Component homogenization enables spectrally stable deep-blue perovskite light-emitting diodes

Achieving efficient and spectrally stable deep-blue emission is crucial for full-color displays based on perovskite light-emitting diodes (PeLEDs). Although Cl/Br mixing enables precise bandgap tuning, its rapid crystallization kinetics introduce defects and inhomogeneity, leading to phase separation. To address this challenge, we propose a kinetic-modulation strategy using a functional dopant [indium(I) chloride, InCl] to retard the crystallization process of mixed-halide perovskites. This slow crystallization suppresses non-radiative recombination losses and eliminates halide segregation, resulting in a homogenized halide distribution and reduced defect density. Consequently, the fabricated deep-blue PeLED achieves an external quantum efficiency of 5.2% at 460 nm and, more importantly, exhibits substantially enhanced operational spectral stability.