices. We demonstrate results from ZnO nanorods (NRs)/polymer p-n hybrid heterojunctions chemically grown on paper and using a process on paper for light emitting diodes (LEDs) applications as well as some large area light emitting diodes LEDs. The growth of CuO micro flowers indicated good quality material for sensing applications. The grown CuO micro flowers were employed as pH sensors. The results indicated a superior performance as expect due to the catalytic properties of this material. © 2012 Materials Research Society.

  • 12.
    Willander, Magnus
    et al.
    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.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Qadir, Muhammad Israr
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Saima
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, Ijaz
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Luminescence from Zinc Oxide Nanostructures and Polymers and their Hybrid Devices2010In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 3, no 4, p. 2643-2667Article, review/survey (Refereed)
    Abstract [en]

    Zinc oxide (ZnO) is a strong luminescent material, as are several polymers. These two materials have distinct drawbacks and advantages, and they can be combined to form nanostructures with many important applications, e. g., large-area white lighting. This paper discusses the origin of visible emission centers in ZnO nanorods grown with different approaches. White light emitting diodes (LEDs) were fabricated by combining n-ZnO nanorods and hollow nanotubes with different p-type materials to form heterojunctions. The p-type component of the hybrids includes p-SiC, p-GaN, and polymers. We conclude by analyzing the electroluminescence of the different light emitting diodes we fabricated. The observed optical, electrical, and electro-optical characteristics of these LEDs are discussed with an emphasis on the deep level centers that cause the emission.

  • 13.
    Willander, Magnus
    et al.
    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.
    Zaman, Siama
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zainelabdin, A
    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, I
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zinc oxide nanorods/polymer hybrid heterojunctions for white light emitting diodes2011In: JOURNAL OF PHYSICS D-APPLIED PHYSICS, ISSN 0022-3727, Vol. 44, no 22, p. 224017-Article in journal (Refereed)
    Abstract [en]

    Zinc oxide (ZnO) with its deep level defect emission covering the whole visible spectrum holds promise for the development of intrinsic white lighting sources with no need of using phosphors for light conversion. ZnO nanorods (NRs) grown on flexible plastic as substrate using a low temperature approach (down to 50 degrees C) were combined with different organic semiconductors to form hybrid junction. White electroluminescence (EL) was observed from these hybrid junctions. The configuration used for the hybrid white light emitting diodes (LEDs) consists of two-layers of polymers on the flexible plastic with ZnO NRs on the top. The inorganic/organic hybrid heterojunction has been fabricated by spin coating the p-type polymer poly (3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT : PSS) for hole injection with an ionization potential of 5.1 eV and poly(9, 9-dioctylfluorene) (PFO) is used as blue emitting material with a bandgap of 3.3 eV. ZnO NRs are grown on top of the organic layers. Two other configurations were also fabricated; these are using a single MEH PPV (red-emitting polymer) instead of the PFO and the third configuration was obtained from a blend of the PFO and the MEH PPV. The white LEDs were characterized by scanning electron microscope, x-ray diffraction (XRD), current-voltage (I-V) characteristics, room temperature photoluminescence (PL) and EL. The EL spectrum reveals a broad emission band covering the range from 420 to 800 nm, and the emissions causing this white luminescence were identified.

  • 14.
    Willander, Magnus
    et al.
    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.
    Zaman, Siama
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    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, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, I
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Alvi, Naveed ul Hassan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Intrinsic White Light Emission from Zinc Oxide Nanorods Heterojunctions on Large Area Substrates2011In: Proceedings of SPIE Volume 7940 / [ed] Ferechteh Hosseini Teherani, David C. Look, David J. Rogers, Bellingham, Washington, USA: SPIE - International Society for Optical Engineering, 2011Conference paper (Other academic)
    Abstract [en]

