Study on the mechanism of organic ligand-assisted synthesis of superwater-stable CsPbBr3 quantum dots

Although lead halide perovskites have demonstrated excellent optical properties, their commercialization has been hindered due to environmental stability issues, in particular water stability. Here, CsPbBr3@PbBr(OH) perovskite quantum dots (PQDs) were successfully synthesized at room temperature with the assistance of organic ligands. These PQDs exhibited excellent water stability, which were validated by the retention of more than 90% of the original luminescence intensity under ultrasonic treatment and water immersion for up to one year. The photoluminescence quantum yield (PLQY) of the CsPbBr3@PbBr(OH) powder reached 51%, which is similar to the PLQY (53%) of pure CsPbBr3 prepared by hot-injection by us. In addition, the Lewis acidity and basicity of the organic ligand will affect the synthesis rate of PbBr(OH) during the reaction, which further affects the number and size of quantum dots, the color of luminescence could be modified. Due to the CsPbBr3@PbBr(OH) has such excellent stability and high PLQY, we tested its potential as a perovskite LED. The emission attenuation is only 7% after the LED device works continuously for 12 h.