NIR‐to‐Vis Emission Conversion Enabled in Zero‐Dimensional Metal Halides Under High Pressure

ABSTRACT Zero‐dimensional (0D) hybrid metal halides (HMHs) are an emerging class of multifunctional emitters with ultra‐broad photoluminescence (PL) coverage. However, the key structural parameters governing their emission profile across the visible (Vis) and near‐infrared (NIR) spectral regions remain elusive. Herein, high pressure is applied to manipulate the PL coverage of photoactive [Sb 2 Cl 8 ] 2− dimers, achieving a remarkable switching from NIR to Vis PL regions. Combined optical analyses of (C 13 H 22 N) 2 Sb 2 Cl 8 reveal that intra‐pyramidal distortions promote efficient self‐trapped exciton (STE) recombination from singlet states, whereas restricted distortions favor higher‐energy triplet STE emission. Guided by this mechanism, a derivative with a smaller cation, (C 10 H 16 N) 2 Sb 2 Cl 8 , is designed to enhance structural distortion. Sufficient structural distortions in both intra‐ and inter‐pyramidal architectures lead to intense, eye‐visible orange‐yellow luminescence exclusively from singlet STEs under pressure. This study elucidates the emission mechanisms of 0D antimony halides and establishes structural distortion engineering as a strategy for tunable NIR‐Vis luminescence.