Helical Perovskite Nanowires with Strong Circularly Polarized Luminescence Self-Assembled from Red-Emitting CsPbI₃ Quantum Dots Following Chiral Ligand Exchange

Circularly polarized luminescence (CPL) of chiral perovskite nanocrystals is crucial for applications such as spin-polarized light-emitting diodes and chiral photodetectors. However, the reported luminescence dissymmetry factors are often too low for practical applications; it is also important for CPL wavelengths to cover the red emission range for display applications. Herein, we realized helical perovskite nanowires self-assembled from red-emitting CsPbI₃ quantum dots (QDs) with a strong CPL signal around 640 nm, which was enabled by chiral ligand R-/S-binaphthyl phosphoric acid. The formation of CsPbI₃ nanowires from perovskite QDs occurred by oriented attachment; QDs remaining in solution attached at the surface of the nanowires, forming helical structures. The films produced from these chiral nanowires demonstrate high dissymmetry factors of 1.1 × 10^-2 and 2.3 × 10^-2 for absorption and luminescence, respectively, surpassing many previously reported chiral nanomaterials. We employed multilayer nanowire films as chiral filters, generating left- and right-handed CPL.