Figure 3
PL spectra of Zn/Al \(({{\rm{NO}}}_{3}^{-})\)-LDH nanoplatelets grown on Al foils showing the emergence of dehydration induced UV photoluminescence features and their reproducible quenching in the hydrated sample. (a) Room temperature PL spectra collected over a ∼5 minutes long dehydration process in vacuum (1000-10−3 mBar) followed by a 5 h re-hydration in ambient humid air, showing the reversible off-on-off process relevant to the emergence of the intense UV PL features. (b) PL spectra collected during a dehydration process induced by thermal annealing (300–400 K) in air. Sketches of desorption (dehydration) and adsorption (hydration) of adsorbates from/on LDH surfaces are also displayed. (c) PL spectra collected during the room temperature dehydration in vacuum and re-hydration in humid air reported in (a), plotted in a logarithmic scale. (d) Room temperature PL spectra collected in humid air at atmospheric pressure and in vacuum from respectively hydrated (red line) and dehydrated (black line) LDH films. In the inset a higher resolution spectrum (600 lines mm−1 grating) of the PL by a dehydrated LDH sample in vacuum is shown as a function of photon energy. Blue lines represent the individual Gauss-Lorentzian peaks and the resulting best fit of the experimental data.
