Insights into the Microstructures and Energy Levels of Pr³⁺-Doped YAlO₃ Scintillating Crystals

Abstract

Trivalent praseodymium (Pr 3+ )-doped materials have been extensively used in high-resolution laser spectroscopy, owing to their outstanding conversion efficiencies of plentiful transitions in the visible laser region. However, to clarify the microstructure and energy transfer mechanism of Pr 3+ -doped host crystals is a challenging topic. In this work, the stable structures of Pr 3+ -doped yttrium orthoaluminate (YAlO 3 ) have been widely searched based on the CALYPSO method. A novel monoclinic structure with the Pm group symmetry is successfully identified. The Pr 3+ impurity can precisely occupy the Y 3+ position and get incorporated into the YAlO 3 (YAP) host crystal with a Pr 3+ concentration of 6.25%. The result of the electronic band structure reveals a 3.62 eV band gap, which suggests a semiconductor character of YAP:Pr. Using our developed well-established parametrization matrix diagonalization (WEPMD) method, we have systematically analyzed the energy level scheme and proposed a set of newly improved parameters. Additionally, the energy transfer mechanism of YAP:Pr is clarified by deciphering the numerical electric dipole and magnetic dipole transitions. The popular red emission at 653 nm is assigned to the transition 3 P 0 → 3 F 2 , while the transition 3 P 0 → 3 H 4 with a large branching ratio is predicted to be a good laser channel. Many promising emission lines for laser actions are also obtained in the visible light region. Our results not only provide important insights into the energy transfer mechanisms of rare-earth ion-doped materials but also pave the way for the implementation of new types of laser devices.

Determining the Hyperfine Structure and Clock Transitions for Kramers Rare-Earth Ions in a Crystal under a Magnetic Field: Beyond Spin Hamiltonian

“…H f and H CF are two dominating interactions in eq and at least twofold degenerate CF levels would be obtained by diagonalization of their matrices on the basis vectors of | LSJM J ⟩. Such two terms, together with the theories of spectral intensities of f–f transitions, are sufficient to explain or design optical spectroscopic properties of RE-doped inorganic materials. , However, the interactions between the 4f electron and nuclear spin, as well as the influence of the external magnetic field on them, should be considered if hybridized electron-nuclear hyperfine sublevels are used in search for ZEFOZ transitions. Hence, the electronic Zeeman term H EZ , magnetic hyperfine interaction H HF , nuclear electric-quadrupole interaction H Q , and nuclear Zeeman term H NZ are added in Hamiltonian H for calculation.…”

“…Such two terms, together with the theories of spectral intensities of f−f transitions, 42 are sufficient to explain or design optical spectroscopic properties of REdoped inorganic materials. 43,44 However, the interactions between the 4f electron and nuclear spin, as well as the influence of the external magnetic field on them, should be considered…”

Adjustable ultraviolet and white light dual emission phosphor Y2Sr(Ga1−yAly)4SiO12:xPr3+ for health lighting

“…4,5 The f-f transition of Pr 3+ ions mainly includes bluegreen emission, green emission, red emission, and deep red emission. [6][7][8][9][10][11] For example, Tian et al reported a tunable polychromatic luminescence performance of Pr 3+ single-doped Y 2 GeO 5 . 12 Li et al reported white-emitting persistent luminescence and trap distribution of Ca 5 Ga 6 O 14 :Pr 3+ phosphors.…”

Theoretical Determination of the Electronic Structures and Energy-Level Splitting for Pr3+-Doped Y2SiO5 Crystals

“…This multisite ligand structure could provide suitable doping sites for many RE ions. The trivalent praseodymium (Pr 3+ ) ion possesses a unique 4f 2 structure and many kinds of potential transition channels in the visible and infrared spectral regions. − When the Pr 3+ ion is doped into Y 2 SiO 5 crystals, an energy-level transition of 3 H 4 → 1 D 2 can be activated . Due to the crystal field interactions of Pr 3+ in the host Y 2 SiO 5 , the 3 H 4 and 1 D 2 states can further split to 9 and 5 Stark levels, respectively.…”