    Zinc oxide (ZnO) and especially in the nanostructure form is currently being intensively investigated world wide for the possibility of developing different new photonic devices. We will here present our recent findings on the controlled low temperature chemical growth of ZnO nanorods (NRs) on different large area substrates. Many different heterojunctions of ZnO NRs and p-substrates including those of crystalline e. g. p-GaN, p-SiC or amorphous nature e. g. p-polymer coated plastic and p-polymer coated paper will be shown. Moreover, the effect of the p-electrode of these heterojunctions on tuning the emitted wavelength and changing the light quality will be discussed. An example using ZnO NR/p-GaN will be shown and the electrical and electro-optical characteristics will be analyzed. For these heterojunctions the effect of post growth annealing and its effect on the electroluminescence (EL) spectrum will be shown. Finally, intrinsic white light emitting diodes based on ZnO NRs on foldable and disposable amorphous substrates (plastic and paper) will also be presented.

  • 15.
    Zainelabdin, A.
    et al.
    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.
    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.
    Deposition of Well-Aligned ZnO Nanorods at 50 degrees C on Metal, Semiconducting Polymer, and Copper Oxides Substrates and Their Structural and Optical Properties2010In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, no 7, p. 3250-3256Article in journal (Refereed)
    Abstract [en]

    A two-step chemical bath deposition was utilized to synthesize ZnO nanorod arrays (ZNRAs) on metals, poly(3,4-ethylenedioxythiophene)/poly(strenesulfonate) (PEDOT/PSS) coated flexible plastic foils, and copper oxides coated glass substrates. The whole synthesis procedure was carried out at a low temperature of 50 degrees C, without any other substrate treatments. The low growth temperature showed improved influence on both the ZNRAs structural and optical properties. Scanning electron microscopy (SEM) images revealed well-aligned ZNRAs with large aspect ratios, and X-ray diffraction (X RI)) analysis indicated that single crystalline ZNRAs were achieved with high c-axial orientation tendency. Room temperature photoluminescence (PL) measurements demonstrated excellent optical properties of the as-grown ZNRAs with very low defect concentration contrary to what was believed to be achieved when lowering the growth temperature. The impact of the low deposition temperature on the ZNRAs structure is discussed in connection to the thermodynamics constraints, while the temperature effect on the defects formation and density in the as-deposited ZNRAs is elaborated and compared with recent theoretical calculations that appeared in the literature.

  • 16.
    Zainelabdin, A
    et al.
    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.
    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.
    Stable White Light Electroluminescence from Highly Flexible Polymer/ZnO Nanorods Hybrid Heterojunction Grown at 50 degrees C2010In: Nanoscale research letters, ISSN 1556-276X, Vol. 5, no 9, p. 1442-1448Article in journal (Refereed)
    Abstract [en]

    Stable intrinsic white light-emitting diodes were fabricated from c-axially oriented ZnO nanorods (NRs) grown at 50 degrees C via the chemical bath deposition on top of a multi-layered poly(9,9-dioctylfluorene-co-N-(4-butylpheneylamine)diphenylamine)/poly(9,9dioctyl-fluorene) deposited on PEDOT:PSS on highly flexible plastic substrate. The low growth temperature enables the use of a variety of flexible plastic substrates. The fabricated flexible white light-emitting diode (FWLED) demonstrated good electrical properties and a single broad white emission peak extending from 420 nm and up to 800 nm combining the blue light emission of the polyflourene (PFO) polymer layer with the deep level emission (DLEs) of ZnO NRs. The influence of the temperature variations on the FWLED white emissions characteristics was studied and the devices exhibited high operation stability. Our results are promising for the development of white lighting sources using existing lighting glass bulbs, tubes, and armature technologies.

