Efficient External Energy Transfer from Mn-Doped Perovskite Nanocrystals.

Doping with a transition metal is an effective way to tune the optical properties of semiconductor nanocrystals (NCs). The excitation of transition-metal dopants in NCs is through an internal energy transfer from a host exciton, by which the short-lived exciton energy can be "stored" at the dopant for a significantly longer lifetime. Herein, using Mn-doped CsPbCl perovskite NCs as an example, we report that the long-lived excited state at Mn dopants can be efficiently extracted from the NCs through an external energy transfer (EET) to rhodamine B (RhB) molecules adsorbed on the NC surface. The EET process leads to a delayed RhB emission. The EET rate is found to increase from 0.16 to 1.42 ms as the number of RhB molecules adsorbed per NC increases from 1 to 8.9, leading to energy extraction efficiency up to 71%. This work suggests the potential of Mn-doped perovskite NCs for applications in photon energy conversion and biological imaging.