Room temperature circularly polarized emission in perovskite nanocrystals through bichiral-molecule-induced lattice reconstruction

Summary

Circularly polarized luminescence in halide organic-inorganic perovskite nanocrystals is attainable using chiral organic components. However, this phenomenon is typically restricted to cryogenic conditions due to exciton spin-flip processes. Here, we present a chiral-molecule-mediated lattice reconstruction method to induce circularly polarized luminescence in hybrid perovskite nanocrystals at room temperature. By employing a chiral spacer in the crystal lattice and another chiral ligand on the crystal surface, we enhance asymmetric light absorption and delay the spin flip of photogenerated charge carriers, as confirmed by circularly polarized pump-probe transient absorption spectroscopy. This cooperative interaction among chiral molecules results in circularly polarized emission with a polarization degree of 5.2% in mixed-phase perovskite nanocrystals. We demonstrate the application of chiral perovskites as nanoscintillators, where X-ray-induced asymmetric photopolymerization is achieved at room temperature through emitted circularly polarized radioluminescence. This property facilitates controlled in situ asymmetric photochemical reactions, fostering advancements in materials, drug delivery, and bioengineering applications.