Color-Stable Blue Light-Emitting Diodes Enabled by Effective Passivation of Mixed Halide Perovskites

Bandgap tuning through mixing halide anions is one of the most attractive features for metal halide perovskites. However, mixed halide perovskites usually suffer from phase segregation under electrical biases. Herein, we obtain high-performance and color-stable blue perovskite LEDs (PeLEDs) based on mixed bromide/ chloride three-dimensional (3D) structures. We demonstrate that the color instability of CsPb(Br1-xClx)(3) PeLEDs results from surface defects at perovskite grain boundaries. By effective defect passivation, we achieve color-stable blue electroluminescence from CsPb(Br1-xClx)(3) PeLEDs, with maximum external quantum efficiencies of up to 4.5% and high luminance of up to 5351 cd m(-2) in the sky-blue region (489 nm). Our work provides new insights into the color instability issue of mixed halide perovskites and can spur new development of high-performance and color-stable blue PeLEDs.

Automated summary

Bandgap tuning through mixing halide anions is an attractive feature for metal halide perovskites, but mixed halide perovskites often exhibit phase segregation under electrical biases. By effectively passivating surface defects, researchers have achieved color-stable blue electroluminescence from mixed bromide/chloride perovskite LEDs, providing new insights into the color instability issue and encouraging further development of high-performance and color-stable blue PeLEDs.