Concurrent Energy- and Electron-Transfer Dynamics in Photoexcited Mn-Doped CsPbBr3 Perovskite Nanoplatelet Architecture.

Mn-doped perovskites have already been widely explored in the context of interesting optical, electronic, and magnetic properties. Such fascinating traits showcased by them explain the huge augmentation in the device efficiency, directing their widespread application in the field of solar cells, energy- harvesting sectors, and light-emitting diodes. However, the underlying photophysics governing the overall charge carrier dynamics in Mn-doped CsPbBr3 nanoplatelets (NPLs) has never been discussed and therefore demands an in-depth investigation. Herein, fluorescence up-conversion and femtosecond transient absorption (TA) spectroscopy are employed for gaining a comprehensive understanding of the excited-state dynamics and the fundamental energy/charge-transfer processes for two-dimensional CsPbBr3 nanoplatelets (NPLs) and their Mn-doped counterparts. The up-conversion measurement clearly suggests the possibility of energy-transfer pathways in the Mn-doped CsPbBr3 NPLs. Interestingly, strong indication of charge transfer (CT) in Mn-doped CsPbBr3 NPLs was unambiguously established by an ultrafast TA approach. Our investigation clearly suggests that both the probable processes viz. the ultrafast energy and electron transfers noticeable in the Mn2+-doped CsPbBr3 NPLs are utterly competitive and rapid owing to the highly confined nature of the two-dimensional NPLs. This extensive probing of concurrent charge/energy-transfer processes may pave help clarify unresolved anomalies in Mn-doped perovskites, which may prove advantageous for a wide range of practical applicability.