Rare-earth metal halide perovskites are promising for deep blue LEDs. Here, Yang et al. report energy transfer between self-trapped exciton and Frenkel exciton in Cs3CeI6 by adding excess CsI during thermal evaporation, resulting in deep blue LEDs with external quantum efficiency of 7.9% at 424 nm.
- Longbo Yang
- Hainan Du
- Jiang Tang
