pith. machine review for the scientific record. sign in

arxiv: 2605.10160 · v1 · submitted 2026-05-11 · ❄️ cond-mat.mtrl-sci

Recognition: no theorem link

Ytterbium charge state and stabilization in the Ba(Ca)F₂ host by electron paramagnetic resonance and infrared photoluminescence

David John , Shelja Sharma , Marius Stef , Gabriel Buse , Zden\v{e}k Reme\v{s} , Anna Artemenko , Sergii Chertopalov , Vineet Sikarwar
show 13 more authors
Alan Ma\v{s}l\'ani Jafar Fathi Jakub Pila\v{r} Tom\'a\v{s} Hostinsk\'y Jan Zich Tom\'a\v{s} Mates Brenda Natalia Lopez Nino Michal Hl\'ina Karol Bartosiewicz Marina Konuhova Anatoli Popov J\'an Lan\v{c}ok Maksym Buryi
Authors on Pith no claims yet

Pith reviewed 2026-05-12 03:53 UTC · model grok-4.3

classification ❄️ cond-mat.mtrl-sci
keywords ytterbium dopingfluoride crystalscharge state stabilizationelectron paramagnetic resonanceinfrared photoluminescencedefect formationBaF2CaF2
0
0 comments X

The pith

Host cation identity governs ytterbium charge-state balance and defect-driven optics in BaF2 versus CaF2 crystals, even when long-range structures remain identical.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper compares low-level ytterbium doping in barium fluoride and calcium fluoride single crystals using XRD, XPS, EPR, and infrared photoluminescence. It shows that both hosts keep stable cubic lattices with little change in lattice parameters, yet the choice of cation produces different local environments for the dopant. Barium fluoride favors perturbed Yb3+ sites that increase with doping level and more defect activity, while calcium fluoride keeps mostly unperturbed sites and supports conditions better suited to Yb2+. These host-specific local effects appear in the optical spectra as distinct crystal-field splitting and field broadening, offering a way to tune charge states for photonic uses.

Core claim

A systematic study of 0.05-0.2 mol% ytterbium in BaF2 and CaF2 shows host cation identity controls the stabilization balance between Yb2+ and Yb3+ ions. EPR spectra indicate BaF2 develops more perturbed Yb3+ environments as dopant concentration rises, while CaF2 retains predominantly unperturbed sites. Photothermal deflection and IR photoluminescence measurements further reveal host-dependent optical responses tied to defect mechanisms, establishing a decoupling between long-range structural stability confirmed by XRD and local lattice perturbations.

What carries the argument

Host cation identity (barium versus calcium) as the selector of perturbed versus unperturbed ytterbium sites, measured by EPR line shapes and IR photoluminescence features.

If this is right

  • BaF2 hosts show rising perturbed Yb3+ populations with increasing dopant concentration.
  • CaF2 hosts exhibit clearer crystal-field splitting and broader local-field effects in infrared emission.
  • Long-range cubic phase purity from XRD does not predict the local charge-state preference or defect activity.
  • Host choice can be used to bias toward Yb2+ or Yb3+ stabilization for specific laser or scintillator requirements.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • For applications needing stable divalent ytterbium, calcium fluoride would be the more suitable starting host.
  • Local probes such as EPR remain necessary even when XRD indicates structural equivalence.
  • Surface variations detected by XPS may be secondary effects that do not override the bulk cation-driven trends.

Load-bearing premise

Observed differences in EPR spectra, charge-state ratios, and optical signals arise mainly from host cation identity rather than from doping concentration, surface chemistry, or measurement variations.

What would settle it

Identical EPR spectra, identical Yb2+/Yb3+ ratios from XPS or optical data, and identical defect-related PL bands in BaF2 and CaF2 crystals grown and measured at the same low doping levels under matched conditions would falsify the governing role of host cation identity.

