Figure 8.

UV-vis absorption spectra (A) and normalized spectra (B) of freshly prepared Ag–NP samples (dotted lines) and samples stored for 1 month in the dark at ambient temperature (solid lines).

Notes: Samples were prepared by 532 nm LASiS (60 mJ/pulse; 10 ns) in an aqueous starch solution (1% wt) at different laser repetition rates (ablation time = 15 minutes; λ_max = 403 nm). (A) An increase in absorption of the long wavelength tail can be clearly noticed for all repetition rates, as well as a clear pool of particles with a λ_{max-40 Hz} = 723 nm at 40 Hz repetition rate (black arrow). Furthermore, a characteristic change below 400 nm occurs. The changes in the enclosed areas were calculated via integration and subtracting spectra from 30-day-old samples from newly prepared solutions (AUC). The insert in (B) shows no significant red-shift with increasing storage (spectra normalized to λ_{max-40 Hz} for comparison reasons).

Abbreviations: AUC, area under the curve; LASiS, laser ablation synthesis in solution.