DMAPbI3-Enabled Synthesis of Stable CsPbI3 Nanocrystals for Light-Emitting Diodes With 27.5% External Quantum Efficiency

The synthesis of perovskite nanocrystals for light-emitting diodes typically employs poorly controlled ion-mediated precipitation processes, suffering from low photoluminescence quantum yield (PLQY), inhomogeneous morphology, and poor stability. Herein, by adjusting the nucleation method with a new type of precursor, namely “DMAPbI 3 ”, high-quality and low-defect-density perovskite CsPbI 3 nanocrystals were successfully synthesized, with PLQY of 93% emitting at 659 nm. Particularly, the CsPbI 3 nanocrystals exhibit enhanced environmental stability, maintaining ∼70% of their initial photoluminescence intensity after 6 h of UV irradiation exposure or 100°C aging. Utilized as the luminescent layer, the fabricated perovskite LED (PeLED) device shows a peak EQE of 27.5%, representing an almost two-fold enhancement compared to 14.7% for the control PeLED device. This simple and efficient approach is well-suited for large-scale production and practical applications.