Suppressed surface defect via ligand engineering with 2-hexyldecanoic acid for high luminescence and stable CsPb1−xNixBr3 perovskite quantum dots†

Perovskite quantum dots (PQDs) have gained considerable attention as fluorescent materials because of their exceptional optical properties. However, PQDs are vulnerable to environmental conditions because of ionic bonds, necessitating improvements in their stability. Recent research has focused on preventing phase transition through B-site doping of the perovskite structure or ligand modification to suppress surface defects. The carboxyl ligand, which is an X-type ligand, binds to the B-site of the particle. To the best of our knowledge, an interaction between carboxyl ligand modification and B-site ion doping has not been reported. In this study, we present a synthesis strategy for stable PQDs with tunable optical properties. This approach involves the simultaneous doping of the B-site and modification of the X-type ligand, resulting in the formation of stable PQDs with enhanced performances. The results indicate that the luminescence properties of the particles are enhanced, and the phase transition is prevented through the B-site ion doping process. The modification of the carboxyl ligand to 2-hexyldecanoic acid (DA) improves the luminescence characteristics and enhances luminescence stability. Consequently, DA–CsPb_1−xNi_xBr₃ PQDs provide a quantum yield (QY) of 84.71% and stability when exposed to conditions such as ambient temperature, heat, and moisture. Therefore, we propose a convenient approach for suppressing the decomposition of PQDs during the manufacturing process.