“Smart” windows are one from a broad range of “smart” devices. “Smart” windows can change optical state from transparent to non-transparent through a row of partially transparent states. They can be used for decreasing electricity consumption, lower consumption in peak periods and comfort increasing in buildings.
Ni(OH)2 is well-known promising electrochromic material for elements of a “Smart” window. It can be deposited on conductive substrates (e.g. FTO, ITO) from Ni(NO3)2 solutions by means of the electrochemical method. The electro-chemical method is simple, inexpensive and not requires complex equipment. The limitation of this method is a low current distribution on the high-resistance substrate during deposition process caused by the low-conductive substrate. Also, the bleaching-colorization process can be non-uniform and that is caused by a high-resistance substrate.
In order to increase current distribution on the high-resistance substrate, the deposition on its surface of the silver grid was performed.
Fig. 1 − Cyclic voltammetry curves for: a – FTO glass covered with Ni(OH)2 film; b – FTO glass covered with Ag grid and Ni(OH)2 film.
The silver grid was deposited by the aerosol printing method . The size of the grid was 2x2 cm with inner square 1x1 cm – Fig. 3a, b. Further, Ni(OH)2 deposition on FTO glass & FTO glass with Ag grid was performed according to .
Fig. 2 − Colorization-bleaching curves for: a – FTO glass covered with Ni(OH)2 film; b – FTO glass covered with Ag grid and Ni(OH)2 film.
Fig. 3 − Photo of electrodes in the colored state: a, b – FTO glass covered with Ag grid and Ni(OH)2 film; b, c – FTO glass covered with Ni(OH)2 film.
In order to define performance Ni(OH)2 films on different substrates cyclic voltammetry with simultaneous recording of optical dependencies were done – Fig. 1-3. All CVs and colorization-bleaching curves showed sharp differences. As such, Ni(OH)2 film deposited on FTO glass with Ag grid showed additional peaks on the CV and higher bleaching velocity. Also, the colorization of the electrode on FTO glass with Ag grid was more uniform – Fig. 3.
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