Electrochromic tungsten oxide films prepared by sputtering: Optimizing cycling durability by judicious choice of deposition parameters

Atak, Gamze; Pehlivan, İlknur Bayrak; Montero, José; Granqvist, Claes G.; Niklasson, Gunnar A.

doi:10.1016/j.electacta.2020.137233

Cited by 28 publications

(20 citation statements)

References 68 publications

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“…In this study, WO 3 films of 350 nm exhibit larger charge capacities and optical transmittance modulation than other thicknesses, which are regarded as the significant electrochromic performance for the fabrication of an EC device. Compared with the work reported by Atak et al, [ 32 ] focusing on the role of deposition parameters on WO 3 films’ EC performance, WO 3 film in this study shows larger charge capacities (36.72 mC cm −2 ) and optical transmittance modulation (82.2%) than that in Atak's work (≈25 mC cm −2 and ≈76%), implying the feasibility of the deposition parameters in this study. Therefore, taking both EC layer's performance and production costs into account, 350 nm WO 3 film is considered to be the optimum design for fabricating an EC device in this study.…”

Section: Resultscontrasting

confidence: 53%

Thickness Dependence of WO₃ and NiO_x Thin Films in All‐Solid‐State Complementary Electrochromic Devices

et al. 2021

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WO3 and NiOx films with various thicknesses are deposited by reactive direct current magnetron sputtering. The relationship between film thickness and its electrochromic properties is investigated. A typical five‐layer corresponding complementary electrochromic device (CECD) is fabricated using optimized individual thicknesses of WO3 and NiOx, with UV‐curing Li+‐based polymer gel electrolyte. The results show that increasing film thickness can generally enhance the electrochemical and optical properties of WO3 and NiOx films. However, charge capacities and optical modulation drop when the thickness reaches a critical value, due to the dominance of the diffusion‐controlled process. 350 nm WO3 displays a wide optical modulation of 82.21% with a charge density of 36.72 mC cm−2, whereas 360 nm NiOx exhibits an optical modulation of 46.37% with a charge density of 7.66 mC cm−2. The CECD presents a fast response (bleaching and coloring time of 2.4 and 4 s, respectively) and good durability with optical modulation decreasing only 16% after 300 cycles. The current densities exhibit no significant decline till 3000 cycles during the stable period. The involvement of the diffusion‐controlled process in the electrochemical mechanism is substantiated by fitting chronoamperometry data, and the diffusion coefficient in the activated period is about three times larger than that in the stable period.

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Section: Resultscontrasting

confidence: 53%

Thickness Dependence of WO₃ and NiO_x Thin Films in All‐Solid‐State Complementary Electrochromic Devices

et al. 2021

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“…This is consistent with a recent extensive study on EC aWO 3 , which found switching times between a few seconds and a few tens of seconds. 61 However, it is important to realize that we study the dynamics under linear response conditions, while practical devices are usually operated under non-linear conditions, which is expected to lead to faster dynamics. Actually, switching times of large-area devices like smart windows are usually limited by the resistivity of the transparent conductors and the electrolyte.…”

Section: Journal Of Applied Physicsmentioning

confidence: 99%

Charge coloration dynamics of electrochromic amorphous tungsten oxide studied by simultaneous electrochemical and color impedance measurements

Rojas-González

Niklasson

2021

Journal of Applied Physics

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The coloration mechanisms in electrochromic systems can be probed by comparing the dynamics of the electrical and optical responses. In this paper, the linear frequency-dependent electrical and optical responses of an amorphous tungsten oxide thin film were measured simultaneously by a combination of two techniques-that is, electrochemical impedance spectroscopy (EIS) and the so-called color impedance spectroscopy. This was done at different bias potentials and their associated intercalation levels. Equivalent circuit fitting to the EIS spectra was used to extract the Faradaic components from the total impedance response. The latter were assigned to an intermediate adsorption step before the intercalation and to the diffusion of the electron-ion couple in the film. A quantity denoted complex optical capacitance was compared to the complex electrical capacitance-particularly, their expressions are related to the Faradaic processes. The coloration at low intercalation levels followed both the adsorption and diffusion phenomena. Conversely, the diffusion contribution was dominant at high intercalation levels and the adsorption one seemed to be negligible in this case. The complex spectra of perfectly synchronized electrical and optical responses are expected to differ only by a multiplying factor. This was the case at low intercalation levels, apart from small deviations at high frequencies. A clear departure from this behavior was observed as the intercalation level increased. A combination of frequency-dependent techniques, as presented here, can help to elucidate the dynamics of the coloration mechanisms in electrochromic materials at various conditions-for example, at different intercalation levels and optical wavelengths.

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“…A literature review of the most recent studies on smart windows is summarized in Table 1 . Although the majority of studies examine the influence of thermochromic [19][20][21][22][23][24][25][26], electrochromic [27][28][29][30], and gasochromic coatings [31][32][33] on building energy consumption, CO 2 emission, heading, and cooling load [34][35][36], only a few studies has focused on the photochromic coating and its application in the built environment [14][15][16][17][18]. Additionally, among studies of smart windows with photochromic coatings, the effect of such coating on occupants' visual comfort has not been adequately explored.…”

Section: Of 16mentioning

confidence: 99%

The Effect of Smart Colored Windows on Visual Performance of Buildings

2022

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The photochromic coating is a promising smart technology that provides different optical properties in response to daylight variations. The application of photochromic coatings with various colors/shades on window glass is one of the current research approaches for finding better energy saving techniques. The aim of this study was to develop a series of photochromic coatings for window glass and measure the impact of such smart technologies on occupants’ visual comfort. This paper examines the visual performance of building facades that utilize windows with different photochromic-coated glass. The visual performance data of three window types coated with nine different photochromic color shades were considered and compared to determine the best photochromic shades and window types that provide optimum visual metrics for the inside of the building. The results show that compared to no-coating glass, both the Daylight Glare Probability and the Useful Daylight Illuminance could be improved by using multi-color coatings that contain equal or different color proportions for photochromic window glass. From an energy-saving point of view, the results indicate that the windows coated with photochromic materials provide a better alternative to the no-coating window products.

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Electrochromic tungsten oxide films prepared by sputtering: Optimizing cycling durability by judicious choice of deposition parameters

Cited by 28 publications

References 68 publications

Thickness Dependence of WO₃ and NiO_x Thin Films in All‐Solid‐State Complementary Electrochromic Devices

Thickness Dependence of WO₃ and NiO_x Thin Films in All‐Solid‐State Complementary Electrochromic Devices

Charge coloration dynamics of electrochromic amorphous tungsten oxide studied by simultaneous electrochemical and color impedance measurements

The Effect of Smart Colored Windows on Visual Performance of Buildings

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Electrochromic tungsten oxide films prepared by sputtering: Optimizing cycling durability by judicious choice of deposition parameters

Cited by 28 publications

References 68 publications

Thickness Dependence of WO3 and NiOx Thin Films in All‐Solid‐State Complementary Electrochromic Devices

Thickness Dependence of WO3 and NiOx Thin Films in All‐Solid‐State Complementary Electrochromic Devices

Charge coloration dynamics of electrochromic amorphous tungsten oxide studied by simultaneous electrochemical and color impedance measurements

The Effect of Smart Colored Windows on Visual Performance of Buildings

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Product

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Thickness Dependence of WO₃ and NiO_x Thin Films in All‐Solid‐State Complementary Electrochromic Devices

Thickness Dependence of WO₃ and NiO_x Thin Films in All‐Solid‐State Complementary Electrochromic Devices