High-Efficiency Luminescence of Mn2+-Doped Two-Dimensional Hybrid Metal Halides and X-Ray Detection

Mn²⁺ doping in metal halide perovskites enables host-to-dopant energy transfer, creating new emission pathways for optoelectronic applications. However, achieving high-efficiency luminescence in 2D systems remains challenging. We synthesized Mn²⁺-doped 2D PEA₂CdCl₄ via the hydrothermal method, characterizing its properties through PL spectroscopy, quantum yield measurements, and DFT calculations. Flexible films were fabricated using PDMS and PMMA matrices. The 15% Mn²⁺-doped crystal showed orange-red emission with 90.85% PLQY, attributed to efficient host-to-Mn²⁺ energy transfer and ⁴T₁→⁶A₁ transition. Prototype LEDs exhibited stable emission, while PDMS films demonstrated flexibility and PMMA films showed excellent X-ray imaging capability. This work demonstrates Mn²⁺ doping as an effective strategy to enhance luminescence in 2D perovskites, with potential applications in flexible optoelectronics and X-ray scintillators.