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  • 1.
    Arvizu, Miguel. A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, C.-G.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromism in Sputter Deposited W1-yMoyO3 Thin Films2016In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, no 012005, p. 1-6Article in journal (Refereed)
  • 2.
    Arvizu, Miguel A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes G.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Rejuvenation of degraded electrochromic MoO3 thin films made by DC magnetron sputtering: Preliminary results2016In: Journal of Physics: Conference Series, Institute of Physics Publishing (IOPP), 2016, Vol. 764, article id 012009Conference paper (Refereed)
    Abstract [en]

    Molybdenum oxide thin films were deposited by reactive DC magnetron sputtering and were subjected to voltammetric cycling in an electrolyte comprised of lithium perchlorate in propylene carbonate. The films were heavily degraded during 20 voltammetric cycles in an extended voltage range. The films were subsequently rejuvenated by use of potentiostatic treatments under different voltages during 20 hours. Optical changes were recorded during the electrochemical degradation and ensuing rejuvenation.

  • 3.
    Arvizu, Miguel A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromic dc sputtered W1-x-y Moy Tix O3 thin films:: Optical properties and durability.2016Conference paper (Refereed)
    Abstract [en]

    The key component in an electrochromic (EC) device is its primary EC thin film. The outstanding intrinsic ECproperties of tungsten oxide (WO3) make this material the best option available for the cathodic layer in an ECdevice. Nevertheless much research remains in order to optimize WO3 with regard to optical properties, durability,etc. It is well known that addition of titanium (Ti) into the matrix of WO3 increases significantly the resistance of the film to electrochemical cycling both under norma loperation and during accelerated aging in extended voltage ranges [1]. On the other hand, using molybdenum (Mo) as an additive in small concentrations helps to improve the color rendering by shifting th eposition of the maximum of the coloration band to higher energies [2]. The present work reports our recent investigations on thin films of mixed oxides with a focus on ways to optimize tungsten oxide thin films regarding both their durability and color by the addition of Ti and Mo. The films were deposited by reactive DC cosputtering from Mo and W-Ti alloy targets. Cyclic voltammetry, in a three-electrode system consisting of the film and lithium foils, was performed in a solution 1 MLiClO4 in propylene carbonate (Li–PC) as electrolyte. Insitu and ex-situ optical characterization was done for the EC films, and the transmittance switching and coloration efficiency were determined. Durability was studied by analyzing how the charge density evolved and how rapidly the transmittance modulation deteriorated during cycling for the different concentrations of Mo and Ti .

    References

    [1] M.A. Arvizu, C.A. Triana, B.I. Stefanov, C.G.Granqvist , G.A. Niklasson, “Electrochromism in SputterdepositedW-Ti Oxide Films: Durability Enhancement dueto Ti”, Solar Energy Materials & Solar Cells 125 (2014)184-189 (and references therein).

    [2] M.A. Arvizu, C.G. Granqvist and G.A. Niklasson,“Electrochromism in sputter deposited W1–yMoyO3 thinfilms”, Journal of Physics: Conference Series 682 (2016)012005 (and references therein).

  • 4.
    Arvizu, Miguel A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromism in DC sputtered W1-yMoyO3 thin films2015In: INERA Conference 2015: Light in Nanoscience and Nanotechnolog, Institute of Physics (IOP), 2015, article id 012005Conference paper (Refereed)
    Abstract [en]

    Electrochromic (EC) properties of tungsten–molybdenum oxide (W1–yMoyO3) thin films were investigated. The films were deposited on indium tin oxide covered glass by reactive DC sputtering from tungsten and molybdenum targets. Elemental compositions of the W1–yMoyO3 films were determined by Rutherford back scattering. Voltammetric cycling was performed in an electrolyte of 1 M LiClO4 in propylene carbonate. The increase in molybdenum content in the EC films caused both a shift towards higher energies and a quenching of the value of the maximum of the coloration band, as compared with WO3 EC films. Durability was also diminished for W1–yMoyO3 EC films.

