Highly efficient deep-blue emitting CsPbBr3 nanoplatelets synthesized via surface ligand-mediated strategy

Two-dimensional (2D) CsPbBr 3 nanoplatelets (NPLs) have attracted great attention as one of promising semiconductor nanomaterials due to their large exciton binding energy and narrow emission spectra. However, the labile ionic and weakly bound surfaces of deep-blue emitting CsPbBr 3 NPLs with wide bandgap result in their colloidal instability, thus degrading their optical properties. It is challenging to obtain deep-blue emitting CsPbBr 3 NPLs with excellent optical properties. In this study, high-quality blue-emitting CsPbBr 3 NPLs with tunable thickness were prepared adopting the DBSA-mediated confinement effect based on the hot-injection method. Thanks to the coordination interaction of − SO 3 − of DBSA ligand and the Pb 2+ on the surface of the CsPbBr 3 NPLs, as well as the effective passivation of Br vacancy defects on the surface of NPLs by OAm-Br, the obtained pure-blue CsPbBr 3 NPLs and deep-blue CsPbBr 3 NPLs show high photoluminescence quantum yield (PLQY) of 92 % and 81.2 %, respectively. To the best of our knowledge, this is the highest PLQY recorded for deep-blue emitting CsPbBr 3 NPLs with two monolayers [PbBr 6 ] 4− octahedra. Furthermore, the agglomeration of CsPbBr 3 NPLs due to ligand loss induced by moisture, oxygen, and irradiation was also suppressed by the dual passivation effect of DBSA and OAm-Br. Our work provided a new approach to developing high-performance and stable deep-blue emitting CsPbBr 3 perovskite nanoplatelets.