First-Principles Calculations of Excited-State Processes in Scintillator Materials
EMSL Project ID
48756
Abstract
The objective of the proposed research is to enhance our understanding of and ability to simulate excited states in wide-bandgap materials with the specific goal of predicting the luminescence behavior of activator dopants in inorganic scintillator materials.Inorganic scintillators are widely used as radiation detection materials for applications ranging from high-energy physics to nuclear detection and surveillance. One of the most attractive properties of a scintillator material is its brightness, which depends principally on its yield of electron-hole pairs and its electron-hole pair recombination efficiency. The proposed research focuses on using first-principles calculations to determine activator dopants that will maximize recombination efficiency in materials that have been identified to have high electron-hole pair yields (e.g. LaI3). Specifically, the relative positions of dopant energy levels in the ground and excited states will be calculated for a range of activators (Ce, Pr, Nd, Bi, and Sb) in LaI3 and the nature and mobility of charge carriers in LaI3 will also be determined, as they can strongly influence the efficiency of recombination.
The proposed research will leverage EMSL modeling capabilities implemented in NWChem, namely the ab initio embedded cluster approach. This approach will allow computationally-expensive levels of theory (e.g. hybrid density functional theory (DFT), post-Hartree-Fock, and time-dependent DFT) to be employed to treat activators and charge carriers and thus go beyond supercell ground-state DFT+U calculations, which have been traditionally used to simulate activated scintillators.
Project Details
Project type
Exploratory Research
Start Date
2015-03-09
End Date
2015-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
A portion of the research was performed using EMSL, a DOE Office of Science User Facility sponsored by the Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. This poster was presented at the Academic Research Initiative of the Domestic Nuclear Detection Office 2015.
I was invited to the University of Tennessee at Knoxville to discuss the research I conducted while at PNNL. Here are the slides from the presentation.
This is the technical report I wrote as part of the requirement for the NSIP internship program in which summarizes the work conducted for the above proposal.