Photoinduced dynamics to photoluminescence in Ln³⁺ (Ln = Ce, Pr) doped β-NaYF₄ nanocrystals computed in basis of non-collinear spin DFT with spin-orbit coupling

ABSTRACT

In this work, non-collinear spin DFT + U approaches with spin-orbit coupling (SOC) are applied to Ln³⁺ doped β-NaYF₄ (Ln = Ce, Pr) nanocrystals in Vienna ab initio Simulation Package taking into account unpaired spin configurations using the Perdew–Burke–Ernzerhof functional in a plane wave basis set. The calculated absorption spectra from non-collinear spin DFT + U approaches are compared with that from spin-polarised DFT + U approaches. The spectral difference indicates the importance of spin–flip transitions of Ln³⁺ ions. Suite of codes for nonadiabatic dynamics has been developed for 2-component spinor orbitals. On-the-fly nonadiabatic coupling calculations provide transition probabilities facilitated by nuclear motion. Relaxation rates of electrons and holes are calculated using Redfield theory in the reduced density matrix formalism cast in the basis of non-collinear spin DFT + U with SOC. The emission spectra are calculated using the time-integrated method along the excited state trajectories based on nonadiabatic couplings.

KEYWORDS:

• Lanthanides
• spin-orbit coupling
• nonadiabatic dynamics
• photoluminescence
• non-collinear spin density functional theory

Acknowledgments

This research has been supported by NSF CHE-1413614 for methods development. Authors thank DOE BES NERSC facility for computational resources, allocation award #91202, ‘Computational Modeling of Photo-catalysis and Photo-induced Charge Transfer Dynamics on Surfaces’ supported by the Office of Science of the DOE under contract no. DE-AC02-05CH11231. Talgat M. Inerbaev thanks the Center for Computational Materials Science, Institute for Materials Research, Tohoku University (Sendai, Japan) for their continuous support of the SR16000 M1 supercomputing system. The calculations were partially performed at supercomputer cluster ‘Cherry’ provided by the Materials Modeling and Development Laboratory at NUST ‘MISIS’ (supported via the Grant from the Ministry of Education and Science of the Russian Federation No. 14.Y26.31.0005). The authors would like to thank Douglas Jennewein for support and maintaining the High-Performance Computing system at the University of South Dakota. Gratefulness is also extended to Ge Yao, Stephanie Jensen, Wendi Sapp, Adam Erck, Brendon Disrud and Bakhtyor Rasulev for collective discussion and editing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Division of Chemistry, NSF [grant number CHE-1413614]; Office of Science of the DOE [contract number DE-AC02-05CH11231]; Ministry of Education and Science of the Russian Federation [grant number 14.Y26.31.0005].