Highly luminescent and stable MAPbBr3 quantum dot fabrication via a hybrid capping ligand

Perovskite quantum dots (PEQDs) are next-generation quantum dot materials that have attracted attention in various areas such as display, radiation scintillator, and photodetector. However, PEQD defects that occur for various reasons hinder the commercialization of PEQDs. Herein, we reported a new strategy for a hybrid ligand comprising 1-octanethiol (OT) and octylammonium bromide that can passivate the defects of PEQD and effectively reduce the Stokes shift. First, the increase in the OT concentration in hybrid ligands leads to an increase in the PEQD size and a decrease in the Stokes shift. Second, OT in hybrid ligands can stabilize the PEQD solution by binding to an MA ion, which is easily degraded by atmospheric oxygen, thereby suppressing the generation of metallic Pb that serves as a defect in PEQDs. Consequently, PEQDs by hybrid ligands reduced the defects, particularly metallic Pb, leading to strong green emission with low Stokes shift with a photoluminescence quantum yield of 99.3 % and high stability under atmospheric conditions. [Display omitted] •Hybrid ligand can stabilize the perovskite quantum dot.•Hybrid ligand shows the highly luminescent perovskite quantum dot.•Hybrid ligand can control the perovskite quantum dot size and Stoke shift.•Hybrid ligand can eliminate the perovskite vacancies leading to defect.