  • 5.
    Arvizu, Miguel A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Ctr Invest & Estudios Avanzados IPN, Dept Fis, AP 14740, Mexico City 07360, DF, Mexico.
    Morales-Luna, M.
    Ctr Invest & Estudios Avanzados IPN, Programa Nanociencias & Nanotecnol, AP 14740, Mexico City 07360, DF, Mexico..
    Perez-Gonzalez, M.
    Ctr Invest & Estudios Avanzados IPN, Dept Fis, AP 14740, Mexico City 07360, DF, Mexico..
    Campos-Gonzalez, E.
    Univ Autonoma Queretaro, Fac Quim Mat, Queretaro, Mexico..
    Zelaya-Angel, O.
    Ctr Invest & Estudios Avanzados IPN, Dept Fis, AP 14740, Mexico City 07360, DF, Mexico..
    Tomas, S. A.
    Ctr Invest & Estudios Avanzados IPN, Dept Fis, AP 14740, Mexico City 07360, DF, Mexico..
    Influence of Thermal Annealings in Argon on the Structural and Thermochromic Properties of MoO3 Thin Films2017In: International journal of thermophysics, ISSN 0195-928X, E-ISSN 1572-9567, Vol. 38, no 4, article id 51Article in journal (Refereed)
    Abstract [en]

    The effect of thermal annealing in an inert atmosphere (argon) on the structural and thermochromic properties of MoO3 thin films was investigated. MoO3 thin films were deposited by thermal evaporation in vacuum of MoO3 powders. X-ray diffraction patterns of the films showed the presence of the monoclinic Magneli phase Mo9O26 for annealing temperatures above 250 degrees C. Absorbance spectra of the films annealed in argon indicated that their thermochromic response increases with the annealing temperature in the analyzed range (23 degrees C-300 degrees C), a result opposite to the case of thermal annealings in air, for which case the thermochromic response shows a maximum value around 200 degrees C-225 degrees C and decreases for higher temperatures. These results are explained in terms of a higher density of oxygen vacancies formed upon thermal treatments in inert atmospheres.

  • 6.
    Arvizu, Miguel A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromic W(1-x-y)Ti(x)lo(y)O(3) Thin Films Made by Sputter Deposition: Large Optical Modulation, Good Cycling Durability, and Approximate Color Neutrality2017In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 29, no 5, p. 2246-2253Article in journal (Refereed)
    Abstract [en]

    Tungsten oxide thin films are used in electrochromic devices such as variable-transmittance "smart windows" for energy efficient buildings with good indoor comfort. Two long-standing issues for WO3 thin films are their limited durability under electrochemical cycling and their blue color in transmission. Here, we show that both of these problems can be significantly alleviated by additions of titanium and molybdenum. We found that similar to 300 nm-thick films of sputter deposited W1-x-yTixMoyO3 are able to combine a midluminous transmittance modulation of 0.4 similar to 70% with good color neutrality and durability under extended electrochemical cycling. The Ti content should be similar to 10 at. % in order to achieve durability without impairing transmittance modulation significantly, and the Mo content preferably should be no larger than 6 at. % in order to maintain durability. Hence, our results give clear guidelines for making three-component mixed-oxide thin films that are suitable for electrochromic "smart windows".

  • 7.
    Arvizu, Miguel A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Univ Politecn Chiapas, Campus Suchiapa,Carretera Tuxtla Gutierrez, Suchiapa 29150, Chiapas, Mexico..
    Qu, Hui-Ying
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochemical pretreatment of electrochromic WO3 films gives greatly improved cycling durability2018In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 653, p. 1-3Article in journal (Refereed)
    Abstract [en]

    Electrochromic WO3 thin films have important applications in devices such as smart windows for energy-efficient buildings. Long-term electrochemical cycling durability of these films is essential and challenging. Here we investigate reactively sputter-deposited WO3 films, backed by indium-tin oxide layers and immersed in electrolytes of LiClO4 in propylene carbonate, and demonstrate unprecedented electrochemical cycling durability after straight-forward electrochemical pretreatments by the application of a voltage of 6 V vs. Li/Li+ for several hours.

  • 8.
    Arvizu, Miguel A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Triana, Carlos A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Stefanov, Bozhidar I
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromism in sputter-deposited W-Ti oxide films: Durability enhancement due to Ti2014In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 125, p. 184-189Article in journal (Refereed)
    Abstract [en]

    Thin films of W-Ti oxide were prepared by reactive DC magnetron sputtering and were characterized by Rutherford bathcattering spectrometry, X-ray diffraction, scanning electron microscopy and atomic force microscopy. The electrochromic properties were studied by cyclic voltammetry in an electrolyte of lithium perchlorate in propylene carbonate and by optical transmittance measurements. The addition of Ti significantly promoted the amorphous nature of the films and stabilized their electrochemical cycling performance and dynamic range for electrochromism. (C) 2014 Elsevier B.V. All rights reserved.

