Picosecond Absorption Spectroscopy of Excited States in $\mathrm{Ba}\mathrm{Br}\mathrm{Cl}$ with and without $\mathrm{Eu}$ Dopant and $\mathrm{Au}$ Codopant

Picosecond Absorption Spectroscopy of Excited States in $Ba Br Cl$ with and without $Eu$ Dopant and $Au$ Codopant

Peiyun Li, Sergii Gridin, K. Burak Ucer, Richard T. Williams, Mauro Del Ben, Andrew Canning, Federico Moretti, and Edith Bourret

Phys. Rev. Applied 12, 014035 – Published 19 July 2019

Abstract

We perform picosecond absorption spectroscopy on $Ba Br Cl$ samples that are undoped, doped with europium to make activated scintillators, and codoped with gold (as ${Au Br}_{3}$ in the melt) to increase light yield. The time-resolved measurements provide insights into the effects of interband excitation in $Ba Br Cl$ , including identification of self-trapped-exciton absorption bands, the mechanism of energy transport from the host to the $Eu$ activator, and the effects of $Au$ codoping. First-principles electronic structure calculations of self-trapped-exciton relaxations in $Ba Br Cl$ are presented. $Ba Br Cl$ : $Eu$ , $Au$ is a beneficiary of two material modifications for improvement of performance that have been intensely investigated recently: a mixed-halide solid solution that is further modified by aliovalent codoping.

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Received 1 April 2019
Revised 11 June 2019

DOI:https://doi.org/10.1103/PhysRevApplied.12.014035

Physics Subject Headings (PhySH)

Carrier generation & recombination Color centers Excitons Luminescence

Solid solutions

Scintillators Transient absorption spectroscopy Ultrafast pump-probe spectroscopy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Peiyun Li¹, Sergii Gridin¹, K. Burak Ucer¹, Richard T. Williams ^1,*, Mauro Del Ben², Andrew Canning², Federico Moretti², and Edith Bourret²

¹Department of Physics, Wake Forest University, Winston Salem, North Carolina 27106, USA
²Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA