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

TL;DR

This paper introduces a new electronic structure descriptor based on band splitting to identify narrow-band red-emitting phosphors, enabling efficient high-throughput discovery of promising materials.

Contribution

The study develops a quantitative descriptor for narrow-band Eu2+-activated emission and demonstrates its effectiveness in screening nitride compounds for new phosphors.

Findings

Identified five new nitride hosts with predicted narrow-band red emission

Established a large Eu2+ 4f7 band splitting (>0.1 eV) as a key descriptor

Provided insights into emission characteristics of rare-earth activators

Abstract

Narrow-band red-emitting phosphors are a critical component in 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 structure 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 2,259 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.