Spatial Crystallization Homogenization Boosts Scalable Perovskite Light‐Emitting Diodes

Conventional antisolvent dripping methods face fundamental limitations in controlling crystallization kinetics, particularly manifesting as instantaneous nucleation and severe spatial inhomogeneity in scaled‐up perovskite films. Herein, a microdroplet‐phase antisolvent deposition technique is developed that establishes a controlled crystallization environment through delayed nucleation kinetics via mild antisolvent interaction and uniform microdroplet diffusion across extended substrates. The resulting small‐area (0.1 cm 2 ) device attains an external quantum efficiency (EQE) of 30.98% at 515 nm, ranking among the best‐performing green perovskite light‐emitting diodes (PeLEDs). A remarkable EQE of 23.21% is also realized when the active area expands to 6.25 cm 2 . This work provides a fundamental advancement in perovskite crystallization control and demonstrates a viable pathway toward industrial‐scale production of PeLEDs.