## Results
### Characterization of the Grown WO\({}_{3}\) Films  
XRD analysis and Raman spectroscopy (Figure 3) were employed to study the structure and phase composition of the obtained WO\({}_{3}\) film on glass. The diffractogram shown in Figure 3a reveals no discernible crystalline phases--the only feature is a wide halo in 13-38 deg, which is characteristic of the glass substrate. This indicates that the grown film is X-ray amorphous, due to being either too highly dispersed or amorphous in nature. Further study with Raman spectroscopy (Figure 3b) revealed that all visible bands are also characteristic of glass. Namely, the bands with maxima at 1183, 1097, and 954 cm\({}^{-1}\) can be attributed to the Q\({}^{4}\), Q\({}^{3}\), and Q\({}^{2}\) modes of Si-O stretching vibrations, the wide and low-intensity band around 794 cm\({}^{-1}\) is related to Si vibration in its tetrahedral oxygen cell, and bands at lower wave numbers are caused by Si-O-Si bending vibration modes, including from the rings of three Si around 570-600 cm\({}^{-1}\)[51; 52; 53; 54; 55]. Many of the band's characteristics of W-O-W and O-W-O in various modifications of WO\({}_{3}\), such as those with maxima around 800-820 cm\({}^{-1}\), 650 cm\({}^{-1}\), and 320-330 cm\({}^{-1}\), overlap with glass bands. However, a rather intense band around 690-715 cm\({}^{-1}\) is usually observed for WO\({}_{3}\), and an overlap with glass bands would be minimal in this region [56; 57]. In our case, no band can be observed with certainty in this region. Thus, the grown oxide film is most likely too highly dispersed and thin to be observed by Raman spectroscopy. Combined with the XRD analysis results, it follows that the WO\({}_{3}\) film seems to be very highly dispersed, which should result in a very developed surface with a large specific area. This, in turn, should positively impact the electrochromic properties of the material since associated processes occur at the oxide's surface. To further characterize the obtained films, their transmittance spectra were recorded in the visible range (Figure 4). It can be seen that the WO\({}_{3}\) film on the glass substrate has a very low transparency--only 53% transmittance at a wavelength of 600 nm. Subtracting the transmittance spectrum of the original glass substrate shows that the contribution to the absorption directly from the oxide film is about 51% (at 430 nm). The WO\({}_{3}\) film on the glass/ITO substrate, despite the fact that it was deposited in three cycles, contributes significantly less to the absorption of the corresponding sample--only up to 21.5% (at 460 nm). Such a difference in transparency between the two films formed on the surfaces of different substrates can partially be explained by the antireflection effect in the case of the glass/ITO substrate. Figure 2: UV spectra of the complex solution during its sequential hydrothermal treatment at different temperatures (**a**); dependence of the degree of destructive substitution of chelate ligands (\(\alpha\)) for alkoxy fragments during sequential hydrothermal treatment of the alcohol solution of the complex [WO\({}_{2}\)(C\({}_{5}\)H\({}_{7}\)O\({}_{2}\))\({}_{2}\)] (**b**). Then, the WO\({}_{3}\) coating grown on a glass substrate was examined using SEM. The microphotographs (Figure 5) show that the oxide film is formed from several microstructural units uniformly occurring on the surface of the sample. Firstly, spherical formations with a diameter of 400 to 550 nm consisting of smaller nanoparticles 15-55 nm in size can be distinguished (Figure 5). Second, elongated ridges of varying lengths, mostly less than 1 \(\upmu\)m, and widths from 100 to 400 nm can be distinguished. Some of these ridges are formed from two or more units which were originally submicron spheres. Finally, nanoparticles of rounded or slightly elongated shape can be distinguished--the rounded ones are generally 50-55 nm in diameter, while the more elongated ones are 80-140 nm in length.