Metal Halide Perovskite Nanocrystals for Near-Infrared Circularly Polarized Luminescence with High Photoluminescence Quantum Yield via Chiral Ligand Exchange
Jianwu Wei, Qiulian Luo, Sengui Liang, Liya Zhou, Peican Chen, Qi Pang, Jin Z. Zhang
Abstract
Using ligand exchange on FAPbI 3 perovskite nanocrystals (PNCs) surface with chiral tridentate l -cysteine ( l -cys) ligand, we successfully prepared chiral FAPbI 3 PNCs that show circularly polarized luminescence (CPL) (dissymmetry factor; g lum = 2.1 × 10 –3 ) in the 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 PNCs defects with l -cys. Also, effective passivation of defects on the surface of FAPbI 3 PNCs by l -cys results in excellent stability toward atmospheric water and oxygen. The conductivity of the l -cys treated FAPbI 3 NC films is improved, which is attributed to the partial substitution of l -cys for the insulating long oleyl ligand. The CPL of the l -cys ligand treated FAPbI 3 PNCs film retains a g lum of −2.7 × 10 –4 . This study demonstrates a facile yet effective approach to generating chiral PNCs with CPL for NIR photonics applications.