High‐Performance Sky‐Blue Perovskite Spin‐Light Emitting Diodes Due to Chiral Ionic Liquid Implantation and Passivation

Abstract In chiral hybrid perovskites (CHPs), the generation of polarized spin current and the manipulation of spin exciton recombination are expected to produce circularly polarized electroluminescence (CP‐EL) through chiral‐induced spin selectivity (CISS). It opens a new avenue for developing single junction spin light‐emitting diodes (spin‐LEDs). The recent challenge lies primarily in balancing device performance and CP‐EL polarization. Beyond this, blue spin‐LEDs have not been fully realized. It lacks studies for interior spin‐chiroptical properties. Herein, a promising chirality transfer methodology is initiated for fabricating sky‐blue (≈491 nm) spin‐LEDs using synthesized chiral ionic liquids (CILs). They on one side yield the material passivation, giving rise to the chiroptical and electroluminescence (EL) properties. An optimal external quantum efficiency (EQE) of 13.0% with a dissymmetry factor of 0.158 for CP‐EL is obtained. Importantly, this method leads to the elevation of chiral‐induced spin orbit coupling (CISOC) strength up to 0.9717 eV A, with a long decay lifetime over 1 ns for the polarization. A large polarized spin current of approximately 75% is achieved in ambient conditions. This work unlocks the blue spin‐LEDs, with further construction for the spin‐chiroptics and device performance relationship.