Improved Uniformity of Electrical Injection Enables Bright and Suppressed Efficiency Roll-Off Inverted Light-Emitting Diodes Based on FAPbBr3

Perovskite light-emitting diodes (PeLEDs) have been substantiated as promising candidates for high-efficiency electroluminescence. However, the maximum external quantum efficiency (EQE) of state-of-the-art PeLED is typically achieved at relatively low current densities and exhibits severe efficiency roll-off under intense electrical excitation, thereby restricting their development in high-power applications. Specifically, the uniformity of electrical injection has usually been neglected in optimization strategies, primarily due to inadequate comprehension of the microscale injection. In this study, a modified deposition method, marked static reaction deposition, is developed. The residence of precursor solution on the magnesium-doped zinc oxide substrate enables the perovskite crystalline growth homogeneously, thereby enabling the construction of a perovskite polycrystalline emission film with an ultra-low root mean square roughness of 0.72 nm. The resultant enhancement in electrical injection uniformity effectively suppresses localized carrier over-injection and mitigates EQE roll-off. The fabricated PeLED demonstrates a maximum luminance of 590,000 cd m −2 at a high current density of 964 mA cm −2 and maintains an EQE exceeding 10% at current densities up to 1000 mA cm −2 . These findings delineate a novel and broadly applicable optimization paradigm for realizing high-luminance, low roll-off, and efficient PeLEDs.