Ricerc@Sapienza

The employment of X-rays diffraction (XRD) techniques is here proposed for the first time to analyse the structural features of deep eutectic solvents (DESs), i.e. systems with an intrinsically glassy nature, upon variation of the nature of a metal (M) when M, in the generic cationic form M¿n+, is present either in the starting formulation of the DES, or as an extraneous species incorporated by DES after extraction from compounds containing metal cations. The classes of compounds which will be considered as metal cation sources for consideration of extraction with DESs are oxides, sulphides and the rest of the calchogenides, halogens, nitrides, phosphides and arsenides. In this context the presence of M¿n+ with its shell of coordination is expected to introduce structural order at a local level within DESs. As a consequence of that, the resulting profile of diffraction of metal-containing DESs (M-DESs) will display features which make it distinguishable from the diffraction patterns typical of amorphous systems. The structural characterization of the metal-containing DESs will be accompanied by the calculation of the stability of the resulting structures through advanced computational methods. Moreover, the present project proposal intends to determine also the electrical conductivity and the redox properties of M-DESs as function of the temperature with the purpose of evaluating their utilization as viscous, self-standing electrolytes in photoelectrochemical and electrochromic cells. The two types of electrochemical devices here considered require the high optical quality of the materials constituting the various components of the cell. For this reason we consider M-DESs as a particularly palatable choice of gel-like electrolyte because of the favourable combination of optical and conductivity properties. The spectral properties of M-DESs will be evaluated with Raman and UV-vis-NIR spectroscopies.