Defect Passivation for Red Perovskite Light-Emitting\nDiodes with Improved Brightness and Stability

Efficient and stable\nred perovskite light-emitting diodes (PeLEDs)\nare important for realizing full-color display and lighting. Red PeLEDs\ncan be achieved either by mixed-halide or low-dimensional perovskites.\nHowever, the device performance, especially the brightness, is still\nlow owing to phase separation or poor charge transport issues. Here,\nwe demonstrate red PeLEDs based on three-dimensional (3D) mixed-halide\nperovskites where the defects are passivated by using 5-aminovaleric\nacid. The red PeLEDs with an emission peak at 690 nm exhibit an external\nquantum efficiency of 8.7% and a luminance of 1408 cd m–2. A maximum luminance of 8547 cd m–2 can be further\nachieved as tuning the emission peak to 662 nm, representing the highest\nbrightness of red PeLEDs. Moreover, those LEDs exhibit a half-life\nof up to 8 h under a high constant current density of 100 mA cm–2, which is over 10 times improvement compared to literature\nresults.