Achieving Near-unity Photoluminescence Quantum Yields in Organic-Inorganic Hybrid Antimony (III) Chlorides with the [SbCl 5 ] Geometry.

Hybrid organic-inorganic antimony halides have attracted increasing attention due to the non-toxicity, stability, and high photoluminescence quantum yield (PLQY). To shed light on the structural factors that contribute to the high PLQY, five pairs of antimony halides with general formula A 2 SbCl 5 and A 2 Sb 2 Cl 8 are synthesized via two distinct methods and characterized. The A 2 SbCl 5 type adopts square pyramidal [SbCl 5 ] geometry with near-unity PLQY, while the A 2 Sb 2 Cl 8 adopts seesaw dimmer [Sb 2 Cl 8 ] geometry with PLQY≈0 %. Through combined data analysis with the literature, we have found that A 2 SbCl 5 series with square pyramidal geometry generally has much longer Sb⋅⋅⋅Sb distances, leading to more expressed lone pairs of Sb III . Additional factors including Sb-Cl distance and stability of antimony chlorides may also affect PLQY. Our targeted synthesis and correlated insights provide efficient tools to precisely form highly emissive materials for optoelectronic applications.