Unveiling Dopant‐Induced Ultrafast Exciton Dynamics in Mn/Yb Codoped Perovskite Nanocrystals

Abstract

Perovskite nanocrystals (NCs) with intentionally introduced Mn2+/Yb3+ activators enable tunable emissions covering UV‐orange‐NIR spectral range. However, the exact microscopic energy transfer mechanisms in this system remain unknown. Herein, Mn/Yb codoped CsPbCl3 perovskite NCs with triple emissions originated from exciton recombination of host, 3d–3d transition of Mn2+ and 4f–4f transition of Yb3+ are prepared. Femtosecond resolution transient absorption spectra performed on the pristine CsPbCl3, Mn‐doped, Yb‐doped and Mn/Yb codoped samples clarify efficient and simultaneous energy transfer (ET) from excitons to Mn2+ and Yb3+ dopants. It is testified the sensitizations of dopants mainly result from the trapped hole, taking 285 ps for Mn2+ and 17 ps for Yb3+ respectively, which make less trapped hole recombine with de‐localized carriers. Importantly, energy transfer processes from host to Mn2+ and Yb3+ activators emerge as competition, and the ET probability of exciton‐to‐Mn2+ is higher than that of exciton‐to‐Yb3+. Finally, control experiments further prove that tunable Mn2+ orange emission and Yb3+ NIR emission are achievable via elaborate adjustment of the dopant concentrations.

Near-infrared two-photon excited photoluminescence from Yb3+-doped CsPbClxBr3−x perovskite nanocrystals embedded into amphiphilic silica microspheres

“…S5c-e †), which is again consistent with previous reports on Yb 3+ -doped perovskites. 41,46,47 The shifts are more pronounced for Pb and Cl elements, indicating a stronger Pb-Cl interaction resulting from the partial replacement of Pb 2+ ions with Yb 3+ ions and lattice contraction. 48,49 Optical properties of the Yb 3+ :CsPbCl 3 NCs are depicted in Fig.…”