Single-exciton, biexciton, triexciton, and quadraexciton bands were resolved in the microphotoluminescence spectrum of a single $\mathrm{CdTe}/\mathrm{CdSe}$ core-shell colloidal quantum dot, revealing nearly blinking-free behavior. Multiexcitons were generated by a sequential filling of electronic shells with the increase of a continuous-wave excitation power, and their probability was evaluated under steady-state conditions. A partial carriers’ delocalization was determined at the core-shell interface, and an exciton binding energy was estimated by a second-order perturbation theory.

• Received 19 July 2008

DOI:https://doi.org/10.1103/PhysRevLett.102.197401