Figures

Figures reproduced from arXiv: 2605.10160 by Alan Ma\v{s}l\'ani, Anatoli Popov, Anna Artemenko, Brenda Natalia Lopez Nino, David John, Gabriel Buse, Jafar Fathi, Jakub Pila\v{r}, J\'an Lan\v{c}ok, Jan Zich, Karol Bartosiewicz, Maksym Buryi, Marina Konuhova, Marius Stef, Michal Hl\'ina, Sergii Chertopalov, Shelja Sharma, Tom\'a\v{s} Hostinsk\'y, Tom\'a\v{s} Mates, Vineet Sikarwar, Zden\v{e}k Reme\v{s}.

Figure 1
Figure 1. Figure 1: Photographs of the cleaved BaF2:YbF3 and CaF2:YbF3 single crystals grown by the vertical Bridgman method for different YbF3 concentrations (0.05, 0.10, and 0.20 mol%) under ambient illumination (A) and UV excitation (B). The use of powdered samples is also standard for X-ray diffraction (XRD) measurements, providing statistically representative structural information. To ensure consistency across different… view at source ↗
read the original abstract

Lanthanide-doped fluorides are promising materials for advanced photonic and quantum applications due to their wide bandgap, low phonon energy, and chemical stability. In this work, we present a systematic comparative study of ytterbium incorporation at low doping levels (0.05--0.2 mol\%) in BaF$_2$ and CaF$_2$ single crystals, focusing on the interplay between host lattice properties, charge-state stabilization, and defect formation mechanisms. Using a combination of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), transmittance, and infrared photoluminescence (IR PL), we explore how host lattice properties affect the stabilization of Yb$^{3+}$ and Yb$^{2+}$ ions. XRD confirmed cubic phase purity and lattice parameter stability in both hosts, while XPS revealed surface chemical composition variations associated with charge-compensating defects and trace impurities. EPR spectra indicated that BaF$_2$ favored perturbed Yb$^{3+}$ environments with increasing dopant levels, while CaF$_2$ maintained predominantly unperturbed sites, suggesting a more favorable ionic match for Yb$^{2+}$. Photothermal deflection spectroscopy (PDS) and IR PL results showed host-specific optical responses, with CaF$_2$ exhibiting crystal-field splitting and broader local field effects. These results reveal a clear decoupling between long-range structural stability and local lattice perturbations, and demonstrate that host cation identity governs the balance between Yb$^{2+}$ and Yb$^{3+}$ stabilization as well as defect-driven optical behavior. This offers valuable insights for optimizing rare-earth-doped fluoride crystals in laser, scintillator, and quantum device applications.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 2 minor

Summary. The manuscript reports a comparative experimental study of Yb incorporation at nominal doping levels of 0.05–0.2 mol% in BaF₂ and CaF₂ single crystals. Using XRD, XPS, EPR, transmittance, photothermal deflection spectroscopy, and IR photoluminescence, the authors observe cubic phase stability in both hosts but host-dependent differences in EPR spectra (perturbed Yb³⁺ sites increasing with dopant in BaF₂ vs. predominantly unperturbed in CaF₂), charge-state balance, and optical responses. They conclude that host cation identity governs Yb²⁺/Yb³⁺ stabilization and defect-driven optical behavior, demonstrating a decoupling between long-range structural order and local lattice perturbations.

Significance. If the attribution to host cation identity can be isolated from confounding factors, the work would offer practical guidance for selecting fluoride hosts to control rare-earth charge states in photonic, scintillator, and quantum applications. The multi-technique approach and focus on low doping levels are positive features, but the current lack of quantitative spectral details and controls limits the strength of the conclusions.

major comments (1)
  1. [Abstract] Abstract and experimental sections: The central claim that host cation identity governs the Yb²⁺/Yb³⁺ balance and defect behavior is not isolated from possible differences in actual incorporated dopant concentrations. Doping is reported only as the nominal range 0.05–0.2 mol% with no evidence of quantification (e.g., ICP-MS, calibrated XPS, or optical absorption) or confirmation that effective Yb levels and compensating defect densities are matched between BaF₂ and CaF₂. Solubility differences could reproduce the observed EPR trend (increasing perturbed sites with dopant in BaF₂) and optical variations without requiring cation identity as the primary cause.
minor comments (2)
  1. [Abstract] The abstract refers to 'crystal-field splitting and broader local field effects' in CaF₂ but provides no numerical values for splitting energies, linewidths, or direct spectral comparisons between hosts.
  2. No error bars, standard deviations, or statistical analysis are mentioned for the EPR intensity trends or PL spectra, making it difficult to assess the robustness of the reported differences.

