Zhejiang University researchers make new breakthrough in bright and stable red perovskite LEDs at high current density

PeLEDs have become the next generation of light-emitting technology. Recently, David Di/Baodan Zhao CEJ from Zhejiang University have made breakthroughs in realizing highly stable near-infrared and green light-emitting diodes. However, the operating lifetime (T50) of visible PeLEDs at high current density (>10 mA cm-2) is still unsatisfactory (usually <100 hours), limiting the possibility of solid-state lighting and AR/VR applications. This problem becomes more obvious for mixed halide (e.g., red and blue) perovskite emitters, where key challenges such as halide segregation and spectral instability exist.

Here, they demonstrate bright and stable red PeLEDs based on mixed halide perovskites, with a T50 lifetime of ~357 hours at currents ≥25 mA cm-2, which is a record for the operational stability of visible PeLEDs at high current density. The device produces strong and stable emission with a maximum brightness of 28,870 cd m-2 (radiance: 1584 W sr-1 m-2), a record high for red PeLEDs. The key to this demonstration is the introduction of sulfonamide, a dipolar molecular stabilizer that effectively interacts with ions in the perovskite emitter. It suppresses halide segregation and migration to the charge transport layer, thereby improving the stability and brightness of hybrid halide PeLEDs.