PRODUCTION OF NANOCOMPOSITE WO₃/rGO ELECTROCHROMIC FILMS BY THE METHOD OF SPRAY-PYROLYSIS ON GLASS ITO SUBSTRATES

Modern materials science is developing towards the creation of functional materials with adjustable properties and parameters. The materials with electrically controlled optical properties, so-called electrochromic films, take the special place in the hierarchy of materials with adjustable parameters. The electrochromic films become widely used when creating a new generation of devices, both in various fields of electronics and in the field of renewable energy. From the practical point of view, one of the possible ways of improving technical characteristics of electrochromic films is their modification by carbon nanomaterials, in particular, by graphene oxide (GO) and reduced graphene oxide (rGO). The use of GO and rGO as a modifier for the electrochromic materials is caused by some unique features, namely: low sensitivity to ultraviolet radiation, chemical inertness, high specific surface area, the ability to change the charge state, and the increased electrical conductivity of rGO. To produce the electrochromic films, the authors used the spray-pyrolysis method. This method allows for obtaining the electrochromic films based on nanoscale tungsten trioxide (WO₃) modified by rGO. The authors studied the electrochemical characteristics of electrochromic films and the influence of rGO on the performance of the electrochromic films. The WO₃/rGO electrochromic films were reversibly colored in violet at the voltage of -2.1 V, as well as increased light transmission coefficient at the positive voltage of +2 V. During the research, the authors studied spectral properties of the produced nanocomposite WO₃/rGO electrochromic films at various values of electrical potential and evaluated their stable cycling within the range of voltage from -0.7 to 1 V for the three-electrode system. The study identified that the controllable activation of WO₃/rGO electrochromic films related to the increase in light transmission is in the voltage range from -1.6 V to -2.2 V, and the inverse effect is peculiar for the range from 0 to +2 V.

graphene oxide, electrochromic films, tungsten trioxide, optical spectroscopy