Room-Temperature Synthesis of Two-Dimensional Hexagonal Boron Nitride Nanosheet-Stabilized CsPbBr3 Perovskite Quantum Dots

Poor stability always restricts the application of all-inorganic perovskite quantum dots (PQDs). Herein, 2D hexagonal boron nitride ( h-BN) nanosheets were firstly utilized to stabilize CsPbBr₃ PQDs through a facile heterogeneous nucleation-growth process at room temperature. In synthesized h-BN/CsPbBr₃ PQD nanocomposites, cubic CsPbBr₃ PQDs adhere on h-BN nanosheet surfaces, benefiting from the high specific surface area and abundant mesopores of 2D nanosheets. The nanocomposites prepared at optimized loading of h-BN nanosheets and reaction time display good green-emitting performance with a narrow full width at half maximum of ∼20.0 nm and high color purity of 92.0%. Unique 2D structure and excellent thermal conductivity of h-BN nanosheets endow the h-BN/CsPbBr₃ PQD nanocomposites with significantly enhanced humidity stability and thermal stability. The white light-emitting diodes (LEDs) assembled with green-emitting nanocomposites, a blue chip, and a commercial red phosphor possess a low correlated color temperature of 4190 K, color-rendering index of 76, and high luminous efficacy of 57 lm/W. Further, the color gamut of the synthetic white light based on blue-emitting h-BN/CsPbBr_1.5Cl_1.5 PQDs, green-emitting h-BN/CsPbBr₃ PQDs, and red-emitting h-BN/CsPbBr_1.2I_1.8 PQDs is 114% of the National Television System Committee standard. This work paves a new way for utilizing 2D nanomaterials to synthesize stable all-inorganic PQDs for white LEDs and displays.