Enhanced spin lifetime in colloidal quantum dots by growth from singly Mn-doped molecular cluster seeds

Doped colloidal quantum dots (CQDs) are promising spin-photon interfaces, combining excellent optical properties and a substrate-free, nano-positionable platform. Here, we report the synthesis of InP/ZnSeS core-shell CQDs from zinc sulphide based seed clusters containing single Mn(II) ions. The resulting doped CQDs demonstrate photoluminescence quantum yields of up to 70%, a spin-lattice lifetime of 22 ms and a spin coherence lifetime of 2.7 μs, greater than and similar to the best yet reported for Mn-doped CQD systems, respectively. These spin lifetimes were achieved despite the high nuclear spin of InP, demonstrating the effectiveness of the ZnS cluster in shielding the Mn ion from its environment.