Dual Ligand Strategy to Manipulate Growth Kinetics of FAPbBr3 Nanocrystals for High‐Performance Light‐Emitting Diodes

Metal halide perovskite nanocrystals (PeNCs) have emerged as promising materials for next-generation light-emitting diodes (PeLEDs) due to their outstanding optical properties. However, synthesis challenges such as rapid crystallization often introduce defects that degrade device performance. Herein, a dual-ligand approach employing trioctylphosphine oxide (TOPO) and phenylphosphinic acid (PPIA) is introduced to coordinate Pb2⁺ ions, effectively slowing the crystallization process and minimizing defect formation. The obtained PeNCs exhibit a high photoluminescence quantum yield (PL QY) of 93%. Additionally, the PPIA ligand enhances electrical conductivity via π-electron resonance, enabling more efficient charge transport in FAPbBr3 films. As a result, the optimized PeLEDs achieve a peak external quantum efficiency (EQE) of 24.2% and a luminance of 32 840 cd m- 2, significantly outperforming the control devices, which exhibit an EQE of 12.1% and a luminance of 1577 cd m- 2. Furthermore, the operational lifetime of the optimized PeLEDs is 5.3 times longer than that of the control devices. These findings offer a promising pathway for advancing the performance and stability of PeLEDs.