Efficient lead-free antimony halide light-emitting diodes with 22% external quantum efficiency via a binary host-guest architecture

Lead halide emitters hold great promise for next-generation light-emitting diodes (LEDs), but their heavy metal toxicity poses major barriers to commercialization. Therefore, developing efficient lead-free metal halide LEDs is highly desirable but remains a big challenge. Here, we report solution-processed lead-free antimony halide-based LEDs with an external quantum efficiency of 22% and a current efficiency of 55.84 candelas per ampere. The exceptional device performance is achieved through a binary host-guest architecture using a zero-dimensional organic-inorganic antimony(III) halide, which exhibits bright emission with a near-unity photoluminescence quantum yield. Optical and photophysical studies combined with theoretical calculations reveal the mechanism underlying its highly efficient self-trapped exciton emission. Efficient LEDs were achieved by doping (AylPPh₃)₂SbCl₅ into a binary host system, which improved film morphology, enhanced charge carrier mobility, and achieved better carrier balance. These enhancements resulted in substantially superior device performance compared to nondoped LEDs with (AylPPh₃)₂SbCl₅ as a neat emissive layer.