Tailored Synthesis of an Unprecedented Pb–Mn Heterometallic Halide Hybrid with Enhanced Emission

Organic–inorganic lead halide hybrids have attracted extensive interest in solid-state lighting, due to their superior color tunability and low-cost solution processing. However, the relatively low photoluminescence quantum efficiency (PLQE) is a common issue for most bulk lead halide hybrids. Inspired by the intriguing luminescence properties of heterometallic complexes, we rationally developed an unprecedented two-dimensional (2D) Pb–Mn heterometallic halide hybrid, (C₅­H₁₄­N₂)₂­Pb₄­MnCl₁₄ (2), through a precisely tailored synthetic approach based on (C₅H₁₄N₂)₂Pb₅Cl₁₄ (1). Intriguingly, 2 features a unique 2D heterometallic halide layer configuration, in which the strong quantum confinement facilitates efficient energy transfer from bound excitons to d-states of Mn²⁺, resulting in highly sensitized Mn²⁺emission. The PLQE of 2 is up to 32%, considerably higher than that of pristine 1 (less than 1%). Moreover, 2 presents significant environmental and thermal stability, benefiting from its cluster feature. To our best knowledge, this is the first example of construction of a Pb–Mn heterometallic halide hybrid with bulk highly efficient red emission. This work provides a way to enhance the PLQE of lead halide hybrids via sensitization in rationally designed heterometallic halide hybrids.