  • 17.
    Zainelabdin, A
    et al.
    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.
    Amin, Gul
    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.
    Optical and current transport properties of CuO/ZnO nanocoral p-n heterostructure hydrothermally synthesized at low temperature2012In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 108, no 4, p. 921-928Article in journal (Refereed)
    Abstract [en]

    We demonstrate the synthesis and investigate the electrical and optical characteristics of nanocorals (NCs) composed of CuO/ZnO grown at low temperature through the hydrothermal approach. High-density CuO nanostructures (NSs) were selectively grown on ZnO nanorods (NRs). The synthesized NCs were used to fabricate p-n heterojunctions that were investigated by the current density-voltage (J-V) and the capacitance-voltage (C-V) techniques. It was found that the NC heterojunctions exhibit a well-defined diode behavior with a threshold voltage of about 1.52 V and relatively high rectification factor of similar to 760. The detailed forward J-V characteristics revealed that the current transport is controlled by an ohmic behavior for V andlt;= 0.15 V, whereas at moderate voltages 1.46 andlt;= V andlt; 1.5 the current follows a J alpha exp(beta V) relationship. At higher voltages (andgt;= 1.5 V) the current follows the relation J alpha V-2, indicating that the space-charge-limited current mechanism is the dominant current transport. The C-V measurement indicated that the NC diode has an abrupt junction. The grown CuO/ZnO NCs exhibited a broad light absorption range that is covering the UV and the entire visible parts of the spectrum.

  • 18.
    Zainelabdin, Ahmed
    et al.
    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, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    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.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    CuO/ZnO Nanocorals synthesis via hydrothermal technique: growth mechanism and their application as Humidity Sensor2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 23, p. 11583-11590Article in journal (Refereed)
    Abstract [en]

    We demonstrate hydrothermal synthesis of coral-like CuO nanostructures by selective growth on ZnO nanorods (NR) at low temperatures. During the hydrothermal processing the resultant hydroxylated and eroded surface of ZnO NR becomes favorable for the CuO nanostructures growth via oriented attachments. Heterojunction p-n diodes fabricated from the CuO/ZnO nanocorals (NC) reveal stable and high rectification diode properties with a turn-on voltage ~1.52 V and negligible reverse current. The humidity sensing characteristics of the CuO/ZnO NC diodes exhibit a remarkable linear (in a semilogarithmic scale) decrease in the DC resistance by more than three orders when the relative humidity is changed from 30 – 90 %. The NC humidity sensor is also found to reveal the highest sensitivity factor ~6045 among available data for the constituent material’s and a response and recovery time of 6 s and 7 s, respectively.

  • 19.
    Zainelabdin, Ahmed
    et al.
    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.
    Hussain, S.
    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.
    Synthesis and Characterization of CuO/ZnO Composite Nanostructures: Precursor’s Effects, and their Optical Properties2012Manuscript (preprint) (Other academic)
    Abstract [en]

    A two steps hydrothermal method was developed to synthesize CuO/ZnO composite nanostructures (NSs) on glass substrate. The CuO NSs were selectively assembled on the lateral surface of ZnO nanorods (NRs) upon short growth duration. While the CuO NSs were entirely covered the surface of ZnO NRs at extended growth durations. The growth kinetics of CuO NSs is strongly dependent on the nature and the pH value of the precursor solution. When a single precursor solution of copper nitrate was applied in the synthesis process, a coral-like CuO/ZnO NSs were obtained. However, by adding a pH controlling agent to the precursor solution significant increase in the size of the grown CuO NSs was observed. The results revealed that the grown CuO NSs were robustly adhered to ZnO NRs, however, no explicit epitaxial relationship was found. The ZnO NRs band to band and defects emissions ratio was decreased compared to that of pure ZnO NRs, suggesting that oxygen vacancies are the probable growth sites of CuO NSs. The CuO/ZnO composite NSs exhibited a broad light absorption covering the whole visible range compared to the constituent materials. The low growth temperatures along with the optical properties of CuO/ZnO suggest these composite NSs may carry great potentials in light harvesting, sensing and emitting applications.

  • 20.
    Zaman, Saima
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Synthesis of ZnO, CuO and their Composite Nanostructures for Optoelectronics, Sensing and Catalytic Applications2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Research on nanomaterials has become increasingly popular because of their unique physical, chemical, optical and catalytic properties compared to their bulk counterparts. Therefore, many efforts have been made to synthesize multidimensional nanostructures for new and efficient nanodevices. Among those materials, zinc oxide (ZnO), has gained substantial attention owing to many outstanding properties. ZnO besides its wide bandgap of 3.34 eV exhibits a relatively large exciton binding energy (60 meV) at room temperature which is attractive for optoelectronic applications. Likewise, cupric oxide (CuO), having a narrow band gap of 1.2 eV and a variety of chemo-physical properties that are attractive in many fields. Moreover, composite nanostructures of these two oxides (CuO/ZnO) may pave the way for various new applications.

