Magneto-optical spectroscopy of charged CdSe nanocrystals

Charged quantum dots provide an important platform for a range of emerging quantum technologies from spin qubits to single phonon sources. Colloidal quantum dots in particular could offer unique advantages for such applications (eg. facile synthesis, manipulation and compatibility with a wide range of environments), especially if stable charged states can be harnessed in these materials. This possibility has been encouraged by recent reports of trion emission from colloidal quantum dots at cryogenic temperatures [1,2] indicating that trion states can be bright with quantum yields approaching unity [1]. However, these reports relied on random ionization to produce the trion state and did not provide any insight into the charging mechanism.