Enhancing Photoluminescence and Stability of CsPbI3 Perovskite Quantum Dots via Cysteine Post-Processing

Abstract

Red-emitting cesium lead iodide (CsPbI3) perovskite quantum dots (CQDs) are extremely unstable due to their structural composition and the weak binding force of ligands on the surface of nanocrystals. Herein, we report an effective method to enhance the photoluminescence and stability of CQDs by simple post-processing with cysteine (Cys). Compared to the pristine CQDs with a photoluminescence quantum yield (PLQY) of 38.61%, the Cys-processed one has fewer surface defects, obtaining a PLQY of 70.77%, nearly twice as much as the pristine samples, and, simultaneously, the Cys-processed CQDs retained more than 86% of the initial PL intensity after 20 days of storage in the atmosphere. This research provides a new idea for the preparation of high-performance and red-emitting quantum dots.

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

“…This is attributed to the fact that shortchain ligands L-cys can overcome the steric hindrance brought by long-chain ligands (OAm or OA) to approach the surface of nanocrystals, effectively passivating defects and reducing nonradiative recombination. 35 We further investigated the time-resolved PL (TRPL) of Lcys treated FAPbI 3 PNCs, as shown in Figure 1f. The doubleexponential function is used to fit the TRPL curve well, 36 and all parameters are listed in Table S1.…”

“…Moreover, the PL intensity of l -cys treated FAPbI 3 PNCs is enhanced compared to the control sample (Figure e). This is attributed to the fact that short-chain ligands l -cys can overcome the steric hindrance brought by long-chain ligands (OAm or OA) to approach the surface of nanocrystals, effectively passivating defects and reducing nonradiative recombination …”