Based on the new insights provided, a preliminary optimization of the time of exposure to controlled light is proposed in section S12. A controlled light environment is key mainly in the first minutes of the reactions which opens opportunities to develop even greener syntheses. This observation is in line with the fast kinetics of the reaction in the initial stages (see section S11). We previously showed that using N2 could lead to smaller NPs, however this approach is relatively complex and more expensive. Nevertheless, it is possible to combine the effect of N2 and controlled light environment to develop synthetic strategies leading to even smaller size NPs as illustrated in Figure and detailed in section 12.