    This thesis can be divided into three parts concerning the synthesis, characterization and applications of ZnO, CuO and their composite nanostructures.

    In the first part the synthesis, characterization and the fabrication of ZnO nanorods based hybrid light emitting diodes (LEDs) are discussed. The low temperature chemical growth method was used to synthesize ZnO nanorods on different substrates, specifically on flexible non-crystalline substrates. Hybrid LEDs based on ZnO nanorods combined with p-type polymers were fabricated at low temperature to examine the advantage of both materials. A single and blended light emissive polymers layer was studied for controlling the quality of the emitted white light.

    The second part deals with the synthesis of CuO nanostructures (NSs) which were then used to fabricate pH sensors and exploit these NSs as a catalyst for degradation of organic dyes. The fabricated pH sensor exhibited a linear response and good potential stability. Furthermore, the catalytic properties of petals and flowers like CuO NSs in the degradation of organic dyes were studied. The results showed that the catalytic reactivity of the CuO is strongly depending on its shape.

    In the third part, an attempt to combine the advantages of both ZnO and CuO NSs was performed by developing a two-step chemical growth method to synthesize the composite NSs. The synthesized CuO/ZnO composite NSs revealed an extended light absorption and enhanced defect related visible emission.

    List of papers
    1. Deposition of Well-Aligned ZnO Nanorods at 50 degrees C on Metal, Semiconducting Polymer, and Copper Oxides Substrates and Their Structural and Optical Properties
    Open this publication in new window or tab >>Deposition of Well-Aligned ZnO Nanorods at 50 degrees C on Metal, Semiconducting Polymer, and Copper Oxides Substrates and Their Structural and Optical Properties
    Show others...
    2010 (English)In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, no 7, p. 3250-3256Article in journal (Refereed) Published
    Abstract [en]

    A two-step chemical bath deposition was utilized to synthesize ZnO nanorod arrays (ZNRAs) on metals, poly(3,4-ethylenedioxythiophene)/poly(strenesulfonate) (PEDOT/PSS) coated flexible plastic foils, and copper oxides coated glass substrates. The whole synthesis procedure was carried out at a low temperature of 50 degrees C, without any other substrate treatments. The low growth temperature showed improved influence on both the ZNRAs structural and optical properties. Scanning electron microscopy (SEM) images revealed well-aligned ZNRAs with large aspect ratios, and X-ray diffraction (X RI)) analysis indicated that single crystalline ZNRAs were achieved with high c-axial orientation tendency. Room temperature photoluminescence (PL) measurements demonstrated excellent optical properties of the as-grown ZNRAs with very low defect concentration contrary to what was believed to be achieved when lowering the growth temperature. The impact of the low deposition temperature on the ZNRAs structure is discussed in connection to the thermodynamics constraints, while the temperature effect on the defects formation and density in the as-deposited ZNRAs is elaborated and compared with recent theoretical calculations that appeared in the literature.

    Place, publisher, year, edition, pages
    The American Chemical Society, 2010
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-58270 (URN)10.1021/cg100390x (DOI)000279422700059 ()
    Available from: 2010-08-10 Created: 2010-08-09 Last updated: 2017-12-12
    2. ZnO nanorods-polymer hybrid white light emitting diode grown on a disposable paper substrate
    Open this publication in new window or tab >>ZnO nanorods-polymer hybrid white light emitting diode grown on a disposable paper substrate
    Show others...
    2011 (English)In: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 5, no 2, p. 71-73Article in journal (Refereed) Published
    Abstract [en]

