Rationalizing the structural changes and spectra of manganese and their temperature dependence in a series of garnets with first-principles calculations

Mn ions‐activated Gd3(Al,Ga)5O12 garnet solid‐solution ceramics: Cation substitution for dual wavelength red‐emission

“…According to the study reported by Kück et al., 46 the excitation band of YAG:Mn 3+ , GSGG:Mn 3+ , YSGG:Mn 3+ , GGG:Mn 3+ , YGG:Mn 3+ crystals were dominated by a strong absorption band at green region with a maximum around 510 nm. Recently, the energy of the spin‐allowed excitation 5 E′ → 5 T 2 of YAG:Mn 3+ was calculated to be 2.37 eV (523 nm) using first‐principles calculations 47 . This conclusion was in good agreement with our experimental results (527 nm).…”

“…Recently, the energy of the spin-allowed excitation 5 E′ → 5T 2 of YAG:Mn 3+ was calculated to be 2.37 eV (523 nm) using first-principles calculations. 47 This conclusion was in good agreement with our experimental results (527 nm). The concentration of Mn 3+ ions decreased with increasing Ga 3+ contents owing to the mismatch of ionic radius between Mn 3+ and Ga 3+ ions.…”

“…The concentration of Mn 3+ ions decreased with increasing Ga 3+ contents owing to the mismatch of ionic radius between Mn 3+ and Ga 3+ ions. Moreover, as reported by Duan et al, 47 the emission energies ( 5T 2 → 5 E′) of Mn 3+ doped YAG host was also calculated to be 2.06 eV (602 nm), and the experimental emission energy value was 620 nm. Additionally, the broad red-emission band of Mn 3+ could also be identified under 266-or 275-nm excitation, which was corresponding to the charge transfer of Mn 3+ -O 2− .…”

Elucidating the Multisite and Multivalence Nature of Mn Ions in Solids and Predicting Their Optical Transition Properties: A Case Study on a Series of Garnet Hosts

“…13,14 Besides, as an intermediate valence state, Mn 3+ has shown strong Jahn−Teller distortion, which is critically important in determining its site occupancy and magnetic order. We show in our recent work 15 and here the importance of Mn 3+ in luminescent materials, which has seldom been considered previously, and the unique luminescence properties, such as temperature-dependent red to NIR luminescence and the quenching of photoluminescence, have been explored. 15,16 The abundant site occupancy and the overlapped spectra of Mn 4+ , Mn 3+ , and Mn 2+ enhance the difficulty of luminescence identification, and the multisite occupancy and multivalence states of Mn ions enhance the difficulty of material design and optimization.…”

Angular Jahn–Teller Effect and Photoluminescence of the Tetrahedral Coordinated Mn2+ Activators in Solids–A First-Principles Study

“…The transition metal molecules or clusters have been modeled by quantum chemistry calculations, − and various improvements have been reported to deal with the problem induced by carving a finite cluster from the bulk, which often involves cutting metal-linker bonds, and may lead to charged clusters and truncation artifacts, and thus the results may depend sensitively on the choice of the cluster. − On the other hand, the calculations based on density functional theory with the periodic supercell formalism have been successfully applied in the study of the stabilization and luminescence of activator centers, such as Ce 3+ , Bi 3+ , Mn 3+ , and Mn 4+ . For the excited states of the multielectron d 5 system in the framework of density functional theory, the spin contamination is a problem in particular to overcome, , which could especially be challenging for the excited states in tetrahedral coordinations due to the much weaker ligand-field splitting than the cases of octahedral or cubic coordinations.…”