uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Topalian, Z
Alternative names
Publications (10 of 27) Show all publications
Ionescu, R., Cindemir, U., Welearegay, T. G., Calavia, R., Haddi, Z., Topalian, Z., . . . Llobet, E. (2017). Fabrication of ultra-pure gold nanoparticles capped with dodecanethiol for Schottky-diode chemical gas sensing devices. Sensors and actuators. B, Chemical, 239, 455-461
Open this publication in new window or tab >>Fabrication of ultra-pure gold nanoparticles capped with dodecanethiol for Schottky-diode chemical gas sensing devices
Show others...
2017 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 239, p. 455-461Article in journal (Refereed) Published
Abstract [en]

Ultra-pure monolayer-capped gold nanoparticles for chemical gas sensing devices were prepared by a novel two-step process: a physical vapour deposition technique was first employed to make dispersed ultra-pure size-controlled gold nanoparticles, and this step was followed by a coating process for functionalization of the gold nanoparticles with an organic ligand, specifically dodecanethiol. X-ray photoelectron spectroscopy proved that the nano-assemblies had high purity. Chemical sensing devices based on these nano-assemblies showed Schottky-diode behaviour. We believe this is the first observation of Schottky-diodes fabricated from nanomaterials based on metallic nanoparticles. Gas sensing experiments demonstrated that these devices were suitable for detecting volatile organic compounds.

National Category
Engineering and Technology Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-302548 (URN)10.1016/j.snb.2016.07.182 (DOI)000388951300056 ()
Funder
EU, FP7, Seventh Framework Programme, 267234
Available from: 2016-09-06 Created: 2016-09-06 Last updated: 2017-09-28Bibliographically approved
Lentka, L., Kotarski, M., Smulko, J., Cindemir, U., Topalian, Z., Granqvist, C.-G., . . . Ionescu, R. (2016). Fluctuation-enhanced sensing with organically functionalized gold nanoparticle gas sensors targeting biomedical applications. Talanta: The International Journal of Pure and Applied Analytical Chemistry, 160, 9-14
Open this publication in new window or tab >>Fluctuation-enhanced sensing with organically functionalized gold nanoparticle gas sensors targeting biomedical applications
Show others...
2016 (English)In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 160, p. 9-14Article in journal (Refereed) Published
Abstract [en]

Detection of volatile organic compounds is a useful approach to non-invasive diagnosis of diseases through breath analysis. Our experimental study presents a newly developed prototype gas sensor, based on organically-functionalized gold nanoparticles, and results on formaldehyde detection using fluctuation-enhanced gas sensing. Formaldehyde was easily detected via intense fluctuations of the gas sensor's resistance, while the cross-influence of ethanol vapor (a confounding factor in exhaled breath, related to alcohol consumption) was negligible.

Keywords
Organically-functionalized gold nanoparticles; Formaldehyde detection; Fluctuation enhanced sensing; Flicker noise
National Category
Chemical Engineering
Identifiers
urn:nbn:se:uu:diva-302550 (URN)10.1016/j.talanta.2016.06.063 (DOI)000383524400002 ()27591581 (PubMedID)
Funder
EU, European Research Council, 267234
Available from: 2016-09-06 Created: 2016-09-06 Last updated: 2017-11-21Bibliographically approved
Topalian, Z., Li, S.-Y., Niklasson, G. A., Granqvist, C. & Kish, L. B. (2015). Percolation noise at the metal-insulator transition of nanostructured VO2 films. In: Extended Abstracts: . Paper presented at Conference on Unsolved Problems of Noise (UPoN), Barcelona, Spanien, Juli 13-17.
Open this publication in new window or tab >>Percolation noise at the metal-insulator transition of nanostructured VO2 films
Show others...
2015 (English)In: Extended Abstracts, 2015Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-268305 (URN)
Conference
Conference on Unsolved Problems of Noise (UPoN), Barcelona, Spanien, Juli 13-17
Available from: 2015-12-03 Created: 2015-12-03 Last updated: 2018-08-30
Topalian, Z., Li, S.-Y., Niklasson, G. A., Granqvist, C. G. & Kish, L. B. (2015). Resistance noise at the metal-insulator transition in thermochromic VO2 films. Journal of Applied Physics, 117(2), 1-7, Article ID 025303.
Open this publication in new window or tab >>Resistance noise at the metal-insulator transition in thermochromic VO2 films
Show others...
2015 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, no 2, p. 1-7, article id 025303Article in journal (Refereed) Published
Abstract [en]

