Efficient\nCircularly Polarized Electroluminescence\nEnabled by Low-Dimensional Bichiral Perovskite Nanocrystals

Chiral\norganic–inorganic hybrid perovskite nanocrystals\nhave gained attention as promising materials for circularly polarized\nluminescence emission, owing to their high photoluminescence efficiency\nand superior charge-carrier mobility. However, achieving circularly\npolarized electroluminescence (CPEL) from mixed-phase perovskite nanocrystals\nremains a significant challenge. We present bichiral formamidinium\nlead bromide (FAPbBr<sub>3</sub>) nanocrystals that achieve room-temperature\ncircularly polarized light-emitting diodes (LEDs) via a synergistic\neffect between a chiral interior spacer (methylbenzylamine cation,\nMBA<sup>+</sup>) and a chiral surface ligand (camphorsulfonic acid,\nCSA). The incorporation of MBA<sup>+</sup> induces chiral crystal\nlattices, while CSA ligands, featuring sulfonate groups, effectively\npassivate defects, suppress exciton spin-flip, and enhance conductivity.\nThe resulting circularly polarized LEDs exhibit an enhanced electroluminescence\nasymmetry factor (<i>g</i><sub>EL</sub>) of ∼2 ×\n10<sup>–3</sup>, along with an external quantum efficiency\n(EQE) of 3.1%. These bichiral nanocrystals represent a significant\nadvancement in luminescence efficiency and enantioselectivity, indicating\ntheir potential for next-generation chiroptoelectronic applications.