Zn-derived ligand engineering towards stable and bright CsPbI3 nanocrystals for white emitting

Abstract

Lead-halide perovskite nanocrystals (NCs), such as red-emitting CsPbI₃, have gained significant attention due to their promising applications such as display backlights, light-emitting devices, and lasers. However, it is still a great challenge to stabilize CsPbI₃ NCs and further tune and optimize their luminescence properties. In this study, effective Zn-derived ligand engineering was successfully conducted to create highly stable and bright CsPbI₃ NCs for LEDs. The phase stability of CsPbI₃ NCs at room temperature was improved by Zn ion-derived 1-dodecanethiol (DDT) ligand engineering, in which the ratios of Zn/DDT play an important role. Under optimized conditions, the as-treated CsPbI₃ NCs were well dispersed and revealed uniform size distribution and a high photoluminescence (PL) quantum yield of 95.4%. In addition, the treated CsPbI₃ NCs retained the initial PL efficiency after being stored at room temperature for more than 100 days. No phase change occurred for the NCs under UV light irradiation and thermal cycling conditions. Finally, these CsPbI₃ NCs were used for white light-emitting diodes, which had advantages in a wide color gamut and good stability.