Solid-State Synthesis and Optical Studies of Water-Stable Pb 2+ -Doped Mn 2+ Complexes.

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