Chiral perovskites with a unique 1D chain structure: impact of chiral ligand geometry on local inversion asymmetry and chiral-induced spin selectivity

Abstract

Chiral hybrid organic–inorganic perovskites (HOIPs) have demonstrated significant potential in spintronics, primarily due to inversion symmetry breaking as well as strong spin–orbit coupling (SOC) arising from their heavy-element composition. Numerous studies have confirmed that chiral perovskites exhibit superior chiral-induced spin selectivity (CISS). However, the key factors underlying such pronounced spin polarization selectivity, especially within organic–inorganic hybrid systems, are not well understood. This oversight marks a critical area for deeper exploration in spintronics research. We introduce R/S-1-amino-2-propanol (R/S-HP1A) as a chiral spacer to synthesize chiral perovskites, (R/S-HP1A)PbI₃, characterized by a distinct 1D chain structure with two layers of inorganic octahedrons in each chain. In (R/S-HP1A)PbI₃, the chiral carbon locates away from the perovskite's inorganic skeleton, resulting in a slight degree of inversion asymmetry within the inorganic sublattice while maintaining a global chiral space group (P2₁2₁2₁). As a result, (R/S-HP1A)PbI₃ exhibits small Rashba–Dresselhaus spin-splitting, a purely in-plane spin texture, a short spin lifetime (4 ± 1.5 ps) and a relatively low polarization degree of the CISS effect (58% and 66% for R- and S-forms, respectively), in comparison to other reported low-dimensional chiral perovskites. These findings emphasize that the local inversion asymmetry of the inorganic octahedrons, beyond global chirality, significantly influences the CISS effect in chiral perovskites, which is important for targeted improvements in spintronic applications.