## 3 Results
### Characterization of Physical Properties
#### 3.1.4 UV-Vis-NIR Spectrophotometry and Optical Properties  
The advancement of mobile device technology demands comprehensive insight into the optical properties of protective layers, pointing to the importance of oxide selection and processing conditions in advanced display technologies. Silicon dioxide has been highlighted for its potential to maintain cell selectivity, especially regarding the stability of PEG films and suppressing cell adhesion [50]. Incorporating metals like silver into oxides to enhance their optical properties is an emerging research area [51; 52; 53]. When applied to protective films, Ag-doped semi-transparent layers play an important role in ensuring the optimal performance of device displays, especially regarding clarity and durability. The optical properties of TiO\({}_{2}\)+Ag and SiO\({}_{2}\)+Ag coatings were evaluated by spectrophotometric measurements, Figure 5, emphasizing their significance in designing and applying layers for mobile device displays. Initial evaluations indicated a pronounced transparency for the SiO\({}_{2}\) layers in the visible range, substantially higher (\(\sim\)20%) than the one corresponding to the TiO\({}_{2}\) layer without O\({}_{2}\) addition. In contrast, when the layers were synthesized using a stoichiometric  
Figure 4: (**a**) EDX spectra of the coatings deposited on polymer support in 3 different processes: SiO\({}_{2}\) and Ag targets in Ar atmosphere, TiO\({}_{2}\) and Ag targets in Ar atmosphere and TiO\({}_{2}\) and Ag targets in Ar+O\({}_{2}\) atmosphere, with a concentration of 2.5% O\({}_{2}\) from the total gas flow, and (**b**) the variation of the ratios Ag to Si(Ti) and Ag to O, respectively, and of Ag concentration. TiO\({}_{2}\) target in a reactive gas mixture of Ar and O\({}_{2}\), TiO\({}_{2}\) layers exhibited a comparable transparency to SiO\({}_{2}\) layers. Further spectral analysis did not identify a unique absorption peak intrinsically linked to the surface plasmonic resonance phenomenon, attributable to the Ag nanoparticles. This suggests a fine distribution of silver within the oxide structure, preventing the formation of metallic nanoclusters. These results support our initial hypothesis drawn from X-Ray Diffraction analysis, further underlining the conclusion that silver remains finely dispersed within the oxide matrix rather than forming distinct crystalline clusters [47]. This finding also aligns with previous studies that have demonstrated the attenuation or absence of the Ag (111) diffraction peak in Ag-doped amorphous TiO\({}_{2}\) or SiO\({}_{2}\) matrices due to Ag incorporation at the atomic level or in sub-nanometric forms [54]. Our observations, where the absence of a characteristic Ag diffraction peak in Ag+TiO\({}_{2}\)+O\({}_{2}\) coatings indicates that the deposition conditions mostly imply Ag dispersion rather than aggregation, provide further consistency with these previous studies. In general, the size and shape of Ag nanoparticles also influence the optical properties, leading to an oxidation-driven stabilization of Ag species within the amorphous matrix [55]. This process can prevent Ag atoms from diffusing and clustering into larger particles, which XRD analyses would otherwise confirm. Such effects have been observed in reactive sputtering processes, where oxygen-rich conditions promote finer Ag distribution and suppress long-range crystallinity [56]. Moreover, the structural disorder in amorphous oxides enhances atomic mobility, influencing metal dispersion. Previous studies showed that the lack of distinct IR spectral features associated with silver in Ag-doped TiO\({}_{2}\) suggests that silver atoms are incorporated within the TiO\({}_{2}\) matrix, likely occupying interstitial sites rather than forming separate metallic clusters [57].