Electrochromic switching of tungsten oxide films grown by reactive ion-beam sputter deposition

Abstract

Chromogenic thin films are crucial building blocks in smart windows to modulate the flux of visible light and heat radiation into buildings. Electrochromic materials such as tungsten oxide are well established in those devices. Sputter deposition offers a well-suited method for the production of such layers, which can also be used on an industrial scale. Tungsten oxide films were prepared by means of reactive ion-beam sputter deposition. The choice of distinct gas mixtures as well as the growth temperature during the sputtering process allows to tune the properties of the resulting layers. Especially, the variation in the growth temperatures was found to have an impact on the structure of the resulting samples and, as a consequence, on their optical and electrochemical properties. By specific choice of the reactive gas, the deposition of colorless transparent as well as blue films of different composition is possible. The optical transmittance in the visible spectral range was up to 75% for as-deposited oxygen-rich layers. Additionally, hydrogen-doped tungsten oxide samples were grown. Superior electrochromic switching was observed for H$$^{+}$$ + -doped layers, probably by some kind of preconditioning. This resulted in a value for the standardized optical coloration efficiency of 26.5 cm$$^{2}$$ 2 /C.

Enhanced dual-band modulation of visible and near-infrared light transmittance in electrochromic composite films based on Preyssler-type polyoxometalates and W18O49

“…The CE can be calculated from eqn (3) and (4): 33 6d, and this proved that the composite membrane has good coloration efficiency. 22,23,[34][35][36] The modulation of sunlight and solar heat of the EC device was tested in Fig. 5g and h.…”

Thermochromic Energy Efficient Windows: Fundamentals, Recent Advances, and Perspectives

“…Low-E materials of Pt, AZO, and sliver were deposited on VO 2 to enhance the thermal insulation properties; however, significant deteriorations on T lum and Δ T sol were observed accompanied by the lowered emissivity, owing to the strong plasm resonance absorption for the Low-E materials at visible and near-infrared range. Other solar modulation smart windows, e.g., electrochromic , and gasochromic windows, also indicate this inferior influence.…”

Assessing the Electronic Structure of TaVOx and Its Electrochromic Performance in Combination with LiPSON

“…Voltage reversal and the corresponding deintercalation of the ions restore the initial state. Tungsten oxide is a well-established electrochromic material and has already been mentioned as early as 1969 by Deb. , It exhibits strong coloration due to ion intercalation, i.e., cathodic electrochromism. − Electrochromic devices are completed by an ion storage layer, which needs to fulfill two major requirements. First, a suitable storage capacity has to be available for the ions involved in the electrochromic switching process.…”