Lanthanide doping enabled multimodal luminescence in layered lead-free double perovskite Cs4MnBi2Cl12†
Abstract
The incorporation of lanthanide ions (Ln3+) has been shown to be an effective strategy to tune the luminescence properties in lead-free halide double perovskites. However, most Ln3+-doped double perovskites exhibit a low luminescence efficiency and a high excitation energy and/or require doping with multiple ions which result in complex compositions. Herein, we demonstrate that the Ln3+ doping (Ln = Yb, Er, Nd) in the layered double perovskite Cs4MnBi2Cl12 enables multimodal luminescence, that is, the orange-red emission from the d–d transition of Mn2+, the efficient ultraviolet light excited near-infrared (NIR) emissions of Ln3+ and the upconversion emissions in both Yb- and Yb/Er-doped systems. In addition, the NIR emissions of Ln3+ can also be excited by blue and green light benefiting from the energy transfer from Mn2+ to Ln3+. Finally, taking advantage of the multimodal luminescence in the Ln3+-doped Cs4MnBi2Cl12 phosphor, a preliminary anti-counterfeiting application is demonstrated. We highlight that the particular chemical composition (comprising Bi3+ and Mn2+) and the sandwich-type Bi–Mn–Bi layered crystal structure facilitate the light absorption and the energy transfer from Bi3+ to Ln3+ and Mn2+ to Ln3+, demonstrating the importance of the rational selection and design of double perovskite host materials for Ln3+ doping.