    We demonstrate intrinsic white light emission from hybrid light emitting diodes fabricated using an inorganic-organic hybrid junction grown at 50 C on a paper substrate. Cyclotene was first spin coated on the entire substrate to act as a surface barrier layer for water and other nutrient solutions. The active area of the fabricated light emitting diode (LED) consists of zinc oxide nanorods (ZnO NRs) and a poly(9,9-dioctylfluorene) (PFO) conducting polymer layer. The fabricated LED shows clear rectifying behavior and a broad band electroluminescence (EL) peak covering the whole visible spectrum range from 420 nm to 780 nm. The color rendering index (CRI) was calculated to be 94 and the correlated color temperature (CCT) of the LED was 3660 K. The low process temperature and procedure in this work enables the use of paper substrate for the fabrication of low cost ZnO-polymer white LEDs for applications requiring flexible/disposable electronic devices.

    Place, publisher, year, edition, pages
    John Wiley and Sons, Ltd, 2011
    Keywords
    ZnO, PFO, LED, hybrid materials
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-67009 (URN)10.1002/pssr.201004446 (DOI)000288178300009 ()
    Available from: 2011-03-25 Created: 2011-03-25 Last updated: 2017-12-11Bibliographically approved
    3. Influence of the polymer concentration on the electroluminescence of ZnO nanorod/polymer hybrid light emitting diodes
    Open this publication in new window or tab >>Influence of the polymer concentration on the electroluminescence of ZnO nanorod/polymer hybrid light emitting diodes
    Show others...
    2012 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 112, no 6, p. 064324-Article in journal (Refereed) Published
    Abstract [en]

    The effects of the polymer concentration on the performance of hybrid light emitting diodes (LEDs) based on zinc oxide nanorods (ZnO NRs) and poly(9,9-dioctylfluorene) (PFO) was investigated. Various characterization techniques were applied to study the performance of the PFO/ZnO NR hybrid LEDs fabricated with various PFO concentrations. The fabricated hybrid LEDs demonstrated stable rectifying diode behavior, and it was observed that the turn-on voltage of the LEDs is concentration dependent. The measured room temperature electroluminescence (EL) showed that the PFO concentration plays a critical role in the emission spectra of the hybrid LEDs. At lower PFO concentrations of 2-6 mg/ml, the EL spectra are dominated by blue emission. However, by increasing the concentration to more than 8 mg/ml, the blue emission was completely suppressed while the green emission was dominant. This EL behavior was explained by a double trap system of excitons that were trapped in the β-phase and/or in the fluorenone defects in the PFO side. The effects of current injection on the hybrid LEDs and on the EL emission were also investigated. Under a high injection current, a new blue peak was observed in the EL spectrum, which was correlated to the creation of a new chemical species on the PFO chain. The green emission peak was also enhanced with increasing injection current because of the fluorenone defects. These results indicate that the emission spectra of the hybrid LEDs can be tuned by using different polymer concentrations and by varying the current injected into the device.

    Place, publisher, year, edition, pages
    American Institute of Physics (AIP), 2012
    Keywords
    Hybrid light emitting diodes, ZnO nanorods, PFO, electroluminescence
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-81426 (URN)10.1063/1.4754542 (DOI)000309423200142 ()
    Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2017-12-07Bibliographically approved
    4. Effect of the polymer emission on the electroluminescence characteristics of n-ZnO nanorods/p-polymer hybrid light emitting diode
    Open this publication in new window or tab >>Effect of the polymer emission on the electroluminescence characteristics of n-ZnO nanorods/p-polymer hybrid light emitting diode
    Show others...
    2011 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 104, no 4, p. 1203-1209Article in journal (Refereed) Published
    Abstract [en]

