Studies on the electronic and vibrational states of colloidal CdSe/ZnS quantum dots under high pressures

The electronic and vibrational states of colloidal core/shell CdSe/ZnS quantum dots are studied at room temperature by using high pressure optical measurements. Pressure-induced quadratic variations of lattice constants can be observed clearly from both photoluminescence (PL) and Raman spectra up to ∼7 GPa. This quadratic relationship is consistent with the theoretical prediction. The pressure coefficients of linear and quadratic terms are 32 meV GPa−1, −1 meV GPa−2 for PL and 4.2 cm−1 GPa−1, −0.1 cm−1 GPa−2 for Raman measurements, respectively.