Simulated Author's Rebuttal

1 responses · 1 unresolved

We thank the referee for the constructive feedback on our manuscript. The concern about isolating host cation effects from possible differences in actual incorporated dopant levels is well taken. We address this point directly below and will make targeted revisions to clarify the use of nominal concentrations while preserving the core conclusions supported by the multi-technique data.

read point-by-point responses

  1. Referee: [Abstract] Abstract and experimental sections: The central claim that host cation identity governs the Yb²⁺/Yb³⁺ balance and defect behavior is not isolated from possible differences in actual incorporated dopant concentrations. Doping is reported only as the nominal range 0.05–0.2 mol% with no evidence of quantification (e.g., ICP-MS, calibrated XPS, or optical absorption) or confirmation that effective Yb levels and compensating defect densities are matched between BaF₂ and CaF₂. Solubility differences could reproduce the observed EPR trend (increasing perturbed sites with dopant in BaF₂) and optical variations without requiring cation identity as the primary cause.

    Authors: We agree that post-growth quantification of actual Yb incorporation would provide stronger isolation of host effects. Our work reports nominal doping levels (0.05–0.2 mol%), as is conventional for Czochralski-grown fluoride crystals where segregation coefficients can lead to minor deviations. All crystals were prepared under identical growth conditions with the same nominal YbF₃ addition. The EPR data reveal a host-specific trend—perturbed Yb³⁺ sites increase systematically with nominal dopant concentration in BaF₂ but remain predominantly unperturbed in CaF₂—consistent with the larger lattice mismatch and lower defect tolerance in the BaF₂ host (Ba²⁺ radius 1.35 Å vs. Ca²⁺ 1.00 Å). XRD confirms cubic phase stability and comparable lattice parameter shifts in both hosts, while the distinct IR PL and PDS responses further differentiate the local environments. Although we cannot exclude solubility variations without additional ICP-MS data, the observed decoupling between long-range order and local perturbations supports host cation identity as the dominant factor. We will revise the abstract and experimental sections to explicitly label concentrations as nominal, add a brief discussion of possible incorporation efficiency differences, and temper the central claim accordingly. revision: partial

standing simulated objections not resolved
  • Quantitative post-growth measurement of actual incorporated Yb concentrations and compensating defect densities (e.g., via ICP-MS or calibrated optical absorption), which was not performed in the original study.

Circularity Check

0 steps flagged

No significant circularity: purely experimental observational study

full rationale

This paper presents an experimental comparative study of Yb incorporation in BaF2 and CaF2 hosts using XRD, XPS, EPR, transmittance, PDS, and IR PL measurements. No mathematical derivations, equations, model predictions, fitted parameters renamed as outputs, or self-citations of uniqueness theorems appear in the text. The central claims about host cation identity governing charge-state balance and defect behavior are drawn directly from the observed spectral differences and phase purity data without any reduction to inputs by construction. The logic chain is self-contained empirical interpretation, with no load-bearing steps that qualify under the enumerated circularity patterns.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

The central claim rests entirely on experimental observations from standard characterization techniques; the abstract mentions no free parameters, mathematical axioms, or newly postulated entities.

pith-pipeline@v0.9.0 · 5739 in / 1159 out tokens · 48988 ms · 2026-05-12T03:53:14.296927+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

58 extracted references · 58 canonical work pages

  1. [1]

    L. Lei, Y. Wang, A. Kuzmin, Y. Hua, J. Zhao, S. Xu, P.N. Prasad, Next generation lanthanide doped nanoscintillators and photon converters, eLight 2 (2022) 17. https://doi.org/10.1186/s43593-022-00024-0

    work page doi:10.1186/s43593-022-00024-0 2022

  2. [2]