    Hybrid light emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods and polymers (single and blended) were fabricated and characterized. The ZnO nanorods were grown by the chemical bath deposition method at 50A degrees C. Three different LEDs, with blue emitting, orange-red emitting or their blended polymer together with ZnO nanorods, were fabricated and studied. The current-voltage characteristics show good diode behavior with an ideality factor in the range of 2.1 to 2.27 for all three devices. The electroluminescence spectrum (EL) of the blended device has an emission range from 450 nm to 750 nm, due to the intermixing of the blue emission generated by poly(9,9-dioctylfluorene) denoted as PFO with orange-red emission produced by poly(2-methoxy-5(20-ethyl-hexyloxy)-1,4-phenylenevinylene) 1,4-phenylenevinylene) symbolized as MEH PPV combined with the deep-band emission (DBE) of the ZnO nanorods, i.e. it covers the whole visible region and is manifested as white light. The CIE color coordinates showed bluish, orange-red and white emission from the PFO, MEH PPV and blended LEDs with ZnO nanorods, respectively. These results indicate that the choice of the polymer with proper concentration is critical to the emitted color in ZnO nanorods/p-organic polymer LEDs and careful design should be considered to obtain intrinsic white light sources.

    Place, publisher, year, edition, pages
    Springer Verlag (Germany), 2011
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-70328 (URN)10.1007/s00339-011-6411-3 (DOI)000293972100029 ()
    Available from: 2011-09-02 Created: 2011-09-02 Last updated: 2017-12-08
    5. CuO nanoflowers as an electrochemical pH sensor and the effect of pH on the growth
    Open this publication in new window or tab >>CuO nanoflowers as an electrochemical pH sensor and the effect of pH on the growth
    Show others...
    2011 (English)In: JOURNAL OF ELECTROANALYTICAL CHEMISTRY, ISSN 1572-6657, Vol. 662, no 2, p. 421-425Article in journal (Refereed) Published
    Abstract [en]

    Well-crystallized flower-shaped cupric oxide (CuO) nanostructures composed of thin leaves have been synthesized by simple low-temperature chemical bath method and used to fabricate pH sensor. We examined the effect of the pH on the growth of the CuO nanostructures, by changing the pH of the precursor solutions different morphologies of the CuO nanostructures were obtained. CuO nanoflowers have recently become important as a material that provides an effective surface for electrochemical activities with enhanced sensing characteristics. The proposed sensor exhibited a linear electrochemical response within a wide pH range of (2-11). The experimental results (time response, electrochemical activity, reproducibility, absorption spectra, and XRD) indicate that the CuO nanoflowers can be used in pH sensor applications with enhanced properties.

    Place, publisher, year, edition, pages
    Elsevier, 2011
    Keywords
    CuO nanoflower; Morphological effect; Electrochemical; pH sensor; Repeatability
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-73334 (URN)10.1016/j.jelechem.2011.09.015 (DOI)000297881200020 ()
    Available from: 2012-01-03 Created: 2012-01-02 Last updated: 2014-01-15
    6. Efficient catalytic effect of CuO nanostructures on the degradation of organic dyes
    Open this publication in new window or tab >>Efficient catalytic effect of CuO nanostructures on the degradation of organic dyes
    Show others...
    2012 (English)In: Journal of Physics and Chemistry of Solids, ISSN 0022-3697, E-ISSN 1879-2553, Vol. 73, no 11, p. 1320-1325Article in journal (Refereed) Published
    Abstract [en]

    An efficient catalytic effect of petals and flowers like CuO nanostructures (NSs) on the degradation of two organic dyes, methylene blue (MB) and rhodamine B (RB) were investigated. The highest degradation of 95% in CuO petals and 72% in flowers for MB is observed in 24 h. For RB, the degradation was 85% and 80% in petals and flowers, respectively for 5 h. It was observed that CuO petals appeared to be more active than flowers for degradation of both dyes associated to high specific surface area. The petals and flower like CuO NSs were synthesized using the chemical bath method at 90 °C. The grown CuO NSs were characterized using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD).