  • 9.
    Arvizu, Miguel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wen, Rui-Tao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Klemberg-Sapieha, Jolanta Ewa
    Martinu, Ludvik
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Galvanostatic ion de-trapping rejuvenates oxide thin films2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 48, p. 26387-26390Article in journal (Refereed)
    Abstract [en]

    Ion trapping under charge insertion-extraction is well-known to degrade the electrochemical performance of oxides. Galvano-static treatment was recently shown capable to rejuvenate the oxide, but the detailed mechanism remained uncertain. Here we report on amorphous electrochromic (EC) WO3 thin films prepared by sputtering and electrochemically cycled in a lithium-containing electrolyte under conditions leading to severe loss of charge exchange capacity and optical modulation span. Time-of-flight elastic recoil detection analysis (ToF-ERDA) documented pronounced Li+ trapping associated with the degradation of the EC properties and, importantly, that Li+ detrapping, caused by a weak constant current drawn through the film for some time, could recover the original EC performance. Thus, ToF-ERDA provided direct and unambiguous evidence for Li+ detrapping.

  • 10.
    Baloukas, Bill
    et al.
    Polytech Montreal, Dept Engn Phys, Montreal.
    Arvizu, Miguel A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wen, Rui-Tao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Vernhes, Richard
    Polytech Montreal, Dept Engn Phys, Montreal.
    Klemberg-Sapieha, Jolanta E.
    Polytech Montreal, Dept Engn Phys, Montreal.
    Martinu, Ludvik
    Polytech Montreal, Dept Engn Phys, Montreal.
    Galvanostatic Rejuvenation of Electrochromic WO3 Thin Films: Ion Trapping and Detrapping Observed by Optical Measurements and by Time-of-Flight Secondary Ion Mass Spectrometry2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 20, p. 16996-17002Article in journal (Refereed)
    Abstract [en]

    Electrochromic (EC) smart windows are able to decrease our energy footprint while enhancing indoor comfort and convenience. However, the limited durability of these windows, as well as their cost, result in hampered market introduction. Here, we investigate thin films of the most widely studied EC material, WO3. Specifically, we combine optical measurements (using spectrophotometry in conjunction with variable-angle spectroscopic ellipsometry) with time-of-flight secondary ion mass spectrometry and atomic force microscopy. Data were taken on films in their as-deposited state, after immersion in a Li-ion-conducting electrolyte, after severe degradation by harsh voltammetric cycling and after galvanostatic rejuvenation to regain the original EC performance. Unambiguous evidence was found for the trapping and detrapping of Li ions in the films, along with a thickness increase or decrease during degradation and rejuvenation, respectively. It was discovered that (i) the trapped ions exhibited a depth gradient; (ii) following the rejuvenation procedure, a small fraction of the Li ions remained trapped in the film and gave rise to a weak short-wavelength residual absorption; and (iii) the surface roughness of the film was larger in the degraded state than in its virgin and rejuvenated states. These data provide important insights into the degradation mechanisms of EC devices and into means of achieving improved durability.

  • 11.
    Boyadjiev, Stefan I.
    et al.
    “Georgi Nadjakov” Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko chaussee Blvd., 1784 Sofia, Bulgaria.
    Stefan, Nicolaie
    National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov, Romania.
    Stan, George
    National Institute of Materials Physics, 405A Atomistilor Street, Magurele-Ilfov, RO-077125, Romania.
    Arvizu, Miguel
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Szilágyi, Imre M.
    MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4., H-1111, Budapest, Hungary and Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, 4 Műegyetem rakpart, H-1111, Budapest, Hungary.
    Visan, Anita
    National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov, Romania.
    Mihailescu, Natalia
    National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov, Romania.
    Mihailescu, Ion N.
    National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Street, RO-77125, Magurele-Ilfov, Romania.
    Besleaga, Cristina
    National Institute of Materials Physics, 405A Atomistilor Street, Magurele-Ilfov, RO-077125, Romania.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gesheva, Kostadinka A.
    Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, 72 Tzarigradsko chaussee Blvd., 1784 Sofia, Bulgaria.
    Study of the electrochromic properties of MAPLE and PLD deposited WO3 thin films2017Conference paper (Refereed)
    Abstract [en]

