Extracting the homogeneous and inhomogeneous linewidths of colloidal quantum dots from the excitation-emission matrix

The excitation-emission matrix (EEM) of colloidal quantum dots implicitly contains information about the inhomogeneous broadening and the homogeneous linewidths of the emission spectrum and of the excitonic peak in the photoluminescence excitation spectrum. Here, the characteristic features by which this information is manifested in the EEM contour plot are identified. In the Gaussian approximation, the contour lines are ellipses, whose parameters can be used to calculate the homogeneous linewidths and the inhomogeneous broadening. The method is illustrated on the core/shell InP/ZnS nanocrystals.