Thermochromic VO2 films were prepared by reactive DC magnetron sputtering onto heated sapphire substrates and were used to make 100-nm-thick samples that were 10 lm wide and 100 lm long. The resistance of these samples changed by a factor similar to 2000 in the 50<T-s<70 degrees C range of temperature T-s around the "critical" temperature T-c between a low-temperature semiconducting phase and a high-temperature metallic-like phase of VO2. Power density spectra S(f) were extracted for resistance noise around T-c and demonstrated unambiguous 1/f behavior. Data on S(10 Hz)/R-s(2) scaled as R-s(x), where R-s is sample resistance; the noise exponent x was -2.6 for T-s< T-c and +2.6 for T-s>T-c. These exponents can be reconciled with the Pennetta-Trefan-Reggiani theory [Pennetta et al., Phys. Rev. Lett. 85, 5238 (2000)] for lattice percolation with switching disorder ensuing from random defect generation and healing in steady state. Our work hence highlights the dynamic features of the percolating semiconducting and metallic-like regions around T-c in thermochromic VO2 films. (C) 2015 AIP Publishing LLC.

National Category
Other Physics Topics Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-245367 (URN)10.1063/1.4905739 (DOI)000348129300064 ()
Available from: 2015-02-26 Created: 2015-02-26 Last updated: 2017-12-04Bibliographically approved
Stefanov, B. I., Topalian, Z., Granqvist, C.-G. & Österlund, L. (2014). Acetaldehyde Adsorption and Condensation on Anatase TiO2: Influence of Acetaldehyde Dimerization. Journal of Molecular Catalysis A: Chemical, 381, 77-88
Open this publication in new window or tab >>Acetaldehyde Adsorption and Condensation on Anatase TiO2: Influence of Acetaldehyde Dimerization
2014 (English)In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 381, p. 77-88Article in journal (Refereed) Published
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-284408 (URN)
Available from: 2016-04-18 Created: 2016-04-18 Last updated: 2017-11-30
Stefanov, B. I., Topalian, Z., Granqvist, C.-G. & Österlund, L. (2014). Acetaldehyde adsorption and condensation on anatase TiO2: Influence of acetaldehyde dimerization. Journal of Molecular Catalysis A: Chemical, 381, 77-88
Open this publication in new window or tab >>Acetaldehyde adsorption and condensation on anatase TiO2: Influence of acetaldehyde dimerization
2014 (English)In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 381, p. 77-88Article in journal (Refereed) Published
Abstract [en]

Conversion of acetaldehyde to crotonaldehyde on anatase TiO2 films was studied by in situ Fourier transform infrared spectroscopy (FTIR) and by density functional theory (DFT) calculations. In situ FTIR showed that acetaldehyde adsorption is accompanied by the appearance of a hitherto non-assigned absorption band at 1643 cm−1, which is shown to be due to acetaldehyde dimers. The results were supported by DFT calculations. Vibrational frequencies calculated within a partially relaxed cluster model for molecular acetaldehyde and its dimer, and for the corresponding adsorbed species on the anatase (101) surface, were in good agreement with experimental results. A kinetic model was constructed based on the combined FTIR and DFT results, and was shown to explain the essential features of the acetaldehyde condensation reaction.

