Synthesis and Optical Properties of Mn2+-Doped Amino Lead Halide Molecular Clusters Assisted by Chloride Ion

Mn2+-doped amino lead halide molecular clusters (MCs) are synthesized using amine (e.g., n-octylamine, or butylamine) as passivating ligand and MnX2 (X = Cl or Br) as the Mn2+ doping source at room temperature. Their optical properties are investigated with UV–visible absorption, photoluminescence (PL), and PL excitation spectroscopy. The Mn2+ precursor plays a vital role in the synthesis of Mn2+-doped MCs. MnCl2 seems to facilitate the incorporation of Mn. The MnCl2 doping causes electronic absorption blue shift and leads to a spin-forbidden 4T1 → 6A1 Mn d-electron emission. With the help of time-resolved PL, Fourier transform infrared, and electron paramagnetic resonance results, a model is proposed to explain the formation mechanism. We suggest that Mn2+ doping replaces Pb2+ is assisted by Cl– ions that replace Br– ions. This study demonstrates the possibility of doping MCs and has important implications in gaining new fundamental insight into the growth mechanisms of perovskite nanostructures.