Modulating Room‐Temperature Phosphorescence Emission of Piperonylamine‐Based Organic Inorganic Hybrids Via Metallic Halide

Abstract Zero‐dimensional (0D) organic metal halides (OIMHs) with room‐temperature phosphorescent (RTP) properties have aroused great research enthusiasm due to their long lifetime of triplet excitons and environment stability. Despite extensive research on the RTP emission of OIMHs in different metal ions, there has been limited reporting on the excellent luminescent properties of triplet excitons originating from organic ligands via metallic halide modulation, although they have intriguing luminescent properties. Here, piperonylamine (piperA) is taken as organic cations and two new OIMHs are synthesized, (piperA)₃ClSbCl₅ and (piperA)₃ClInCl₅·H₂O, with differently enhanced RTP emission compared with (piperA)Cl ligand. Structural and photophysical studies reveal that the increased RTP emission is due to the enhanced π–π stackings between the adjacent piperA ligands in (piperA)₃ClSbCl₅ and (piperA)₃ClInCl₅·H₂O. Mechanism analysis demonstrates that the diverse stacking arrangements of crystal structure result in distinct energy transfer pathways, potentially accounting for the varying degrees of enhancement in phosphorescent lifetime. This work developed a method for regulating the RTP of organic ligands in OIMH using metal ions to achieve long RTP emission, providing a new approach for designing ultra‐long RTP emission materials.