    Keywords
    A. Nanostructures; B. Chemical synthesis; C. X-ray diffraction; D. Crystal structure
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-81427 (URN)10.1016/j.jpcs.2012.07.005 (DOI)000308778900012 ()
    Note

    funding agencies|Advanced Functional Materials (AFT) grant at Linkoping University, Sweden||MUST University AJK, Pakistan||

    Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2017-12-07Bibliographically approved
    7. Synthesis and Characterization of CuO/ZnO Composite Nanostructures: Precursor’s Effects, and their Optical Properties
    Open this publication in new window or tab >>Synthesis and Characterization of CuO/ZnO Composite Nanostructures: Precursor’s Effects, and their Optical Properties
    Show others...
    2012 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    A two steps hydrothermal method was developed to synthesize CuO/ZnO composite nanostructures (NSs) on glass substrate. The CuO NSs were selectively assembled on the lateral surface of ZnO nanorods (NRs) upon short growth duration. While the CuO NSs were entirely covered the surface of ZnO NRs at extended growth durations. The growth kinetics of CuO NSs is strongly dependent on the nature and the pH value of the precursor solution. When a single precursor solution of copper nitrate was applied in the synthesis process, a coral-like CuO/ZnO NSs were obtained. However, by adding a pH controlling agent to the precursor solution significant increase in the size of the grown CuO NSs was observed. The results revealed that the grown CuO NSs were robustly adhered to ZnO NRs, however, no explicit epitaxial relationship was found. The ZnO NRs band to band and defects emissions ratio was decreased compared to that of pure ZnO NRs, suggesting that oxygen vacancies are the probable growth sites of CuO NSs. The CuO/ZnO composite NSs exhibited a broad light absorption covering the whole visible range compared to the constituent materials. The low growth temperatures along with the optical properties of CuO/ZnO suggest these composite NSs may carry great potentials in light harvesting, sensing and emitting applications.

    Keywords
    Hydrothermal, ZnO nanorods, CuO nanostructures, deep level defects, composite
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-81428 (URN)
    Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2014-01-15Bibliographically approved
  • 21.
    Zaman, Siama
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Asif, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zainelabdin, A.
    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.
    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.
    CuO nanoflowers as an electrochemical pH sensor and the effect of pH on the growth2011In: JOURNAL OF ELECTROANALYTICAL CHEMISTRY, ISSN 1572-6657, Vol. 662, no 2, p. 421-425Article in journal (Refereed)
    Abstract [en]

    Well-crystallized flower-shaped cupric oxide (CuO) nanostructures composed of thin leaves have been synthesized by simple low-temperature chemical bath method and used to fabricate pH sensor. We examined the effect of the pH on the growth of the CuO nanostructures, by changing the pH of the precursor solutions different morphologies of the CuO nanostructures were obtained. CuO nanoflowers have recently become important as a material that provides an effective surface for electrochemical activities with enhanced sensing characteristics. The proposed sensor exhibited a linear electrochemical response within a wide pH range of (2-11). The experimental results (time response, electrochemical activity, reproducibility, absorption spectra, and XRD) indicate that the CuO nanoflowers can be used in pH sensor applications with enhanced properties.

  • 22.
    Zaman, Siama
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zainelabdin, A
    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.
    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.
    Effect of the polymer emission on the electroluminescence characteristics of n-ZnO nanorods/p-polymer hybrid light emitting diode2011In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 104, no 4, p. 1203-1209Article in journal (Refereed)
    Abstract [en]

    Hybrid light emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods and polymers (single and blended) were fabricated and characterized. The ZnO nanorods were grown by the chemical bath deposition method at 50A degrees C. Three different LEDs, with blue emitting, orange-red emitting or their blended polymer together with ZnO nanorods, were fabricated and studied. The current-voltage characteristics show good diode behavior with an ideality factor in the range of 2.1 to 2.27 for all three devices. The electroluminescence spectrum (EL) of the blended device has an emission range from 450 nm to 750 nm, due to the intermixing of the blue emission generated by poly(9,9-dioctylfluorene) denoted as PFO with orange-red emission produced by poly(2-methoxy-5(20-ethyl-hexyloxy)-1,4-phenylenevinylene) 1,4-phenylenevinylene) symbolized as MEH PPV combined with the deep-band emission (DBE) of the ZnO nanorods, i.e. it covers the whole visible region and is manifested as white light. The CIE color coordinates showed bluish, orange-red and white emission from the PFO, MEH PPV and blended LEDs with ZnO nanorods, respectively. These results indicate that the choice of the polymer with proper concentration is critical to the emitted color in ZnO nanorods/p-organic polymer LEDs and careful design should be considered to obtain intrinsic white light sources.

