Structural Flexibility Driven Crystal‐to‐Glass Transition and Long‐Afterglow in Mechanochemically Synthesized Zn(II) Hybrids

ABSTRACT

Achieving controllable vitrification in organic‐inorganic metal halides (OIMHs) without luminescence quenching remains a challenge due to rigid structural constraints. Herein, we exploit the structural flexibility inherent in 0D Zn(II) hybrids to develop a mechanochemical strategy for coordination‐engineered long‐afterglow materials. By simply modulating liquid‐assisted grinding (LAG) agents, we achieve precise interconversion between halide‐coordinated [ZnX ₄ ] ²⁻ and coordination‐type [ZnNX ₃ ] ²⁻ geometries. Crucially, this flexible coordination environment facilitates a crystal‐to‐glass transition ( T _g = 51.1°C –65.1°C) while preserving luminescent integrity. The resulting materials exhibit tunable room‐temperature phosphorescence (3.6–11.7 ms), with ( IMP )ZnCl ₃ showing a persistent yellow afterglow. Density functional theory (DFT) calculations reveal that halogen substitution and coordination geometry synergistically regulate charge‐transfer processes. This work establishes a structure‐flexibility‐luminescence relationship, enabling dynamic anti‐counterfeiting systems based on time‐resolved optical logic.