Figure 2.

Thermally activated PL decay at zero magnetic field for the InP/ZnSe core/shell QDs (sample 1). (a) PL decay measured at the PL peak maximum (which depends on temperature; see Figure S1b), at various temperatures from 4 K (blue) to 200 K (dark red). (b) Plot of the lifetime of the long component of the decay curves versus the temperature. The fitting (red line) is based on the thermal-occupation model (eq 1) with a thermal activation energy ΔE_T between the dark state |d⟩ and an optically active state |d,1⟩ of 5.5 meV. Inset: Schematic representation of the three-level scheme, with the dark state and thermally activated state with a higher oscillator strength.