    W. Xu, S. Zhang, A. Wei, D. Deng, S. Zhou, S. Xu, L. Lei, Advancing Multi‐Optical Performances in Lanthanide‐Doped Fluoride Core@Shell Nanoarchitectures by Minimizing Cation Intermixing, Adv Funct Materials 35 (2025) 2415815. https://doi.org/10.1002/adfm.202415815

    work page doi:10.1002/adfm.202415815 2025

  3. [3]

    L. Wang, Y. Li, Controlled Synthesis and Luminescence of Lanthanide Doped NaYF4 Nanocrystals, Chem. Mater. 19 (2007) 727-734. https://doi.org/10.1021/cm061887m

    work page doi:10.1021/cm061887m 2007

  4. [4]

    H. Yang, A. Zhang, H. Guo, D. Li, S. Xu, L. Lei, Enhancing upconversion via constructing local energy clusters in lanthanide-doped fluoride nanoparticles, J. Mater. Chem. C 11 (2023) 12915- 12921. https://doi.org/10.1039/D3TC02494F

    work page doi:10.1039/d3tc02494f 2023

  5. [5]

    Liang, F

    Y.-J. Liang, F. Liu, Y.-F. Chen, X.-J. Wang, K.-N. Sun, Z. Pan, New function of the Yb3+ ion as an efficient emitter of persistent luminescence in the short-wave infrared, Light Sci Appl 5 (2016) e16124-e16124. https://doi.org/10.1038/lsa.2016.124

    work page doi:10.1038/lsa.2016.124 2016

  6. [6]

    Y. Tai, H. Wang, H. Wang, J. Bai, Near-infrared down-conversion in Er3+ -Yb3+ co-doped transparent nanostructured glass ceramics for crystalline silicon solar cells, RSC Adv. 6 (2016) 4085-4089. https://doi.org/10.1039/C5RA25800F

    work page doi:10.1039/c5ra25800f 2016

  7. [7]

    Strohhöfer, A

    C. Strohhöfer, A. Polman, Absorption and emission spectroscopy in Er3+-Yb3+ doped aluminum oxide waveguides, Optical Materials 21 (2003) 705-712. https://doi.org/10.1016/S0925-3467(02)00056-3

    work page doi:10.1016/s0925-3467(02)00056-3 2003

  8. [8]

    Kye, C.-J

    Y.-H. Kye, C.-J. Yu, U.-G. Jong, C.-N. Sin, W. Qin, Defect properties in Yb3+ -doped CaF2 from first-principles calculations: a route to defect engineering for up- and down-conversion photoluminescence, J. Mater. Chem. C 7 (2019) 15148-15152. https://doi.org/10.1039/C9TC04786G

    work page doi:10.1039/c9tc04786g 2019

  9. [9]

    Nalumaga, J.J

    H. Nalumaga, J.J. Schuyt, R.D. Breukers, G.V.M. Williams, Radiation-induced changes in the photoluminescence properties of NaMgF3:Yb nanoparticles: Yb3+ → Yb2+ valence conversion and oxygen-impurity charge transfer, Materials Research Bulletin 145 (2022) 111562. https://doi.org/10.1016/j.materresbull.2021.111562

    work page doi:10.1016/j.materresbull.2021.111562 2022

  10. [10]

    Balabhadra, M.F

    S. Balabhadra, M.F. Reid, V. Golovko, J.-P.R. Wells, Absorption spectra, defect site distribution and upconversion excitation spectra of CaF2/SrF2/BaF2:Yb3+:Er3+ nanoparticles, Journal of Alloys and Compounds 834 (2020) 155165. https://doi.org/10.1016/j.jallcom.2020.155165

    work page doi:10.1016/j.jallcom.2020.155165 2020

  11. [11]

    Shanker, S.C

    J. Shanker, S.C. Agrawal, Electronic polarizabilities and sizes of ions in alkaline earth halides and alkali chalcogenides, Journal of Physics and Chemistry of Solids 41 (1980) 209-213. https://doi.org/10.1016/0022-3697(80)90187-0

    work page doi:10.1016/0022-3697(80)90187-0 1980

  12. [12]

