Fig. 2.

Mechanistic study of the suppressed dissolution approach in ML materials. (a&b) Titration curves (a) and dissolution flux (b) of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$, ZnS:Cu,Al, ZnS:Mn, and CaTiO₃:Pr under constant composition (CC) conditions. (c&d) Titration curves (c) and dissolution flux (d) of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ at different undersaturations as determined by the $\mathrm{p}\mathrm{H}$ of the CC solution. (e-g) SEM images of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ surface before dissolution (e), and after suppressed dissolution at $\mathrm{p}\mathrm{H}=8.8$ (f) and 9.6 (g), respectively. Dissolution steps can be seen in (f&g) after suppressed dissolution. All scale bars represent 1 μm. (h) Histograms showing the step spacing distribution on the ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ surface after suppressed solution at $\mathrm{p}\mathrm{H}=8.8$ and 9.6 in f&g. (i) Experimental data and linear fitting of $ln\{(1-\frac{J}{J_n})[exp(-\frac{\sigma }{6})-1]+1\}$ vs. $-\frac{\sigma }{6r}$ under different undersaturations. (j) The critical lengths $L_c$ of receding steps on the surface of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ under different undersaturations, extracted from the slopes of linear fitting curves in (i). The error bars represent the uncertainty in fitting parameters.