Unveiling the Surface Exciton Dynamics in K-Doped Perovskite Quantum Dots Using Chiral Ligands Enables Efficient White LEDs

Regulation of surface ligands in hybrid organic–inorganic perovskite quantum dots (HOIP QDs) is key to enhancing their optoelectronic properties. However, achieving both high photoluminescence (PL) and long-term stability in chiral HOIP QDs remains challenging. Here, we report the use of chiral anthraquinone derivatives (AQ) as surface ligands, replacing conventional long-chain alkyl ligands, to construct two potassium-doped chiral QDs, (R)AQ-QDs and (S)AQ-QDs. These QDs exhibit high photoluminescence quantum yields (PLQYs) of 98.74 and 97.68%, respectively, along with notable stability. Optical characterization indicates an efficient chirality transfer from the organic ligands to the K_0.23MA_0.77PbBr₃ lattice. Furthermore, density functional theory (DFT) calculations and femtosecond transient absorption (fs-TA) spectroscopy reveal reduced surface trap states, as evidenced by stronger ligand binding and prolonged carrier lifetimes. A white-light-emitting diode (LED) fabricated using the AQ-QDs shows a color rendering index (CRI) of 65.1 and a correlated color temperature (CCT) of 6169 K. The reported work highlights the potential of chiral ligand engineering in improving PL efficiency and stability in perovskite QDs.