Electronic Structure Descriptor for the Discovery of Narrow-Band Red-Emitting Phosphors

Narrow-band red-emitting phosphors
are a critical component of
phosphor-converted light-emitting diodes for highly efficient illumination-grade
lighting. In this work, we report the discovery of a quantitative
descriptor for narrow-band Eu2+-activated emission identified
through a comparison of the electronic structures of known narrow-band
and broad-band phosphors. We find that a narrow emission bandwidth
is characterized by a large splitting of more than 0.1 eV between
the two highest Eu2+ 4f7 bands. By incorporating
this descriptor in a high-throughput first-principles screening of
2259 nitride compounds, we identify five promising new nitride hosts
for Eu2+-activated red-emitting phosphors that are predicted
to exhibit good chemical stability, thermal quenching resistance,
and quantum efficiency, as well as narrow-band emission. Our findings
provide important insights into the emission characteristics of rare-earth
activators in phosphor hosts and a general strategy to the discovery
of phosphors with a desired emission peak and bandwidth.