Size-Tunable Manganese-Doped Spheroidal CsPbCl 3 Quantum Dots.

Manganese doping has been demonstrated as a versatile tool to tune the emission of CsPbCl 3 nanocrystals (NCs). Although this has been demonstrated in nanocubes and nanoplatelets, strategies for doping Mn 2+ in size-tunable, excitonic CsPbCl 3 quantum dots (QDs) remain absent. In this work, we demonstrate the synthesis of size-tunable spheroidal CsPbCl 3 :Mn 2+ QDs, which can be obtained by a water-hexane interfacial combined anion and cation exchange strategy starting from CsPbBr 3 QDs. Interestingly, the QDs exhibit a fast 0.2 ms Mn 2+ photoluminescence (PL) lifetime and an energy transfer (ET) time of approximately 100 ps from the excitonic state of the QD to the atomic state of the Mn 2+ ion. The size dependence observation of the manganese PL efficiency and the slow ET rate suggest that Mn 2+ mainly gets incorporated at the QD's surface, highlighting the importance of strategies chosen for the incorporation of Mn 2+ into perovskite QDs.