    Tungsten trioxide (WO3) thin films were grown by matrix assisted pulsed laser evaporation (MAPLE) and pulsed laser deposition (PLD), and their properties were investigated for electrochromic applications. The structure, morphology and optical properties of these MAPLE and PLD grown from monoclinic WO3 nano-sized particles WO3 thin films were also studied. A KrF* excimer (λ=248 nm, ζFWHM=25 ns) laser source was used in all experiments. The films were studied by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD) and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetry measurements were also performed in glove box with Ar atmosphere towards Li electrode, and the coloring and bleaching states were investigated. The morpho-structural investigations disclosed the synthesis of single-phase monoclinic WO3 films consisting of crystalline nano-grains embedded in an amorphous matrix. All thin films showed good electrochromic properties - strong coloration and fast and full bleaching. The effect was observed for many cycles, the strong coloration and full bleaching being preserved. These results are promising for future application of MAPLE and PLD deposited WO3 thin films in the development of electrochromic devices.

  • 12.
    Gesheva, Kostadinka
    et al.
    Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences.
    Arvizu, Miguel A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Bodurov, Georgij
    Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences.
    Ivanova, Tatiana
    Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Iliev, M
    Institute of Solid State Physics, Bulgarian Academy of Sciences.
    Vlakhov, T
    Institute of Solid State Physics, Bulgarian Academy of Sciences.
    Terzijska, P
    Institute of Solid State Physics, Bulgarian Academy of Sciences.
    Popkirov, G
    Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences.
    Abrashev, M
    Faculty of Physics, Sofia University, Bulgaria.
    Boyadjiev, Stefan
    Institute of Solid State Physics, Bulgarian Academy of Sciences.
    Jagerszki, G
    MTA-BME Technical Analytical Chemistry Research Group, Budapest, Hungary.
    Szilagyi, I M
    MTA-BME Technical Analytical Chemistry Research Group, Budapest, Hungary.
    Marinov, Yordan
    Institute of Solid State Physics, Bulgarian Academy of Sciences.
    Optical, structural and electrochromic properties of sputter deposited W-Mo oxide thin films2016In: INERA CONFERENCE: VAPOR PHASE TECHNOLOGIES FOR METAL OXIDE AND CARBON NANOSTRUCTURES, Institute of Physics Publishing (IOPP), 2016, Vol. 764, article id 012010Conference paper (Refereed)
    Abstract [en]

    Thin metal oxide films were investigated by a series of characterization techniques including impedance spectroscopy, spectroscopic ellipsometry, Raman spectroscopy, and Atomic Force Microscopy. Thin film deposition by reactive DC magnetron sputtering was performed at the Ångström Laboratory. W and Mo targets (5 cm diameter) and various oxygen gas flows were employed to prepare samples with different properties, whereas the gas pressure was kept constant at about 30 mTorr. The substrates were 5×5 cm2 plates of unheated glass pre-coated with ITO having a resistance of 40 ohm/sq. Film thicknesses were around 300nm as determined by surface profilometry. Newly acquired equipment was used to study optical spectra, optoelectronic properties, and film structure. Films of WO3 and of mixed W–Mo oxide with three compositions showed coloring and bleaching under the application of a small voltage. Cyclic voltammograms were recorded with a scan rate of 5 mV s–1. Ellipsometric data for the optical constants show dependence on the amount of MoOx in the chemical composition. Single MoOx film, and the mixed one with only 8% MoOx have the highest value of refractive index, and similar dispersion in the visible spectral range. Raman spectra displayed strong lines at wavenumbers between 780 cm–1 and 950 cm–1 related to stretching vibrations of WO3, and MoO3. AFM gave evidence for domains of different composition in mixed W-Mo oxide films.

  • 13.
    Granqvist, Claes Göran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, Miguel A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Bayrak Pehlivan, Ilknur
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Qu, Hui-Ying
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Harbin Institute of Technology, School of Chemistry and Chemical Engineering, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, Harbin, China.
    Wen, Rui-Tao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromic materials and devices for energy efficiency and human comfort in buildings: A critical review2018In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 259, p. 1170-1182Article, review/survey (Refereed)
    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.