    M. Stef, I. Nicoara, D. Vizman, Distribution of Yb3+ and Yb2+ Ions along YbF3 ‐Doped BaF2 Crystals, Crystal Research and Technology 53 (2018) 1800186. https://doi.org/10.1002/crat.201800186

    work page doi:10.1002/crat.201800186 2018

  13. [13]

    Kaczmarek, T

    S.M. Kaczmarek, T. Tsuboi, M. Ito, G. Boulon, G. Leniec, Optical study of Yb3+ /Yb2+ conversion in CaF2 crystals, J. Phys.: Condens. Matter 17 (2005) 3771-3786. https://doi.org/10.1088/0953-8984/17/25/005

    work page doi:10.1088/0953-8984/17/25/005 2005

  14. [14]

    Barandiarán, L

    Z. Barandiarán, L. Seijo, Intervalence charge transfer luminescence: Interplay between anomalous and 5 d − 4 f emissions in Yb-doped fluorite-type crystals, The Journal of Chemical Physics 141 (2014) 234704. https://doi.org/10.1063/1.4902759

    work page doi:10.1063/1.4902759 2014

  15. [15]

    d’Acapito, S

    F. d’Acapito, S. Pelli-Cresi, W. Blanc, M. Benabdesselam, F. Mady, P. Gredin, M. Mortier, The incorporation site of Er in nanosized CaF2, J. Phys.: Condens. Matter 28 (2016) 485301. https://doi.org/10.1088/0953-8984/28/48/485301

    work page doi:10.1088/0953-8984/28/48/485301 2016

  16. [16]

    Nelson, T

    A.J. Nelson, T. Van Buuren, C. Bostedt, K.I. Schaffers, L.J. Terminello, M. Engelhard, D. Baer, Electronic structure of ytterbium-doped strontium fluoroapatite: Photoemission and photoabsorption investigation, Journal of Applied Physics 91 (2002) 5135-5140. https://doi.org/10.1063/1.1459601

    work page doi:10.1063/1.1459601 2002

  17. [17]

    Hayes, A.M

    W. Hayes, A.M. Stoneham, Defects and defect processes in nonmetallic solids, Dover edition, Dover Publications, Mineola, N.Y, 2004

    work page 2004

  18. [18]

    Henderson, G.F

    B. Henderson, G.F. Imbusch, Optical spectroscopy of inorganic solids, Clarendon Press ; Oxford University Press, Oxford [Oxfordshire] : New York, 1989

    work page 1989

  19. [19]

    Itoh, A.M

    N. Itoh, A.M. Stoneham, Materials modification by electronic excitation, Radiation Effects and Defects in Solids 155 (2001) 277-290. https://doi.org/10.1080/10420150108214126

    work page doi:10.1080/10420150108214126 2001

  20. [20]

    Blasse, B.C

    G. Blasse, B.C. Grabmaier, Luminescent Materials, Springer Berlin Heidelberg, Berlin, Heidelberg, 1994. https://doi.org/10.1007/978-3-642-79017-1

    work page doi:10.1007/978-3-642-79017-1 1994

  21. [21]

    Laguta, M

    V.V. Laguta, M. Buryi, M. Nikl, J. Rosa, S. Zazubovich, Hole capture in PbWO4:Mo,La(Y) scintillator crystals, Physical Review B - Condensed Matter and Materials Physics 83 (2011). https://doi.org/10.1103/PhysRevB.83.094123

    work page doi:10.1103/physrevb.83.094123 2011

  22. [22]

    Erickson, M.J

    C.S. Erickson, M.J. Crane, T.J. Milstein, D.R. Gamelin, Photoluminescence Saturation in Quantum-Cutting Yb3+ -Doped CsPb(Cl 1- x Br x )3 Perovskite Nanocrystals: Implications for Solar Downconversion, J. Phys. Chem. C 123 (2019) 12474-12484. https://doi.org/10.1021/acs.jpcc.9b01296

    work page doi:10.1021/acs.jpcc.9b01296 2019

  23. [23]

