Unity emission in organic phosphonium antimony halide for high color rendering white LED

Metal halides have attracted increasing attention in luminescent applications because of their fantastic properties in optoelectronics and easy solution processability. However, toxicity of Pb element and low photoluminescence quantum yield (PLQY) hamper their practical application. Herein, we report a lead-free zero-dimensional antimony (Ⅲ) hybrid halide (EPP)2SbCl5 ⋅CH2Cl2 (EPP = Ethyltriphenylphosphonium), in which inorganic luminescent center [SbCl5]2- are surrounded by organic ligands, forming a perfect host-guest system and exhibiting unprecedented photophysical properties. The (EPP)2SbCl5 ⋅CH2Cl2 exhibits a bright orange-red emission located at 623 nm, a near-unity PLQY of 97.09 %, and a large Stokes shift of 253 nm. The characterization of photophysical properties shows that broadband emission with microsecond decay lifetime (6.98 μs) is derived from self-trapped exciton emission. Together highly efficient and ultra-stable luminescence performance enable (EPP)2SbCl5 ⋅CH2Cl2 as excellent down-conversion phosphor to successfully fabricate white light-emitting diodes (LEDs) device with a color rendering index of 95. It is proved that the prepared 0D antimony hybrid halide with ultrabroad-band emission and near-unity PLQY is a promising solid-state lighting luminescent material.