  • 14.
    Morales-Luna, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Ctr Invest & Estudios Avanzados IPN, Dept Nanociencias & Nanotecnol, AP 14-740, Mexico City 07360, DF, Mexico..
    Arvizu, Miguel A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromic properties of W1-x-yNixTiyO3 thin films made by DC magnetron sputtering2016In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 615, p. 292-299Article in journal (Refereed)
    Abstract [en]

    We investigated the electrochromic properties of tungsten-nickel-titanium oxide (W1-x-yNixTiyO3) thin films. Special emphasis was put on W0.83-xNixTi0.17O3 since this composition gave the highest electrochemical durability. The films were deposited onto indium-tin oxide coated glass by reactive DC magnetron sputtering, and cyclic voltammetry as well as optical transmittance measurements were performed in an electrolyte of 1 M LiClO4 in propylene carbonate. The potential window was chosen so as to cause rapid degradation of the samples. Elemental compositions were obtained by Rutherford backscattering spectroscopy and structural information by X-ray diffraction. We verified that the titanium additive improved the electrochemical durability of tungsten-oxide-based films and also documented that a further addition of nickel was unable to enhance the EC performance to any significant degree.

  • 15.
    Morales-Luna, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Centro de Investigacion y de Estudios Avanzados de I.P.N..
    Arvizu, Miguel A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sputter deposited W1-x-yNixTiyO3 thin films: Electrochromic properties and durability2016In: INERA Conference: Book of Abstracts / [ed] Nesheva, D; Chamati, H; Genova, J; Gesheva, K; Ivanova, T; Szekeres, A, Institute of Physics (IOP), 2016, article id 012021Conference paper (Refereed)
    Abstract [en]

    Previous research demonstrated that a small amount of nickel enhances the coloration efficiency of tungsten-nickel oxide electrochromic (EC) thin films with respect to that of pure tungsten oxide (WO3) films. Furthermore the incorporation of titanium gives an improvement in the durability of tungsten-titanium oxide EC thin films. In this work we investigated the EC performance of tungsten-nickel-titanium oxide (W1-x-yNixTiyO3) EC thin films with emphasis on durability. The films were deposited on indium tin oxide covered glass by reactive dc sputtering from tungsten, tungsten-titanium alloy and nickel targets. Cyclic voltammetry was performed using 1 M LiClO4 in propylene carbonate as electrolyte. The voltage window was chosen to induce fast degradation of the samples within 80 cycles. Elemental compositions were obtained by Rutherford Backscattering Spectroscopy.

  • 16.
    Niklasson, G A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wen, Rui-Tao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Qu, Hui-Ying
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, M A
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Durability of electrochromic films: Ageing kinetics and rejuvenation2017In: ECS Transactions, ISSN 1938-5862, E-ISSN 1938-6737, p. 1659-1669Article in journal (Refereed)
  • 17.
    Niklasson, G A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wen, Rui-Tao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Qu, Hui-Ying
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, MA
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Durability of Electrochromic films: Ageing kinetics and rejuvenation2017In: Abstracts, 2017, Vol. 1843, p. 1-, article id MA2017Conference paper (Refereed)
  • 18.
    Niklasson, Gunnar A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wen, Rui-Tao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, Miguel A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Malmgren, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Pehlivan, Esat
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Morales-Luna, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochemical degradation and rejuvenation of electrochromic tungsten oxide thin films2016Conference paper (Refereed)
    Abstract [en]

    Tungsten oxide is the most widely used cathodic electrochromic material for smart window applications. One of the main challenges for smart window technology is to ensure the durability of the electrochromic devices over a service life of more than 20 years. Hence, in order to facilitate large-scale practical application of electrochromic materials, their degradation under operating conditions must be better understood and preferably prevented. In this paper we address these issues by three different approaches. First we show that the electrochemical ageing of electrochromic tungsten oxide, under stressed conditions, can be described by stretched exponential kinetics. The goal of such accelerated ageing studies is eventually to be able to predict service life using this empirical relationship. Secondly, we report on a recently discovered rejuvenation processes for restoring aged coatings to their initial state. During severe ageing of the coatings, Li ions are trapped in the film, and subsequently these ions can be released by application of a high electrochemical potential for a few hours. We estimate activation energies for the release process from chronoamperometric measurements during rejuvenation. Thirdly we address the issue of the growth of a solid-electrolyte interface. Impedance spectroscopy measurements on tungsten oxide films were used to obtain the interfacial charge transfer resistance. After the films had been subjected to low potentials known to induce degradation, the charge transfer resistance in the usual operating range showed a marked increase. This is interpreted as a signature of the development of a solid-electrolyte interface. A similar increase of the charge transfer resistance has been observed in electrochromic devices subjected to accelerated aging at an elevated temperature of 80oC for a thousand cycles.

