Solution Synthesis and Light-Emitting Applications of One-Dimensional Lead-Free Cerium(III) Metal Halides

Combining rare earth elements with the halide perovskite
structure
offers valuable insights into designing nonlead (Pb) luminescent materials.
However, most of these compositions tend to form zero-dimensional
(0D) networks of metal–halide polyhedra, with higher-dimensional
(1D, 2D, and 3D) structures receiving relatively less exploration.
Herein, we present synthesis and optical properties of Cs3CeCl6·3H2O, characterized by its unique
1D crystal structure. The conduction band minimum of Cs3CeCl6·3H2O becomes less localized as a
result of the increased structural dimension, making it possible for
the materials to achieve an efficient electrical injection. For both
Cs3CeCl6·3H2O single crystals
and nanocrystals, we also observed remarkable luminescence with near-unity
photoluminescence quantum yield and exceptional phase stability. Cs3CeCl6·3H2O single crystals demonstrate
an X-ray scintillation light yield of 31900 photons/MeV, higher than
that of commercial LuAG:Ce (22000 photons/MeV); electrically driven
light-emitting diodes fabricated with Cs3CeCl6·3H2O nanocrystals yield the characteristic emission
of Ce3+, indicating their potential use in next-generation
violet-light-emitting devices.