Place, publisher, year, edition, pages
Elsevier, 2014
Keywords
TiO2, acetaldehyde, Crotonaldehyde, Dimer, Adsorption, DFT, FTIR
National Category
Chemical Process Engineering Nano Technology Inorganic Chemistry Theoretical Chemistry
Research subject
Chemistry with specialization in Materials Chemistry; Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-209695 (URN)10.1016/j.molcata.2013.10.005 (DOI)000329384300011 ()
Projects
EU GRINDOOR
Funder
EU, FP7, Seventh Framework Programme, 267234Swedish Research Council, VR 2010-3514
Available from: 2013-10-26 Created: 2013-10-24 Last updated: 2017-12-06Bibliographically approved
Cindemir, U., Topalian, Z., Calavia, R., Llobet, E., Granqvist, C.-G. & Ionescu, R. (2014). Gold Nanoparticle Thin Film Sensors for Formaldehyde Detection. In: : . Paper presented at European Materials Research Soviety (E-MRS) Spring Meeting, Lille, France, 26-30 May (pp. 1).
Open this publication in new window or tab >>Gold Nanoparticle Thin Film Sensors for Formaldehyde Detection
Show others...
2014 (English)Conference paper, Published paper (Refereed)
Series
Abstracts European Materials Research Soviety (E-MRS) Spring Meeting ; B PI-34
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-237787 (URN)
Conference
European Materials Research Soviety (E-MRS) Spring Meeting, Lille, France, 26-30 May
Available from: 2014-12-05 Created: 2014-12-05 Last updated: 2014-12-05
Österlund, L. & Topalian, Z. (2014). Photocatalytic oxide films in the built environment. In: Assoc. Prof. Dr.Tatyana Ivanova, Prof. DSc Kostadinka Gesheva, Prof. DSc Hassan Chamatti, Assoc. Prof. Dr. Georgi Popkirov (Ed.), INERA Workshop: Transition Metal Oxide Thin Films-functional Layers in "Smart windows" and Water Splitting Devices: . Paper presented at INERA Workshop: Transition Metal Oxide Thin Films-functional Layers in "Smart windows" and Water Splitting Devices. Parallel session of the 18th International School on Condensed Matter Physics (pp. 012009). Institute of Physics (IOP)
Open this publication in new window or tab >>Photocatalytic oxide films in the built environment
2014 (English)In: INERA Workshop: Transition Metal Oxide Thin Films-functional Layers in "Smart windows" and Water Splitting Devices / [ed] Assoc. Prof. Dr.Tatyana Ivanova, Prof. DSc Kostadinka Gesheva, Prof. DSc Hassan Chamatti, Assoc. Prof. Dr. Georgi Popkirov, Institute of Physics (IOP), 2014, p. 012009-Conference paper, Published paper (Refereed)
Abstract [en]

