The recrystallization simulation results can be seen in Figure 2 B for different acid concentrations. The recrystallization trend is consistent with the densification and grain growth trends observed in experiments. According to our simulations, as soon as the solvent meets the ZnO surface, a liquid/solid interface is formed with three layers (Figure S7): 1) a hydroxide layer due to dissociation of water molecules on the surface, 2) a structured water layer due to the interactions between the water molecules and the hydroxide layer, and 3) a bulk solvent layer including dissolved Zn+2 ions. Due to the amphoteric behavior of the ZnO surface, the hydroxide layer is composed of bridging and terminal hydroxyl groups.