Mn2+ as a Radial Pressure Gauge in Colloidal Core/Shell Nanocrystals

The fluorescence of Mn²⁺ doped in the shell of CdS/ZnS core/shell nanocrystals at radially controlled position is used as a local probe of pressure in the nanocrystal shell. The redshift of the fluorescence with increasing shell thickness indicates a pressure of more than 4 GPa for 7.5 monolayers of ZnS. The radial dependence and magnitude of the pressure derived from the Mn²⁺ fluorescence shift are in good agreement with the spherically symmetric elastic continuum model and the 7% misfit between the core and the epitaxial shell.