Density dependence of photoluminescence lifetime of CdSe/ZnS core-shell colloidal quantum dots

We measured the density dependence of both the photoluminescence (PL) spectrum and the PL lifetime of CdSe/ZnS core-shell colloidal quantum dots (QDs) from 0.01 to 10.0 nmol/ml at room temperature. We found that the PL lifetime increased drastically while the PL spectrum changed slightly with an increase in the density of the QDs. The density dependence of the PL lifetime is explained using the imprisonment of resonance radiation model, which has been discussed in atomic systems. (C) 2011 American Institute of Physics. [doi:10.1063/1.3642074]