Luminescence from Self‐Trapped Excitons and Energy Transfers in Vacancy‐Ordered Hexagonal Halide Perovskite Cs2HfF6 Doped with Rare Earths for Radiation Detection
Abstract
Compared to halides Cs2HfX6 (X = Cl, Br, I) with a vacancy‐ordered cubic double perovskite structure, the halide Cs2HfF6 (CHF), with a hexagonal Bravais lattice, possesses a higher mass density and chemical stability for radiation detection. Luminescence properties and energy transfer mechanisms of rare‐earths‐doped CHF materials are studied here. The structure of CHF is identified as a new type of vacancy‐ordered hexagonal perovskite, with the same type of building blocks of the double perovskite but stacked with single layers. Density‐functional theory calculations reveal a large bandgap of CHF. A broad emission is observed from the pristine CHF host, which is suggested to be associated with self‐trapped excitons (STEs). A series of rare‐earths‐doped materials are designed utilizing the STE emissions, and efficient energy transfers from STEs and Tb3+ to Eu3+ are achieved for tunable emissions. The codoped material shows stable emission under X‐ray irradiation, with 10.2% reduction from its initial emission intensity, associated with possible structural evolution by radiation‐induced deformation of the soft host. The radiation responses of singly and codoped materials are evaluated, and the codoped material is found to be more sensitive to the radiation energy than the singly doped or pristine CHF for radiation detection.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 15, 2022
- Source ID
- 10.1002/adom.202201374
Entities
People
- Bhoj Gautam
- Burak Guzelturk
- C. M. Adhikari
- Menuka Adhikari
- Navadeep Shrivastava
- Rabi Khanal
- Starfari T. Mcclain
- Zhiping Luo
Organizations
- Argonne National Laboratory
- Fayetteville State University
- National Science Foundation
- Oak Ridge National Laboratory
- Office of Basic Energy Sciences
- Office of Science
- United States Department of Defense
- United States Department of Energy