Surficial Homogenic Effect Enables Highly Stable Deep‐Blue Perovskite Light‐Emitting Diodes

The device performance of deep-blue perovskite light-emitting diodes (PeLEDs) is primarily constrained by low external quantum efficiency (EQE) especially poor operational stability. Herein, we develop a facile strategy to improve deep-blue emission through rational interface engineering. We innovatively reported the novel electron transport material, 4,6-Tris(4-(diphenylphosphoryl)phenyl)-1,3,5-triazine (P-POT2T), and utilized a sequential wet-dry deposition method to form the homogenic gradient interface between electron transport layer (ETL) and perovskite surface. Unlike previous reports that achieved carrier injection balance by inserting new interlayers, our strategy not only passivated uncoordinated Pb