  • 19.
    Niklasson, Gunnar A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Wen, Rui-Tao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Materials Processing Center, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
    Qu, Huiying
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, China.
    Arvizu, Miguel A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Durability of electrochromic films: Aging kinetics and rejuvenation2017In: ECS Transactions, Electrochemical Society, 2017, Vol. 77, p. 1659-1669Conference paper (Refereed)
    Abstract [en]

    A major challenge for energy-efficient smart window technology is to ensure the durability of electrochromic (EC) devices over aservice life of more than 20 years. In this paper, we report recent results from a fundamental study of the aging kinetics of EC tungsten oxide and nickel oxide thin films and describe electrochemical rejuvenation mechanisms that are able to restore the films to their initial state. The aging kinetics displays an approximate power-law decrease of the charge capacity as a function of cycle number. This decay of charge capacity can be understood in terms of models built on so-called dispersive chemical kinetics. Tungsten oxide and nickel oxide EC films can be rejuvenated by applying a high electrochemical potential or a small constant current. Trapped ions in the bulk or at the surface of the films can be released by these procedures.

  • 20.
    Qu, Hui-Yang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, MA
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, G A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Degradation and rejuvenation in electrochromic nickel oxide films2017In: Abstracts, 2017Conference paper (Refereed)
  • 21.
    Qu, Huiying
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, Miguel A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Degradation and rejuvenation in electrochromic nickel oxide films2017Conference paper (Refereed)
    Abstract [en]

    Because of the rapidly increasing energy consumption and the associated global environmental problems, it is necessary and urgent to develop renewable energy solutions.  In addition, materials that lead to more efficient use of energy are of high importance. Electrochromic (EC) materials can be part of the solution to the problem of energy efficiency in the built environment. EC materials have the ability to change their optical properties upon the application of a small electrical signal. They have great potential for energy-efficient buildings, low-power display devices and the photoelectrochromic devices which combine EC and the nanostructured TiO2 based solar cells.

    Nickel oxide is one of the most widely used anodic EC materials, which can also be used as the ion storage layer of EC devices. However, from the view of application, the poor cycling durability of nickel oxide limits the life of EC devices. Moreover, although it has been 30 years since it was found, the underlying coloration mechanism is still not understood. Thus, improving the EC performance of nickel oxide is as important as clarifying its coloration mechanism.

    Recently we have studied the ageing process of the nickel oxide film when cycling in different ranges (2-4 V, 1.7-4 V and 2-4.3 V vs. Li/Li+). The film decays faster as we expand the potential range. This can be quantified by the reducing optical modulation from the transmission spectra as well as the decreasing charge capacity calculated from cyclic voltammetry curves. However, the aged film can be rejuvenated and regain its initial highly reversible EC performance when the trapped Li+ ions are removed by an electrical stimulus. Moreover, this rejuvenation process can be repeated many times. In order to optimize our results, several electrochemical techniques including potentiostatic and galvanostatic methods with different experimental parameters have been applied. Results show that when potentiostatic technique is applied, 4.1V is high enough to extract the trapped Li+ ions to regain the initial EC performance, but it needs a long time (20 h) to run. However, only 20 min is needed using galvanostatic treatment. The potential can go up to 4.7 V at the end of the process, which provides a larger potential difference to the trapped Li+ ions in a short time, without affecting the structure and the performance of the films. Raman, X-ray diffraction, Rutherford Backscattering Spectrometry and Elastic Recoil Detection Analysis measurements have also been used to understand the degradation and rejuvenation processes. The discovery of a rejuvenation process in nickel oxide is of interest for the long-time durability for practical EC devices and may also have implications for other energy research fields such as batteries and supercapacitors.

