Photon-correlation Fourier spectroscopy of the trion fluorescence in thick-shell CdSe/CdS nanocrystals

Abstract : The emission spectrum of the trion state in very thick shell CdSe/CdS nanocrystals is characterized at 4 K by photon correlation Fourier spectroscopy. A value of 50 μeV for the width of the zero phonon line is measured. The absence of blinking and the high photostability of these emitters offer the possibility to investigate the dynamics of the emission spectrum at a time scale as short as 250 ns. We show that the high value of the linewidth (50 μeV) is not due to spectral diffusion induced by the close environment of the emitter at time scales larger than 250 ns. The broadening is attributed to the additional third carrier when compared to the monoexcitonic state.