Metal Halide Perovskite Nanocrystals for Near-Infrared Circularly Polarized Luminescence with High Photoluminescence Quantum Yield via Chiral Ligand Exchange

Using ligand exchange on FAPbI(3) perovskitenanocrystals(PNCs) surface with chiral tridentate l-cysteine (l-cys) ligand, we successfully prepared chiral FAPbI(3) PNCsthat show circularly polarized luminescence (CPL) (dissymmetry factor; g (lum) = 2.1 x 10(-3)) inthe near-infrared (NIR) region from 700 to 850 nm and a photoluminescence quantum yield (PLQY) of 81%. The chiral characteristics of FAPbI(3) PNCs are ascribed to induction by chiral l/d-cys, and the high PLQY is attributed to the passivation of the PNCsdefects with l-cys. Also, effective passivation of defectson the surface of FAPbI(3) PNCs by l-cys resultsin excellent stability toward atmospheric water and oxygen. The conductivityof the l-cys treated FAPbI(3) NC films is improved,which is attributed to the partial substitution of l-cysfor the insulating long oleyl ligand. The CPL of the l-cysligand treated FAPbI(3) PNCs film retains a g (lum) of -2.7 x 10(-4). Thisstudy demonstrates a facile yet effective approach to generating chiralPNCs with CPL for NIR photonics applications.