Circularly Polarized Luminescence in Achiral Tin-Based Perovskites via Structural Isomer-Driven Coordination Interaction.

A chiral bidentate ligand, (R)-(-)-1-amino-2-propanol (denoted as R1) or (R)-(-)-2-amino-1-propanol (denoted as R2), was used to modify achiral 2D tin-based perovskite HDASnBr4 (HDA: 1,6-hexamethylenediamine) to form R1-HDASnBr4 or R2-HDASnBr4 by an acid precipitation method. R1-HDASnBr4 exhibits a near-unity photoluminescence quantum yield (PLQY) and strong yellow circularly polarized luminescence (CPL) with a luminescence asymmetry g-factor (|glum|) of 8.3 × 10-3, while R2-HDASnBr4 shows a PLQY of 95% and |glum| of 3.2 × 10-3. Both exhibit strong CPL activities, attributed to the significant centro-asymmetric distortion induced by the interaction between the chiral ligand and the inorganic lattice of 2D perovskites. The |glum| of R1-HDASnBr4 is 2.6× that of R2-HDASnBr4, resulting from the direct coordination of the hydroxyl group attached to the chiral carbons in R1 with the [SnBr6]4- inorganic framework, which induces a higher degree of distortion than the amino group in R2. Furthermore, we explored the potential of R1-HDASnBr4 as a chiral inducer and a CPL source to facilitate asymmetric polymerization. This work offers a simple strategy to introduce chirality to achiral perovskites.