First-Principles Studies of Luminescence in Ce doped Inorganic Scintillators

TL;DR

This study uses density functional theory to identify key electronic properties that predict bright Ce-doped scintillators, leading to the discovery of a new promising material through high-throughput computational screening.

Contribution

The paper introduces a systematic first-principles computational approach to predict and discover new bright Ce-activated scintillator materials, validated by experimental synthesis.

Findings

Identified criteria for bright Ce scintillators based on electronic structure parameters.

Predicted and experimentally confirmed Ba2YCl7:Ce as a new bright scintillator.

Developed a high-throughput method for screening potential scintillator materials.

Abstract

Luminescence in Ce doped materials corresponds to a transition from an excited state where the lowest Ce 5d level is filled to the ground state where a single 4f level is filled. We have performed theoretical calculations based on Density Functional Theory to calculate the ground state band structure of Ce-doped materials as well as the Ce3+ excited state. The excited state calculations used a constrained occupancy approach by setting the occupation of the Ce 4f states to zero and allowing the first excited state above them to be filled. These calculations were performed on a set of Ce doped materials that are known from experiment to be scintillators or non-scintillators to relate theoretically calculable parameters to measured scintillator performance. From these studies we developed a set of criteria based on calculated parameters that are necessary characteristics for bright Ce activated scintillators. Applying these criteria to about a hundred new materials we developed a list of candidate materials for new bright Ce activated scintillators. After synthesis in powder form one of these new materials (Ba2YCl7:Ce) was found to be a bright scintillator. This approach, involving first-principles calculations of modest computing requirements was designed as a systematic, high-throughput method to aid in the discovery of new bright scintillator materials by prioritization and down-selection on the large number of potential new materials.