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Bayrak Pehlivan, IlknurORCID iD iconorcid.org/0000-0002-4362-6148
Alternative names
Publications (10 of 39) Show all publications
Sorar, I., Rojas González, E. A., Bayrak Pehlivan, I., Granqvist, C. G. & Niklasson, G. (2019). Electrochromism of W–Ti Oxide Thin Films: Cycling Durability,Potentiostatic Rejuvenation, and Modelling of Electrochemical Degradation. Journal of the Electrochemical Society, 166(15), H795-H801
Open this publication in new window or tab >>Electrochromism of W–Ti Oxide Thin Films: Cycling Durability,Potentiostatic Rejuvenation, and Modelling of Electrochemical Degradation
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2019 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 166, no 15, p. H795-H801Article in journal (Refereed) Published
Abstract [en]

Thin films of electrochromicWoxide and W–Ti oxide were prepared by reactive DC magnetron sputtering and were cycled voltammetrically in an electrolyte of lithium perchlorate in propylene carbonate. Film degradation was studied for up to 500 voltammetric cycles in voltage ranges between 1.5–4.0 and 2.0–4.0 V vs. Li/Li+. Optically and electrochemically degraded films were subjected to potentiostatic posttreatment at 6.0 V vs. Li/Li+ to achieve ion de-trapping and rejuvenation so that the films partly regained their original properties. Ti incorporation and potentiostatic posttreatment jointly yielded superior electrochromic properties provided the lower limit of the voltage range was above 1.6–1.7 V vs. Li/Li+. Degradation dynamics for as-deposited and rejuvenated thin films was modeled successfully by power-law kinetics; this analysis indicated coexistence of two degradation mechanisms, one based on dispersive chemical kinetics and operating universally and another, of unknown origin, rendered inactive by rejuvenation. The results of the present study are of large interest for the development of electrochromic devices with exceptional durability.

Place, publisher, year, edition, pages
Electrochemical Society, 2019
National Category
Condensed Matter Physics
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-397482 (URN)DOI: 10.1149/2.0421915jes (DOI)000494283100001 ()
Funder
Swedish Research Council, VR-2016-03713Swedish Research Council, 2017-00646-9Swedish Foundation for Strategic Research , RIF14-0053
Available from: 2019-11-20 Created: 2019-11-20 Last updated: 2019-11-22Bibliographically approved
Bayrak Pehlivan, I., Arvizu, M. A., Qiu, Z., Niklasson, G. A. & Edvinsson, T. (2019). Impedance Spectroscopy Modeling of Nickel–Molybdenum Alloys on Porous and Flat Substrates for Applications in Water Splitting. The Journal of Physical Chemistry C, 123(39), 23890-23897
Open this publication in new window or tab >>Impedance Spectroscopy Modeling of Nickel–Molybdenum Alloys on Porous and Flat Substrates for Applications in Water Splitting
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2019 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 39, p. 23890-23897Article in journal (Refereed) Published
Abstract [en]