    Ishii, T

    A. Ishii, T. Miyasaka, Sensitized Yb3+ Luminescence in CsPbCl3 Film for Highly Efficient Near‐ Infrared Light‐Emitting Diodes, Advanced Science 7 (2020) 1903142. https://doi.org/10.1002/advs.201903142

    work page doi:10.1002/advs.201903142 2020

  24. [24]

    Zhang, A

    C. Zhang, A. Zhang, T. Liu, L. Zhou, J. Zheng, Y. Zuo, Y. He, J. Li, A facile method for preparing Yb3+ -doped perovskite nanocrystals with ultra-stable near-infrared light emission, RSC Adv. 10 (2020) 17635-17641. https://doi.org/10.1039/D0RA01897J

    work page doi:10.1039/d0ra01897j 2020

  25. [25]

    Procházková, V

    L. Procházková, V. Vaněček, V. Čuba, R. Pjatkan, R. Martinez-Turtos, I. Jakubec, M. Buryi, S. Omelkov, E. Auffray, P. Lecoq, E. Mihóková, M. Nikl, Core-shell ZnO:Ga-SiO2 nanocrystals: Limiting particle agglomeration and increasing luminescence: Via surface defect passivation, RSC Advances 9 (2019) 28946-28952. https://doi.org/10.1039/c9ra04421c

    work page doi:10.1039/c9ra04421c 2019

  26. [26]

    Pusdekar, N

    A. Pusdekar, N. Ugemuge, C. Gayner, R.A. Nafdey, S. Moharil, Energy transfer dynamics in Na5Y(WO4)4: Ln3+(Ln=Nd, Er, Yb) Phosphors, Materials Research Bulletin 199 (2026) 114065. https://doi.org/10.1016/j.materresbull.2026.114065

    work page doi:10.1016/j.materresbull.2026.114065 2026

  27. [27]

    Bünzli, S.V

    J.-C.G. Bünzli, S.V. Eliseeva, Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion, Journal of Rare Earths 28 (2010) 824-842. https://doi.org/10.1016/S1002-0721(09)60208-8

    work page doi:10.1016/s1002-0721(09)60208-8 2010

  28. [28]

    Petit, P

    V. Petit, P. Camy, J.-L. Doualan, X. Portier, R. Moncorgé, Spectroscopy of Yb 3 + : CaF 2 : From isolated centers to clusters, Phys. Rev. B 78 (2008) 085131. https://doi.org/10.1103/PhysRevB.78.085131

    work page doi:10.1103/physrevb.78.085131 2008

  29. [29]

    Zhang, Z

    S. Zhang, Z. Song, F. Zhao, S. Liu, H. Cai, S. Wang, Q. Liu, Selecting nitride host for Yb3+ toward near-infrared emission with low-energy charge transfer band, Journal of Rare Earths 39 (2021) 1484-1491. https://doi.org/10.1016/j.jre.2021.05.012

    work page doi:10.1016/j.jre.2021.05.012 2021

  30. [30]

    J. Tan, N. Hu, X. Li, H. Zhou, Z. Li, P. Zhang, Z. Chen, Yb:YGG, crystal growth, concentration dependent, spectroscopy and the luminescence mechanisms, Infrared Physics & Technology 156 (2026) 106555. https://doi.org/10.1016/j.infrared.2026.106555

    work page doi:10.1016/j.infrared.2026.106555 2026

  31. [31]

    Babin, M

    V. Babin, M. Buryi, V. Chlan, Y. Fomichov, K. Kamada, V.V. Laguta, M. Nikl, J. Pejchal, H. Štěpánková, A. Yoshikawa, Yu. Zagorodniy, S. Zazubovich, Influence of gallium content on Ga3+ position and photo- and thermally stimulated luminescence in Ce3+-doped multicomponent (Y,Lu)3GaxAl5-xO12 garnets, Journal of Luminescence 200 (2018) 141-150. https://doi.o...

