CsPb(Br/I)₃ Perovskite Nanocrystals for Hybrid GaN-Based High-Bandwidth White Light-Emitting Diodes

The modulation bandwidth of white light-emitting diodes (LEDs) is an important factor in a visible-light communication (VLC) system, which is mainly limited by the down-conversion materials. The broad spectrum and long lifetime of conventional light conversion materials represent an obstacle to future technological developments. Here, we show that inorganic semiconductor perovskite nanocrystals offer a promising alternative nanomaterial. Anion exchange between different perovskite nanocrystals by post-synthesis is a highly efficient protocol to tune the chemical composition and optoelectronic properties of lead halide perovskite nanocrystals. The fine-tuning of the nanocrystal fluorescence is achieved by blending colloidal solutions of CsPb(Br/I)3 lead halide perovskites with different contents of the halide. The tunable optical emission and short fluorescence lifetime (<5 ns) of the nanocrystals are exploited to realize white LEDs with a high modulation bandwidth (0.7 GHz), offering a potential route toward fast, energy-efficient visible-light communication.