Hydrogen production by splitting water using electrocatalysts powered by renewable energy from solar or wind plants is one promising alternative to produce a carbon-free and sustainable fuel. Earth-abundant and nonprecious metals are, here, of interest as a replacement for scarce and expensive platinum group catalysts. Ni–Mo is a promising alternative to Pt, but the type of the substrate could ultimately affect both the initial growth conditions and the final charge transfer in the system as a whole with resistive junctions formed in the heterojunction interface. In this study, we investigated the effect of different substrates on the hydrogen evolution reaction (HER) of Ni–Mo electrocatalysts. Ni–Mo catalysts (30 atom % Ni, 70 atom % Mo) were sputtered on various substrates with different porosities and conductivities. There was no apparent morphological difference at the surface of the catalytic films sputtered on the different substrates, and the substrates were classified from microporous to flat. The electrochemical characterization was carried out with linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in the frequency range 0.7 Hz–100 kHz. LSV measurements were carried out at direct current (DC) potentials between 200 and −400 mV vs the reversible hydrogen electrode (RHE) in 1 M NaOH encompassing the HER. The lowest overpotentials for HER were obtained for films on the nickel foam at all current densities (−157 mV vs RHE @ 10 mA cm–2), and the overpotentials increased in the order of nickel foil, carbon cloth, fluorine-doped tin oxide, and indium tin oxide glass. EIS data were fitted with two equivalent circuit models and compared for different DC potentials and different substrate morphologies and conductivities. By critical evaluation of the data from the models, the influence of the substrates on the reaction kinetics was analyzed in the high- and low-frequency regions. In the high-frequency region, a strong substrate dependence was seen and interpreted with a Schottky-type barrier, which can be rationalized as being due to a potential barrier in the material heterojunctions or a resistive substrate–film oxide/hydroxide. The results highlight the importance of substrates, the total charge transfer properties in electrocatalysis, and the relevance of different circuit components in EIS and underpin the necessity to incorporate high-conductivity, chemically inert, and work-function-matched substrate–catalysts in the catalyst system.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Materials Chemistry
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-395176 (URN)10.1021/acs.jpcc.9b02714 (DOI)000489086300017 ()
Funder
EU, Horizon 2020Swedish Research Council, VR-2015-03814Swedish Research Council, VR-2016-03713
Available from: 2019-10-14 Created: 2019-10-14 Last updated: 2019-12-12Bibliographically approved
Niklasson, G., Qiu, Z., Bayrak Pehlivan, I. & Edvinsson, T. (2019). Impedance spectroscopy of water splitting reactions on nanostructured metal-based catalysts. In: Functional Materials and Nanotechnologies (FM&NT 2018): . Paper presented at 12th International Scientific Conference on Functional Materials and Nanotechnologies (FM&NT), OCT 02-05, 2018, Riga, Latvia. Institute of Physics Publishing (IOPP), Article ID 012005.
Open this publication in new window or tab >>Impedance spectroscopy of water splitting reactions on nanostructured metal-based catalysts
2019 (English)In: Functional Materials and Nanotechnologies (FM&NT 2018), Institute of Physics Publishing (IOPP), 2019, article id 012005Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Hydrogen production by water splitting using nanomaterials as electrocatalysts is a promising route enabling replacement of fossil fuels by renewable energy sources. In particular, the development of inexpensive non-noble metal-based catalysts is necessary in order to replace currently used expensive Pt-based catalysts. We report a detailed impedance spectroscopy study of Ni-Mo and Ni-Fe based electrocatalytic materials deposited onto porous and compact substrates with different conductivities. The results were interpreted by a critical comparison with equivalent circuit models. The reaction resistance displays a strong dependence on potential and a lower substrate dependence. The impedance behaviour can also provide information on the dominating reaction mechanism. An optimized Ni-Fe based catalyst showed very promising properties for applications in water electrolysis.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2019
Series
IOP Conference Series-Materials Science and Engineering, ISSN 1757-8981 ; 503:1
National Category
Engineering and Technology Physical Chemistry
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-369729 (URN)10.1088/1757-899X/503/1/012005 (DOI)000471150800005 ()
Conference
12th International Scientific Conference on Functional Materials and Nanotechnologies (FM&NT), OCT 02-05, 2018, Riga, Latvia
Funder
Swedish Research Council, VR-2016-03713Swedish Research Council, VR-2015-03814EU, Horizon 2020
Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2020-01-08Bibliographically approved
Bayrak Pehlivan, I., Edoff, M., Stolt, L. & Edvinsson, T. (2019). Optimum Band Gap Energy of ((Ag),Cu)(InGa)Se2 Materials for Combination with NiMo–NiO Catalysts for Thermally Integrated Solar-Driven Water Splitting Applications. Energies, 12, Article ID 4064.
Open this publication in new window or tab >>Optimum Band Gap Energy of ((Ag),Cu)(InGa)Se2 Materials for Combination with NiMo–NiO Catalysts for Thermally Integrated Solar-Driven Water Splitting Applications
2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, article id 4064Article in journal (Refereed) Published
Abstract [en]