  • 22.
    Qu, Hui-Ying
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Harbin Institute of Technology, School of Chemistry and Chemical Engineering, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Arvizu, Miguel A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Qiu, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Cindemir, Umut
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochemical Rejuvenation of Anodically Coloring Electrochromic Nickel Oxide Thin Films2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, no 9, p. 42420-42424Article in journal (Refereed)
    Abstract [en]

    Nickel oxide thin films are of major importance as anodically coloring components in electrochromic smart windows with applications in energy-efficient buildings. However, the optical performance of these films degrades upon extended electrochemical cycling, which has hampered their implementation. Here, we use a potentiostatic treatment to rejuvenate degraded nickel oxide thin films immersed in electrolytes of LiClO4 in propylene carbonate. Time-of-flight elastic recoil detection analysis provided unambiguous evidence that both Li+ ions and chlorine-based ions participate in the rejuvenation process. Our work provides new perspectives for developing ion-exchange-based devices embodying nickel oxide.

  • 23.
    Wen, Rui-Tao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, Miguel A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Morales-Luna, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Ion Trapping and Detrapping in Amorphous Tungsten Oxide Thin Films Observed by Real-Time Electro-Optical Monitoring2016In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 28, no 13, p. 4670-4676Article in journal (Refereed)
    Abstract [en]

    Several technologies for energy saving and storage rely on ion exchange between electrodes and electrolytes. In amorphous electrode materials, a detailed knowledge of Li-ion intercalation is hampered by limited information about the structure and transport properties of the materials. Amorphous tungsten oxide is the most studied electrochromic material and suffers from ion trapping-induced degradation of charge capacity and optical modulation span upon extensive electrochemical cycling. In this paper, we investigate trapping and detrapping processes in connection with performance degradation and specifically use real-time electro-optical monitoring to identify different trap energy ranges pertinent to the ion-intercalated system. Evidence of three kinds of traps that degrade electrochromic tungsten oxide during ion intercalation is presented: (i) shallow traps that erode the colored state, (ii) deep traps that lower the bleached-state transmittance, and (iii) irreversible traps. Importantly, Li-ion detrapping from shallow and deep traps takes place by different processes: continuous Li-ion extraction is possible from shallow traps, whereas a certain release time must be exceeded for detrapping from deep traps. Our notions for ion trapping and detrapping, presented here, may serve as a starting point for discussing ion intercalation in various amorphous materials of interest for energy-related applications.

  • 24.
    Wen, Ruitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, Miguel A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromics for energy efficient buildings: Towards long-term durability and materials rejuvenation2016In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 290, p. 135-139Article in journal (Refereed)
    Abstract [en]

    Electrochromic devices such as "smart windows" for energy efficient windows must be durable enough for many years of practical use. Typical devices employ films based on W oxide and Ni oxide, and this paper surveys recent progress on durability-related issues for these materials. In the case of W oxide, we discuss the beneficial effects of Ti addition, and we describe recent and unexpected progress concerning galvanostatic rejuvenation of aged W oxide films. For Ni oxide, we report how charge exchange declination during extended voltammetric cycling can be modeled in terms of a power law.

  • 25.
    Wen, Rui-Tao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, Miguel A
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Progress in Electrochromics: Towards Long-Term Durability and Materials Rejuvenation for Oxide-Based Thin Films2015In: ECS Transactions, Electrochemical Society, 2015, Vol. 66 (31), p. 9-16Conference paper (Refereed)
    Abstract [en]

    Most electrochromic devices, such as “smart windows” for energy efficient glazings, must be durable enough for many years of service life. Typical constructions use films based on thin films of W oxide and Nioxide, and this paper summarizes progress on durability-related issues for these materials. For W oxide, we describe recent and unexpected progress on galvanostatic rejuvenation of aged W oxide films, and we also discuss the beneficial effects of Ti addition. For Ni oxide, we report how charge exchange declination during extended voltammetric cycling can be modeled in terms of a power law and also demonstrate how modest additions of Ir can dramatically extend the cycling durability.

  • 26.
    Wen, Ruitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Arvizu, Miguel A.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Niklasson, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Electrochromics for energy efficient buildings: Towards long-term durability and materials rejuvenation2015In: Surface and Coating Technology, ISSN 0257-8972, Vol. 278, p. 121-125Article in journal (Refereed)
    Abstract [en]

    Electrochromic devices such as “smart windows” for energy efficient windows must be durable enough for many years of practical use. Typical devices employ films based on W oxide and Ni oxide, and this paper surveys recent progress on durability-related issues for these materials. In the case of W oxide, we discuss the beneficial effects of Ti addition, and we describe recent and unexpected progress concerning galvanostatic rejuvenation of aged W oxide films. For Ni oxide, we report how charge exchange declination during extended voltammetric cycling can be modeled in terms of a power law.

1 - 26 of 26
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