A last important point to address is the scalability of the synthesis and how the present findings from screening studies performed in low volumes translate at larger scale. To assess how scalable the presented results obtained with less than 3 mL transfer to larger volumes, we performed a range of experiments with a total volume of 100 mL (ca. 10 mg of Au NPs assuming a 100% conversion). The scaling was performed with 20 v.% ethanol and a Base/Au molar ratio of 4 for a synthesis time of 2 hours. The results are reported in Figure and section S12. Figure . λspr values retrieved from UV-vis characterization for samples prepared without or with N2 purge and for different light environments, bases and volumes, as indicated. The reaction mixtures consisted of 0.5 mM HAuCl4, a Base/Au molar ratio of 4 in 20 v.% ethanol for a total volume of 3 mL in glass vials or 100 mL in Pyrex® bottles, as indicated. The reaction was performed for 2 hours under the indicated light conditions and the sample were then left at RT and ambient light for a day. Each data point is the result of at least x3 experiments for experiment performed in 3 mL (plain dataset), except for the Dark condition and N 2 using LiOH as base where x1 experiment was performed. The dataset with 100 mL results from x1 experiment for each condition.