Fig. 3

XAS spectra of neutral and oxidized dyes in presence of chloride. Chlorine K-edge X-ray absorption spectroscopy (XAS) spectra recorded on TiO2 substrates stained with Dye-I and Dye-I+ in the presence of 100 mM acetonitrile solution of tetrabutylammonium chloride. The pre-edge feature at ca. 2818 eV is indicative of a halogen bonding interaction where charge is transferred from chloride to the σ*XB