Unveiling the Structure-Luminescence-Stability relationship in 5s2-Based Antimony halides toward High-Performance emitters

Abstract

Emerging low-dimensional metal halides have attracted enormous research interests due to their prominent photoluminescence (PL) properties and extensive application potentials. However, the systematic discussion on the structure-luminescence-stability relationship is still lacking. Herein, a series of novel lead-free metal halides are developed to unveil the underlying relationship. The as-synthesized (C6H5NH3)6SbCl9·H2O single crystal is structurally unstable that would spontaneously transform into (C6H5NH3)3ClSbCl5·H2O in the mother liquor, due to the strong antibonding Sb-5s2 lone pair with a spherical distribution in highly symmetrical geometry. To suppress this effect and stabilize the metastable phase, In3+ without ns electrons is introduced into the lattice of (C6H5NH3)6SbCl9·H2O, as a result, the changed coordination environment, including band structure, lattice constant and intermolecular electronic interaction, not only inhibits the structure transformation, but also leads to an enhanced PL efficiency (83.37 %) at ∼ 600 nm. This work promotes the understanding of structure-luminescence-stability relationship in organic–inorganic materials, and provides a new insight for further searching for high-performance lead-free perovskite luminescent materials.