Spatial Cross-Linking Strategy for Realizing Stable and Efficient Perovskite Light-Emitting Diodes toward Microscale Displays

Low efficiency, poor stability, and lack of high-resolution patterning hinder the future commercialization of perovskite light-emitting diodes (PeLEDs). Herein, we developed a spatial cross-linking and photolithography strategy to fabricate quasi-2D perovskite films using pentaerythritol tetra(3-mercaptopropionate) (PETMP) and pentaerythritol allyl ether (PAE) as cross-linkers. These cross-linkers containing multiple cross-linking sites facially form hydrophobic and defect-passivating spatial networks at grain boundaries and the surface of perovskite, improving moisture resistance and device efficiency. The cross-linking networks also enhance the lattice rigidity and suppress the ion-migration in perovskite, reducing nonradiative recombination and improving device stability. Consequently, the optimized PeLEDs achieved a high external quantum efficiency (EQE) of 21.36%, and an unencapsulated device exhibits T50 of 47 min at an initial brightness of 1000 cd m–2. Besides, we used photolithography to pattern a perovskite pixel array with a size of ∼80 μm. Our work provides an effective methodology for efficient and stable PeLEDs for high-definition display applications.