Solvent-Induced Bright Emission in Lead-Free Organic-Inorganic Antimony Bromides with Reversible Transformation

Lead-free low-dimensional organic-inorganic metal halides have gained increasing attention in a wide range of applications due to their low toxicity, outstanding optical performance, and structural tunability. In this work, a general method of incorporating organic molecule into sodium antimony bromides is introduced. The 1D Na₃SbBr₆(C₂H₆OS)₆ and Na₃SbBr₆(C₄H₈OS)₆ single crystals exhibit bright yellow and orange emission with PL peaks at 610 and 664 nm, and high photoluminescence quantum yields (PLQYs) of 85% and 60%, respectively. These two compounds can be reversibly converted into each other by the removal and addition of the organic components. Their exceptional luminescent performance enables them to be used as solid-state phosphors for the fabrication of yellow and orange down-conversion LEDs. A white LED with a high color rendering index (CRI) of 95 is also fabricated by using Na₃SbBr₆(C₂H₆OS)₆ as the yellow phosphor. The universality of this method is demonstrated by synthesizing other members of this family with diverse A-groups, including methylammonium (MA) and formamidinium (FA). This work provides an effective strategy for the development of diverse lead-free and high-performance organic-inorganic hybrid materials and indicates these organic-inorganic hybrid compounds are promising luminescent materials for lighting or displays.