Decyl disulfide surface treatment improved photoluminescence quantum yield and stability of blue-emitting CsPbBr3 nanoplatelets

Improving the photoluminescence quantum yields (PL QYs) and stability of blue-emitting CsPbBr3 nanoplatelets (NPLs) is essential for the application in high-quality displays. Herein, highly luminescent CsPbBr3 NPLs with PL peak at 462 nm were prepared by a modified supersaturated recrystallization synthesis strategy at room temperature. The resulting blue CsPbBr3 NPLs show high PL QY of 98% and a full width at half maximum of 13 nm, benefiting from the decyl disulfide (DF) surface treatment. Besides, the DF-treated CsPbBr3 NPLs show lower Urbach energy (15 meV) and more outstanding water, acetone, and UV-light resistance stabilities than the pristine ones, suggesting that the surface ligand treatment can reduce Br− vacancy defects and inhibit the non-radiative recombination process. Based on the temperature-dependent PL, the exciton binding energy of CsPbBr3 NPLs is found to increase from 109 to 201 meV after DF treatment. Finally, light-emitting diodes based on the treated CsPbBr3 NPLs were fabricated.