Polymer Cross-Linking Strategy Enables High Performance and High Mechanical Stability Flexible Quasi-2D Perovskite Light-Emitting Diodes

Flexible perovskite light-emitting diodes (f-PeLEDs) have become one of the important candidates for lighting and display in wearable electronic devices due to their high flexibility and portability. However, the device performance of f-PeLEDs is much lower than that of rigid devices, mainly due to the lack of mechanically stable perovskite films with good optoelectronic properties. In this work, a multifunctional strategy is proposed to obtain f-PeLEDs with increased mechanical stability and optoelectronic performance. The polylactic acid (PLA) polymer with high flexibility is first incorporated into a quasi-two-dimensional (quasi-2D) film, which undergoes in situ cross-linking and forms a polymer cross-linking network in a quasi-2D film. Moreover, CO functional groups in PLA can coordinate with unsaturated Pb2+ sites to efficiently passivate defects in perovskite films. The excellent flexibility of PLA and dynamic physical cross-linking sites between PLA and the perovskite lattice enhance mechanical stability and still exhibit stable optical properties after repeated bending. Finally, the champion external quantum efficiency (EQE) of 15.94% is successfully implemented and maintains an initial EQE of over 60% after 10 000 bending cycles with a curvature radius of 3 mm. Therefore, the well-designed cross-linking strategy provides an efficient strategy for manufacturing stable f-PeLEDs. A multifunctional polylactic acid nature polymer with high flexibility is first incorporated into a quasi-2D film, which undergoes in situ cross-linking and forms a polymer cross-linking network in a quasi-2D perovskite film. Finally, the champion external quantum efficiency (EQE) of 15.94% is successfully implemented and maintains an initial EQE of over 60% after 10 000 bending cycles with a curvature radius of 3 mm.image