Circularly polarized electroluminescence from thermally evaporated core-shell perovskite-based light-emitting diodes

Abstract

Spin light-emitting diodes (spin-LEDs) have garnered significant attention for their potential applications in quantum information technology, three-dimensional displays, and secure optical communications. Although solution-processed spin-LEDs have advanced rapidly, they exhibit limited scalability and reproducibility. By contrast, spin-LEDs fabricated via thermal evaporation offer scalability and reproducibility but remain underdeveloped owing to uncontrolled crystallization and significant nonradiative recombination. In this study, we developed efficient perovskite spin-LEDs via multisource sequential evaporation utilizing PbBr2, chiral [1,1 ' binaphthalene]-2,2 '-diylbis[1,1-diphenyl-1,1 '-phosphineoxide] (BINAPO) molecules, and CsBr. The chiral BINAPO molecules with bidentate (P = O)2 groups surround the CsPbBr3 lattice to form a perovskite-BINAPO structure. This structure controls perovskite crystallization, passivates surface defects, and enhances the exciton binding energy. Furthermore, the chiral-induced spin-selectivity effect of the chiral BINAPO shell alters the spin states of the injected carriers, which are subsequently transferred to the perovskite core, leading to the emergence of chiro-optical properties in the perovskite. The resulting perovskite spin-LEDs achieve maximum external quantum efficiencies of 13.20% (R-target) and 12.35% (S-target), in conjunction with electroluminescence dissymmetry factors of -0.124 (R-target) and 0.106 (S-target). This study presents the first demonstration of circularly polarized electroluminescence from thermally evaporated perovskite spin-LEDs, building a scalable platform for high-efficiency spin optoelectronics and practical perovskite spin-LEDs integration.