Uncovering the Performance Enhancing Mechanism of Methanesulfonate Ligands in Perovskite Quantum Dots for Light-Emitting Devices.

Perovskite quantum dots (PQDs) have attracted more and more attention in light-emitting diode (LED) devices due to their outstanding photoelectric properties. Surface ligands not only enable size control of quantum dots but also enhance their optoelectronic performance. However, the efficiency of exciton recombination in PQDs is often hindered by the desorption dynamics of surface ligands, leading to suboptimal electrical performance. In this study, sodium methanesulfonate (NaMeS) was successfully introduced during PQD synthesis and ligand exchange, where the S═O groups effectively interacted with the perovskite components. The NaMeS-modified PQD films exhibited significantly improved surface morphology, radiative recombination efficiency, and carrier mobility. Consequently, Pe-LEDs derived from NaMeS-capped PQDs achieved a remarkable enhancement in performance with a maximum external quantum efficiency of 9.41%. This work thus provides a novel and effective strategy for the development of high-performance PQDs and their applications in LEDs.