Multifunctional Crystal Regulation Enables Efficient and Stable Sky-Blue Perovskite Light-Emitting Diodes

Perovskite light-emitting didoes (PeLEDs) have shown considerable potential in solution-processable display applications. However, the performance of blue PeLEDs in terms of efficiency and stability hinders their practicality on account of severe trap-mediated nonradiative recombination losses and halide phase segregation. To ameliorate these issues, mixed-halide sky-blue perovskite materials are strategically modulated through crystal defect passivation with a trifurcate isocyanate oligomer, which leads to the synergistical suppression of charge trap density and halide ion migration. The proposed approach enables the performance improvement for sky-blue PeLEDs, exhibiting a peak external quantum efficiency of 14.82% and spectrally stable emission at 487 nm. In addition, prolonged operational lifetime and enhanced capability of moisture resistance are achieved simultaneously, approaching a half-lifetime of ≈2900 s at an initial brightness of 178 cd m –2 .