Efficient solution-processed light-emitting diodes based on organic-inorganic hybrid antimony halides

Organic-inorganic hybrid antimony halides are emerging emitters for solution-processed light-emitting diodes. However, achieving high-efficiency electroluminescence remains challenging resulting from the non-radiative recombination within emitters and inferior charge transport within device. Here, we develop an organic cation engineering to design a carbazole-functionalized triphenyl(9-ethyl-9H-carbazol-3-yl) phosphonium (TPPEtCz+), which enables a (TPPEtCz)2Sb2Br8 film with good luminescence and achieves an improved charge transport within device. The TPPEtCz+ facilitates strong hydrogen bonding with the [Sb2Br8]2− species and dichloromethane solvent, resulting in a more complete crystal restructuring, thus improving the quality of films. Moreover, non-covalent π–π interactions between carbazole moieties of (TPPEtCz)2Sb2Br8 and benzimidazole moieties of electron-transport TPBi modify the interfacial contact that promotes electron transport and injection. Consequently, our light-emitting diodes reach a peak external quantum efficiency of 19.4% and half-lifetime of 10,190 min at 100 cd m−2. These discoveries provide critical insights into the cation design of hybrid devices that are promising for practical applications. Ma et al. report an organic cation engineering strategy to improve the luminescent properties and charge transport in organic-inorganic antimony halide films, enabling red LEDs with efficiency up to 19.4% and half-lifetime of 10,190 min. Large-area (12.15 cm2) LEDs show efficiency of 14.2%.