Efficient and Stable Self-Assembly Blue-Emitting CsPbBr₃ Nanoplatelets with Self-Repaired Surface Defects

The development of efficient and stable blue-emitting CsPbX3 is critically important for the balance of the three primary colors and advanced lighting and displays. Here, a single ligand passivation strategy is proposed to synthesize highly efficient self-assembly CsPbBr3 nanoplatelets (NPLs). With such a single ligand passivation strategy, the Br vacancy of the Pb–Br octahedron is eliminated effectively. The ultrafast exciton dynamic processes confirmed by transient absorption indicates the lower defect density for the self-assembly CsPbBr3 NPLs. Obvious emission improvement of the pristine CsPbBr3 NPLs was observed as the resting time increased to 24 h, which is associated with self-repaired surface defects and suppressed nonradiative recombination. Photoluminescence (PL) intensity of the CsPbBr3 NPLs in deionized water for 20 h was decreased by 40%, while PL still kept about 73% of the initial intensity even after the continuous irradiation of 395 nm UV for 30 h. The efficient and stable blue-emitting CsPbBr3 NPLs provide great opportunities to develop efficient lighting and displays.