Mixed-Halide Perovskites with Halogen Bond Induced Interlayer Locking Structure for Stable Pure-Red PeLEDs.

Mixed-halideperovskites enable precise spectral tuning acrossthe entire spectral range through composition engineering. However,mixed halide perovskites are susceptible to ion migration under continuousillumination or electric field, which significantly impedes the actualapplication of perovskite light-emitting diodes (PeLEDs). Here, wedemonstrate a novel approach to introduce strong and homogeneoushalogen bonds within the quasi-two-dimensional perovskite latticesby means of an interlayer locking structure, which effectively suppressesion migration by increasing the corresponding activation energy. Variouscharacterizations confirmed that intralattice halogen bonds enhancethe stability of quasi-2D mixed-halide perovskite films. Here, wereport that the PeLEDs exhibit an impressive 18.3% EQE with pure redemission with CIE color coordinate of (0.67, 0.33) matching Rec. 2100standards and demonstrate an operational half-life of & SIM;540min at an initial luminance of 100 cd m(-2), representingone of the most stable mixed-halide pure red PeLEDs reported to date.