Solar-driven water splitting is considered one of the promising future routes to generate fuel in a sustainable way. A carbon-free solar fuel, molecular hydrogen, can here be produced along two different but intimately related routes, photoelectrochemical (PEC) water splitting or photovoltaic electrolysis (PV-electrolysis), where the latter builds on well-established solar cell and electrolysis materials with high efficiency. The PV-electrolysis approach is also possible to construct from an integrated PEC/PV-system avoiding dc-dc converters and enabling heat exchange between the PV and electrolyzer part, to a conventionally wired PV-electrolysis system. In either case, the operating voltage at a certain current needs to be matched with the catalyst system in the electrolysis part. Here, we investigate ((Ag),Cu)(In,Ga)Se-2 ((A)CIGS)-materials with varying Ga-content modules for combination with NiMo-NiO catalysts in alkaline water splitting. The use of (A)CIGS is attractive because of the low cost-to-performance ratio and the possibility to optimize the performance of the system by tuning the band gap of (A)CIGS in contrast to Si technology. The band gap tuning is possible by changing the Ga/(Ga + In) ratio. Optoelectronic properties of the (A)CIGS materials with Ga/(Ga + In) ratios between 0.23 and 0.47 and the voltage and power output from the resulting water splitting modules are reported. Electrolysis is quantified at temperatures between 25 and 60 degrees C, an interval obtainable by varying the thermal heat exchange form a 1-sun illuminated PV module and an electrolyte system. The band gaps of the (A)CIGS thin films were between 1.08 to 1.25 eV and the three-cell module power conversion efficiencies (PCE) ranged from 16.44% with 1.08 eV band gap and 19.04% with 1.17 eV band gap. The highest solar-to-hydrogen (STH) efficiency was 13.33% for the (A)CIGS-NiMo-NiO system with 17.97% module efficiency and electrolysis at 60 degrees C compared to a STH efficiency of 12.98% at 25 degrees C. The increase in STH efficiency with increasing temperature was more notable for lower band gaps as these are closer to the overpotential threshold for performing efficient solar-driven catalysis, while only a modest improvement can be obtained by utilizing thermal exchange for a band gap matched PV-catalysts system. The results show that usage of cost-effective and stable thin film PV materials and earth abundant catalysts can provide STH efficiencies beyond 13% even with PV modules with modest efficiency.

National Category
Engineering and Technology Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-400938 (URN)10.3390/en12214064 (DOI)000512340000043 ()
Available from: 2020-01-03 Created: 2020-01-03 Last updated: 2020-03-04Bibliographically approved
Granqvist, C. G., Arvizu, M. A., Bayrak Pehlivan, I., Qu, H.-Y., Wen, R.-T. & Niklasson, G. A. (2018). Electrochromic materials and devices for energy efficiency and human comfort in buildings: A critical review. Electrochimica Acta, 259, 1170-1182
Open this publication in new window or tab >>Electrochromic materials and devices for energy efficiency and human comfort in buildings: A critical review
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2018 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 259, p. 1170-1182Article, review/survey (Refereed) Published
Abstract [en]

Electrochromic (EC) materials can be integrated in thin-film devices and used for modulating optical transmittance. The technology has recently been implemented in large-area glazing (windows and glass facades) in order to create buildings which combine energy efficiency with good indoor comfort. This critical review describes the basics of EC technology, provides a case study related to EC foils for glass lamination, and discusses a number of future aspects. Ample literature references are given with the object of providing an easy entrance to the burgeoning research field of electrochromics.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Materials Chemistry Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-350203 (URN)10.1016/j.electacta.2017.11.169 (DOI)000423968600129 ()
Available from: 2018-05-08 Created: 2018-05-08 Last updated: 2020-04-14Bibliographically approved
Granqvist, C. G., Bayrak Pehlivan, I. & Niklasson, G. A. (2018). Electrochromics on a roll: Web-coating and lamination for smart windows. Paper presented at 60th Annual Technical Conference of the Society-of-Vacuum-Coaters (SVC), APR 29-MAY 04, 2017, Providence, RI. Surface & Coatings Technology, 336, 133-138
Open this publication in new window or tab >>Electrochromics on a roll: Web-coating and lamination for smart windows
2018 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 336, p. 133-138Article in journal (Refereed) Published
Abstract [en]