The possibility to increase human comfort in buildings is a powerful driving force for the introduction of new technology. Among other things our sense of comfort depends on air quality, temperature, lighting level, and the possibility of having visual contact between indoors and outdoors. Indeed there is an intimate connection between energy, comfort, and health issues in the built environment, leading to a need for intelligent building materials and green architecture. Photocatalytic materials can be applied as coatings, filters, and be embedded in building materials to provide self-cleaning, antibacterial, air cleaning, deodorizing, and water cleaning functions utilizing either solar light or artificial illumination sources – either already present in buildings, or by purposefully designed luminaries. Huge improvements in indoor comfort can thus be made, and also alleviate negative health effects associated with buildings, such as the sick-house syndrome. At the same time huge cost savings can be made by reducing maintenance costs. Photocatalytic oxides can be chemical modified by changing their acid-base surface properties, which can be used to overcome deactivation problems commonly encountered for TiO2 in air cleaning applications [2, 3]. In addition, the wetting properties oxides can be tailored by surface chemical modifications and made e.g. oleophobic and water repellent [5]. Here we show results of surface acid modified TiO2 coatings on various substrates. In particular, we show that advanced surface treatment of photocatalytic cement yields surfaces with beneficial self-cleaning properties by means of photo-fixation of surface sulfate groups. We propose that such approaches are feasible for a number of applications in the built environment, including windows, tiles, sheet metals, plastics, etc.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2014
Series
Journal of Physics: Conference Series, ISSN 1742-6588 ; 559
National Category
Engineering and Technology Materials Engineering Chemical Engineering Nano Technology
Research subject
Chemistry with specialization in Materials Chemistry; Engineering Science with specialization in Nanotechnology and Functional Materials; Engineering Science with specialization in Solid State Physics; Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-237533 (URN)10.1088/1742-6596/559/1/012009 (DOI)000346420600009 ()
Conference
INERA Workshop: Transition Metal Oxide Thin Films-functional Layers in "Smart windows" and Water Splitting Devices. Parallel session of the 18th International School on Condensed Matter Physics
Projects
Built environment, photocatalysis, wetting, surfaces, oxides
Funder
EU, FP7, Seventh Framework Programme, NMP4-SL-2013-608950
Available from: 2014-12-03 Created: 2014-12-03 Last updated: 2015-01-26Bibliographically approved
Österlund, L. & Topalian, Z. (2014). Photocatalytic oxide films in the built environment. Journal of Physics, Conference Series, 559(1), 012009
Open this publication in new window or tab >>Photocatalytic oxide films in the built environment
2014 (English)In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 559, no 1, p. 012009-Article in journal (Refereed) Published
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-286508 (URN)
Available from: 2016-04-20 Created: 2016-04-20 Last updated: 2017-11-30
Cindemir, U., Topalian, Z., Österlund, L., Granqvist, C.-G. & Gunnar, N. (2014). Porous Nickel Oxide Film Sensor for Formaldehyde. In: INERA Workshop: Transition Metal Oxides as Functional Layers in Smart windows and Water Splitting Devices / Parallel session of the 18th International School on Condensed Matter Physics: . Paper presented at INERA Workshop on Transition Metal Oxides as Functional Layers in Smart windows and Water Splitting Devices / Parallel session of the 18th International School on Condensed Matter Physics, sep 4-6, 2014, Varna, Bulgaria (pp. UNSP 012012).
Open this publication in new window or tab >>Porous Nickel Oxide Film Sensor for Formaldehyde
Show others...
2014 (English)In: INERA Workshop: Transition Metal Oxides as Functional Layers in Smart windows and Water Splitting Devices / Parallel session of the 18th International School on Condensed Matter Physics, 2014, p. UNSP 012012-Conference paper, Published paper (Refereed)
Abstract [en]

Formaldehyde is a volatile organic compound and a harmful indoor pollutant contributing to the "sick building syndrome". We used advanced gas deposition to fabricate highly porous nickel oxide (NiO) thin films for formaldehyde sensing. The films were deposited on Al2O3 substrates with prefabricated comb-structured electrodes and a resistive heater at the opposite face. The morphology and structure of the films were investigated with scanning electron microscopy and X-ray diffraction. Porosity was determined by nitrogen adsorption isotherms with the Brunauer-Emmett-Teller method. Gas sensing measurements were performed to demonstrate the resistive response of the sensors with respect to different concentrations of formaldehyde at 150 degrees C.

Series
Journal of Physics Conference Series, ISSN 1742-6588 ; 559
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-237084 (URN)10.1088/1742-6596/559/1/012012 (DOI)000346420600012 ()
Conference
INERA Workshop on Transition Metal Oxides as Functional Layers in Smart windows and Water Splitting Devices / Parallel session of the 18th International School on Condensed Matter Physics, sep 4-6, 2014, Varna, Bulgaria
Available from: 2014-11-26 Created: 2014-11-26 Last updated: 2016-10-14Bibliographically approved
Organisations

Search in DiVA

Show all publications