Multifunctional Interfacial Molecular Bridge for Highly Efficient and Mechanically Robust Flexible Blue Perovskite Light-Emitting Diodes.

Metal halide perovskites have emerged as promising candidates for flexible optoelectronics, yet the development of efficient blue-emitting devices remains hindered by low charge utilization and poor mechanical durability. Herein, we propose a multifunctional molecular bridging strategy using trifluoroacetate (TFA-)-based molecule to construct efficient and mechanically robust flexible blue perovskite light-emitting diodes (PeLEDs). The TFA- bridge enhances interfacial adhesion and creates a stress-redistributing network at the interface, effectively dissipating bending-induced strain. Concurrently, this molecular bridge effectively modulates the crystallization of low-dimensional perovskites through competitive coordination and hydrogen bond-guided phase reorganization, facilitating efficient exciton confinement and energy transfer. The resulting flexible blue PeLEDs achieve an external quantum efficiency of 20.05% and outstanding bending durability, maintaining over 90% of their initial performance after 2000 cycles at a 5 mm radius. This work demonstrates the dual role of biomimetic molecular bridges in simultaneously stabilizing the bulk perovskite phase and the device interface, providing a generalizable route toward high-performance and mechanically robust flexible optoelectronics.