Electrochromic devices can vary the throughput of solar energy and visible light in glazing for buildings, which are then able to combine improved energy efficiency with enhanced indoor comfort and convenience. The technology can be implemented in different ways; here the focus is on web-coated devices which can be delivered, on a roll or in the form of large sheets, as foil for glass lamination. The present paper introduces the technology, discusses web-coating versus in-line glass coating, mentions lamination, and touches on possibilities to combine electrochromism with other functionalities such as thermochromic control of solar energy transmittance. The purpose of the paper is to give a tutorial overview of a technology that is currently introduced in buildings.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2018
Keywords
Web-coated electrochromic device, Electrolyte functionalization, Infrared blocking, Thermochromism
National Category
Materials Chemistry Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-348848 (URN)10.1016/j.surfcoat.2017.08.006 (DOI)000425478000021 ()
Conference
60th Annual Technical Conference of the Society-of-Vacuum-Coaters (SVC), APR 29-MAY 04, 2017, Providence, RI
Available from: 2018-04-20 Created: 2018-04-20 Last updated: 2020-04-16Bibliographically approved
Saygili, Y., Turren-Cruz, S.-H., Olthof, S., Saes, B. W., Bayrak Pehlivan, I., Saliba, M., . . . Tress, W. (2018). Planar Perovskite Solar Cells with High Open-CircuitVoltage Containing a Supramolecular Iron Complex as HoleTransport Material Dopant. ChemSusChem, 19, 1-9
Open this publication in new window or tab >>Planar Perovskite Solar Cells with High Open-CircuitVoltage Containing a Supramolecular Iron Complex as HoleTransport Material Dopant
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2018 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 19, p. 1-9Article in journal (Refereed) Published
Abstract [en]

n perovskite solar cells (PSCs), the most commonly used hole transport material (HTM) is spiro-OMeTAD, which is typically doped by metalorganic complexes, for example, based on Co, to improve charge transport properties and thereby enhance the photovoltaic performance of the device. In this study, we report a new hemicage-structured iron complex, 1,3,5-tris(5'-methyl-2,2'-bipyridin-5-yl)ethylbenzene Fe(III)-tris(bis(trifluoromethylsulfonyl)imide), as a p-type dopant for spiro-OMeTAD. The formal redox potential of this compound was measured as 1.29 V vs. the standard hydrogen electrode, which is slightly (20 mV) more positive than that of the commercial cobalt dopant FK209. Photoelectron spectroscopy measurements confirm that the iron complex acts as an efficient p-dopant, as evidenced in an increase of the spiro-OMeTAD work function. When fabricating planar PSCs with the HTM spiro-OMeTAD doped by 5 mol % of the iron complex, a power conversion efficiency of 19.5 % (AM 1.5G, 100 mW cm-2 ) is achieved, compared to 19.3 % for reference devices with FK209. Open circuit voltages exceeding 1.2 V at 1 sun and reaching 1.27 V at 3 suns indicate that recombination at the perovskite/HTM interface is low when employing this iron complex. This work contributes to recent endeavors to reduce recombination losses in perovskite solar cells.

National Category
Condensed Matter Physics Energy Systems
Identifiers
urn:nbn:se:uu:diva-369254 (URN)10.1002/cphc.201800032 (DOI)
Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2019-02-13Bibliographically approved
Pati, P. B., Damas, G., Tian, L., Fernandes, D. L. A., Zhang, L., Bayrak Pehlivan, I., . . . Tian, H. (2017). An experimental and theoretical study of an efficient polymer nano-photocatalyst for hydrogen evolution. Energy & Environmental Science, 10(6), 1372-1376
Open this publication in new window or tab >>An experimental and theoretical study of an efficient polymer nano-photocatalyst for hydrogen evolution
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2017 (English)In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 10, no 6, p. 1372-1376Article in journal (Refereed) Published
Abstract [en]

In this work, we report a highly efficient organic polymer nano-photocatalyst for light driven proton reduction. The system renders an initial rate of hydrogen evolution up to 50 +/- 0.5 mmol g(-1) h(-1), which is the fastest rate among all other reported organic photocatalysts. We also experimentally and theoretically prove that the nitrogen centre of the benzothiadiazole unit plays a crucial role in the photocatalysis and that the Pdots structure holds a close to ideal geometry to enhance the photocatalysis.

