Solid-State Synthesis and Optical Studies of Water-Stable Pb2+-Doped Mn2+ Complexes

The limited Mn2+ doping that occurs in lead halide perovskites has been widely described, while the Pb2+ doping that occurs in Mn2+ halide perovskites has not been studied well. Generally, a large amount of doping of Mn2+ in lead halide perovskite degrades the perovskite structure; eventually, high orange luminescence of Mn2+ dopant has not been achieved. In our present study, we followed a reverse strategy, i.e., Pb2+ doping in Mn2+ halide perovskites, to increase the amount of Mn2+ in halide perovskites through the high-energy ball milling method. This strategy yields bright-fluorescence orange light-emitting Mn2+-doped perovskite with a Mn/Pb ratio of 95%, which is the highest among Mn2+-doped perovskites. Zero-dimensional (0D) Mn2+ perovskites and two-dimensional (2D) Pb2+-doped Mn2+-based perovskites were successfully synthesized and characterized. During the mechanochemical engineering, Pb2+ ions partially occupy the site of Mn2+ ions and act as a luminescence activator. Mn2+-based 2D perovskites with the proper amounts of Pb2+ ions as dopant ions and phenylethylammonium (PEA+) as dielectric organic cations show enhanced stability in water. The dual-emissive properties of these 2D-Pb2+-doped Mn2+-based perovskites were also investigated by using single-particle imaging fluorescence. We believe that these findings will pave the way for designing eco-friendly dimension and bandgap tunable layered perovskites.