  • 23.
    Zaman, Siama
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zainelabdin, A
    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.
    Low-Temperature Chemical Growth of ZnO Nanorods with Enhanced UV Emission on Plastic Substrates2010In: JOURNAL OF NANOELECTRONICS AND OPTOELECTRONICS, ISSN 1555-130X, Vol. 5, no 1, p. 50-54Article in journal (Refereed)
    Abstract [en]

    In this paper we report ZnO nanorods (NRs) grown by a two step chemical bath deposition method at temperature down to 50 degrees C. The structural and optical properties of the as deposited ZnO NRs grown at 50 degrees C, 75 degrees C, and 95 degrees C, were all investigated and compared using X-ray diffraction and photoluminescence. X-ray diffraction verified that all grown ZnO NRs have a preferential growth orientation along the c-axis and that all samples show the same peaks with the same intensity indicating the same structural quality despite the different growth temperatures. By comparing the PL of the different samples grown at different temperatures, surprisingly the sample grown at the lowest temperature (50 degrees C) exhibit an enhancement in the near band emission intensities by more than three orders of magnitude and a suppressed deep level emission by the same amount. This is explained by the fact that the lower growth temperature did not provide enough energy for native point defects to nucleate.

  • 24.
    Zaman, Siama
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    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.
    Efficient catalytic effect of CuO nanostructures on the degradation of organic dyes2012In: Journal of Physics and Chemistry of Solids, ISSN 0022-3697, E-ISSN 1879-2553, Vol. 73, no 11, p. 1320-1325Article in journal (Refereed)
    Abstract [en]

    An efficient catalytic effect of petals and flowers like CuO nanostructures (NSs) on the degradation of two organic dyes, methylene blue (MB) and rhodamine B (RB) were investigated. The highest degradation of 95% in CuO petals and 72% in flowers for MB is observed in 24 h. For RB, the degradation was 85% and 80% in petals and flowers, respectively for 5 h. It was observed that CuO petals appeared to be more active than flowers for degradation of both dyes associated to high specific surface area. The petals and flower like CuO NSs were synthesized using the chemical bath method at 90 °C. The grown CuO NSs were characterized using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD).

  • 25.
    Zaman, Siama
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    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.
    Influence of the polymer concentration on the electroluminescence of ZnO nanorod/polymer hybrid light emitting diodes2012In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 112, no 6, p. 064324-Article in journal (Refereed)
    Abstract [en]

    The effects of the polymer concentration on the performance of hybrid light emitting diodes (LEDs) based on zinc oxide nanorods (ZnO NRs) and poly(9,9-dioctylfluorene) (PFO) was investigated. Various characterization techniques were applied to study the performance of the PFO/ZnO NR hybrid LEDs fabricated with various PFO concentrations. The fabricated hybrid LEDs demonstrated stable rectifying diode behavior, and it was observed that the turn-on voltage of the LEDs is concentration dependent. The measured room temperature electroluminescence (EL) showed that the PFO concentration plays a critical role in the emission spectra of the hybrid LEDs. At lower PFO concentrations of 2-6 mg/ml, the EL spectra are dominated by blue emission. However, by increasing the concentration to more than 8 mg/ml, the blue emission was completely suppressed while the green emission was dominant. This EL behavior was explained by a double trap system of excitons that were trapped in the β-phase and/or in the fluorenone defects in the PFO side. The effects of current injection on the hybrid LEDs and on the EL emission were also investigated. Under a high injection current, a new blue peak was observed in the EL spectrum, which was correlated to the creation of a new chemical species on the PFO chain. The green emission peak was also enhanced with increasing injection current because of the fluorenone defects. These results indicate that the emission spectra of the hybrid LEDs can be tuned by using different polymer concentrations and by varying the current injected into the device.

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