Supplement Number 1

Supplementary material 1 for the following details: (1) Preparation and characterization of cluster QDs. (2) Preparation and characterization of single QDs. (3) Calculate the number of photons absorbed per pulse by single QDs. (4),(5) Representative fluorescence intermittency and fluorescence lifetime trajectories of single red QDs without and with the presence of green QDs under 403 nm laser excitation. (6) Representative fluorescence intermittency of single red QDs in same red-green QDs films excited by different laser. (7) Calculation of dark state duration ratio.