Fig. 1.

Synthesis of multicolor mechanoluminescent colloids via a bioinspired approach. (a) SEM images of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ (i), ZnS:Cu,Al (ii), ZnS:Mn (iii), and CaTiO₃:Pr (iv) bulk ML materials after solid-state reactions. (b) TEM images of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ (i), ZnS:Cu,Al (ii), ZnS:Mn (iii), and CaTiO₃:Pr (iv) ML colloidals produced by the suppressed dissolution approach. The insets in a&b are luminescence images of the corresponding ML materials in an aqueous solution. The scale bars represent 50 μm in a and 200 nm in b. (c) Histograms showing the size distributions of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ (i), ZnS:Cu,Al (ii), ZnS:Mn (iii), and CaTiO₃:Pr (iv) colloidals. (d&e) Brightfield (top) and luminescence (bottom) images of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ colloids in water (d) and FBS (e). (f) Luminescence intensity of ${\mathrm{S}\mathrm{r}}_2{\mathrm{M}\mathrm{g}\mathrm{S}\mathrm{i}}_2{\mathrm{O}}_7:\mathrm{E}\mathrm{u},\mathrm{D}\mathrm{y}$ colloids in water and FBS over the course of 1 week.