Keywords
CATALYSTS; H-2; SYSTEM; ENVIRONMENTAL SCIENCES; CELLS; CONJUGATED POLYMERS; ENERGY & FUELS; ARTIFICIAL PHOTOSYNTHESIS; WATER; ENGINEERING, CHEMICAL; GENERATION; CHEMISTRY, MULTIDISCIPLINARY; VISIBLE-LIGHT
National Category
Polymer Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-332949 (URN)10.1039/c7ee00751e (DOI)000403320300009 ()
Funder
Knut and Alice Wallenberg FoundationSwedish Energy AgencyÅForsk (Ångpanneföreningen's Foundation for Research and Development)Stiftelsen Olle Engkvist ByggmästareStandUp
Available from: 2017-11-02 Created: 2017-11-02 Last updated: 2019-12-03Bibliographically approved
Bayrak Pehlivan, I., Marsal, R., Pehlivan, E., Runnerstrom, E. L., Milliron, D. J., Granqvist, C.-G. & Niklasson, G. (2014). Electrochromic Devices with Polymer Electrolytes Functionalized by SiO2 and In2O3:Sn Nanoparticles: Rapid Coloration/Bleaching Dynamics and Strong Near-Infrared Absorption. Solar Energy Materials and Solar Cells, 126, 241-247
Open this publication in new window or tab >>Electrochromic Devices with Polymer Electrolytes Functionalized by SiO2 and In2O3:Sn Nanoparticles: Rapid Coloration/Bleaching Dynamics and Strong Near-Infrared Absorption
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2014 (English)In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 126, p. 241-247Article in journal (Refereed) Published
National Category
Engineering and Technology Nano Technology
Identifiers
urn:nbn:se:uu:diva-284199 (URN)
Available from: 2016-04-15 Created: 2016-04-15 Last updated: 2018-08-30
Pehlivan, I. B., Marsal, R., Pehlivan, E., Runnerstrom, E. L., Milliron, D. J., Granqvist, C.-G. & Niklasson, G. A. (2014). Electrochromic Devices with Polymer Electrolytes Functionalized by SiO2 and In2O3:Sn Nanoparticles: Rapid Coloring/Bleaching Dynamics and Strong Near-Infrared Absorption. Paper presented at 10th International Meeting on Electrochromism (IME), Holland, MI, August 12-16, 2012. Solar Energy Materials and Solar Cells, 126, 241-247
Open this publication in new window or tab >>Electrochromic Devices with Polymer Electrolytes Functionalized by SiO2 and In2O3:Sn Nanoparticles: Rapid Coloring/Bleaching Dynamics and Strong Near-Infrared Absorption
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2014 (English)In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 126, p. 241-247Article in journal (Refereed) Published
Abstract [en]

We studied the optical properties and coloring/bleaching dynamics of electrochromic devices based on tungsten oxide and nickel oxide and incorporating polymer electrolytes functionalized by adding about one percent of nanoparticles of SiO2 (fumed silica) or In2O3:Sn. SiO2 improved the coloring/bleaching dynamics and In2O3:Sn quenched the near-infrared transmittance. Both of these effects can be important in electrochromic smart windows, and our results point at the advantage of a polymer laminated construction over a monolithic one.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
urn:nbn:se:uu:diva-204448 (URN)10.1016/j.solmat.2013.06.010 (DOI)000338395100035 ()
Conference
10th International Meeting on Electrochromism (IME), Holland, MI, August 12-16, 2012
Available from: 2013-08-05 Created: 2013-08-05 Last updated: 2017-12-06Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-4362-6148

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