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Zaman, Saima
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Publications (10 of 25) Show all publications
ul Hassan Alvi, N., Gomez, V. J., Soto Rodriguez, P. E. D., Kumar, P., Zaman, S., Willander, M. & Noetzel, R. (2013). An InN/InGaN Quantum Dot Electrochemical Biosensor for Clinical Diagnosis. Sensors, 13(10), 13917-13927
Open this publication in new window or tab >>An InN/InGaN Quantum Dot Electrochemical Biosensor for Clinical Diagnosis
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2013 (English)In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, no 10, p. 13917-13927Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
MDPI, 2013
Keywords
functionalized InN quantum dots; highly sensitive and efficient biosensors; potentiometric; clinical diagnosis
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-103311 (URN)10.3390/s131013917 (DOI)000328625300066 ()
Available from: 2014-01-16 Created: 2014-01-16 Last updated: 2017-12-06
Amin, G., Asif, M., Elsharif Zainelabdin, A., Zaman, S., Nur, O. & Willander, M. (2012). CuO Nanopetals Based Electrochemical Sensor for Selective Ag+ Measurements. SENSOR LETTERS, 10(3-4), 754-759
Open this publication in new window or tab >>CuO Nanopetals Based Electrochemical Sensor for Selective Ag+ Measurements
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2012 (English)In: SENSOR LETTERS, ISSN 1546-198X, Vol. 10, no 3-4, p. 754-759Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
American Scientific Publishers, 2012
Keywords
CuO, Nanopetals, Hydrothermal Method, Ag+-Selective Membrane, Electrochemical Sensor
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-85097 (URN)10.1166/sl.2012.2336 (DOI)000309018700011 ()
Available from: 2012-11-02 Created: 2012-11-02 Last updated: 2018-02-27
Zainelabdin, A., Amin, G., Zaman, S., Nur, O., Lu, J., Hultman, L. & Willander, M. (2012). CuO/ZnO Nanocorals synthesis via hydrothermal technique: growth mechanism and their application as Humidity Sensor. Journal of Materials Chemistry, 22(23), 11583-11590
Open this publication in new window or tab >>CuO/ZnO Nanocorals synthesis via hydrothermal technique: growth mechanism and their application as Humidity Sensor
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2012 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 23, p. 11583-11590Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2012
Keywords
Zinc oxide nanorods, copper oxide nanostructures, nanocorals, relative humidity, sensitivity factor
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-76676 (URN)10.1039/c2jm16597j (DOI)000304351400026 ()
Note
funding agencies|Swedish government||Available from: 2012-04-16 Created: 2012-04-16 Last updated: 2017-12-07Bibliographically approved
Zaman, S., Zainelabdin, A., Amin, G., Nour, O. & Willander, M. (2012). Efficient catalytic effect of CuO nanostructures on the degradation of organic dyes. Journal of Physics and Chemistry of Solids, 73(11), 1320-1325
Open this publication in new window or tab >>Efficient catalytic effect of CuO nanostructures on the degradation of organic dyes
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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
Zaman, S., Zainelabdin, A., Amin, G., Nour, O. & Willander, M. (2012). Influence of the polymer concentration on the electroluminescence of ZnO nanorod/polymer hybrid light emitting diodes. Journal of Applied Physics, 112(6), 064324
Open this publication in new window or tab >>Influence of the polymer concentration on the electroluminescence of ZnO nanorod/polymer hybrid light emitting diodes
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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
Elsharif Zainelabdin, A., Nur, O., Amin, G., Zaman, S. & Willander, M. (2012). Metal Oxide Nanostructures and White Light Emission. Proceedings of SPIE, the International Society for Optical Engineering, 8263(82630N)
Open this publication in new window or tab >>Metal Oxide Nanostructures and White Light Emission
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2012 (English)In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 8263, no 82630NArticle in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
International Society for Optical Engineering; 1999, 2012
Keywords
nanostructures; zinc oxide; copper oxide
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-87980 (URN)10.1117/12.909342 (DOI)000303381200013 ()
Available from: 2013-01-28 Created: 2013-01-28 Last updated: 2017-12-06
Zainelabdin, A., Zaman, S., Amin, G., Nur, O. & Willander, M. (2012). Optical and current transport properties of CuO/ZnO nanocoral p-n heterostructure hydrothermally synthesized at low temperature. Applied Physics A: Materials Science & Processing, 108(4), 921-928
Open this publication in new window or tab >>Optical and current transport properties of CuO/ZnO nanocoral p-n heterostructure hydrothermally synthesized at low temperature
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2012 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 108, no 4, p. 921-928Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Springer Verlag (Germany), 2012
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-81220 (URN)10.1007/s00339-012-6995-2 (DOI)000307332800022 ()
Available from: 2012-09-10 Created: 2012-09-10 Last updated: 2017-12-07
Amin, G., Sandberg, M. O., Zainelabdin, A., Zaman, S., Nur, O. & Willander, M. (2012). Scale-up synthesis of ZnO nanorods for printing inexpensive ZnO/polymer white light-emitting diode. Journal of Materials Science, 47(11), 4726-4731
Open this publication in new window or tab >>Scale-up synthesis of ZnO nanorods for printing inexpensive ZnO/polymer white light-emitting diode
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2012 (English)In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 47, no 11, p. 4726-4731Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Springer, 2012
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-76674 (URN)10.1007/s10853-012-6342-1 (DOI)000302244500026 ()
Available from: 2012-04-16 Created: 2012-04-16 Last updated: 2017-12-07Bibliographically approved
Zainelabdin, A., Zaman, S., Hussain, S., Nour, O. & Willander, M. (2012). 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
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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
Zaman, S. (2012). Synthesis of ZnO, CuO and their Composite Nanostructures for Optoelectronics, Sensing and Catalytic Applications. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Synthesis of ZnO, CuO and their Composite Nanostructures for Optoelectronics, Sensing and Catalytic Applications
2012 (English)Doctoral 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.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2012. p. 59
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1467
Keywords
ZnO, CuO, Nanostructures, Low temperature growth, Light emitting diodes, pH sensors
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-81120 (URN)978-91-7519-818-7 (ISBN)
Public defence
2012-09-28, K3, Kåkenhus, Campus Norrköping, Linköping University, Norrköping, 10:15 (English)
Opponent
Supervisors
Available from: 2012-09-07 Created: 2012-09-07 Last updated: 2019-12-10Bibliographically approved
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