    work page doi:10.1016/j.jlumin.2018.04.013 2018

  32. [32]

    Bünzli, Lanthanide Luminescence for Biomedical Analyses and Imaging, Chem

    J.-C.G. Bünzli, Lanthanide Luminescence for Biomedical Analyses and Imaging, Chem. Rev. 110 (2010) 2729-2755. https://doi.org/10.1021/cr900362e

    work page doi:10.1021/cr900362e 2010

  33. [33]

    Sontakke, J

    A.D. Sontakke, J. Ueda, J. Xu, K. Asami, M. Katayama, Y. Inada, S. Tanabe, A Comparison on Ce3+ Luminescence in Borate Glass and YAG Ceramic: Understanding the Role of Host’s Characteristics, J. Phys. Chem. C 120 (2016) 17683-17691. https://doi.org/10.1021/acs.jpcc.6b04159

    work page doi:10.1021/acs.jpcc.6b04159 2016

  34. [34]

    Venkata Krishnaiah, C.K

    K. Venkata Krishnaiah, C.K. Jayasankar, V. Venkatramu, S.F. Leόn-Luis, V. Lavín, S. Chaurasia, L.J. Dhareshwar, Optical properties of Yb3+ ions in fluorophosphate glasses for 1.0 μm solid-state infrared lasers, Appl. Phys. B 113 (2013) 527-535. https://doi.org/10.1007/s00340-013-5502-6

    work page doi:10.1007/s00340-013-5502-6 2013

  35. [35]

    Barua, E.H

    P. Barua, E.H. Sekiya, K. Saito, A.J. Ikushima, Influences of Yb3+ ion concentration on the spectroscopic properties of silica glass, Journal of Non-Crystalline Solids 354 (2008) 4760-4764. https://doi.org/10.1016/j.jnoncrysol.2008.04.020

    work page doi:10.1016/j.jnoncrysol.2008.04.020 2008

  36. [36]

    Hongisto, A

    M. Hongisto, A. Veber, N.G. Boetti, S. Danto, V. Jubera, L. Petit, Transparent Yb3+ doped phosphate glass-ceramics, Ceramics International 46 (2020) 26317-26325. https://doi.org/10.1016/j.ceramint.2020.01.121

    work page doi:10.1016/j.ceramint.2020.01.121 2020

  37. [37]

    Schornig, M

    C. Schornig, M. Stef, G. Buse, M. Poienar, P. Veber, D. Vizman, Spectroscopic Properties of TmF3-Doped CaF2 Crystals, Materials 17 (2024) 4965. https://doi.org/10.3390/ma17204965

    work page doi:10.3390/ma17204965 2024

  38. [38]

    M. Stef, C. Schornig, G. Buse, M. Poienar, P. Veber, D. Vizman, Spectroscopic analysis and Judd-Ofelt modelling of Tm3+ -doped BaF2 crystals, Optical Materials 169 (2026) 117689. https://doi.org/10.1016/j.optmat.2025.117689

    work page doi:10.1016/j.optmat.2025.117689 2026

  39. [39]

    Bottomonia in quark –antiquark confining potential,

    Z. Remeš, Š. Remeš, N. Neykova, N. Jain, R.K. Sharma, J. Holovský, E. Ukraintsev, J. Kuliček, B. Rezek, H.S. Hsu, Optical, electrical and surface properties of bare and Al-doped nanocrystalline ZnO (AZO) thin films grown by pulsed laser deposition (PLD) on commercial interdigital electrodes (IDE), Phys. Scr. 100 (2025) 115910. https://doi.org/10.1088/1402...

    work page doi:10.1088/1402- 2025

  40. [40]

    Stoll, A

    S. Stoll, A. Schweiger, EasySpin, a comprehensive software package for spectral simulation and analysis in EPR, J. Magn. Reson. 178 (2006) 42-55. https://doi.org/10.1016/j.jmr.2005.08.013

    work page doi:10.1016/j.jmr.2005.08.013 2006

  41. [41]

    M. 21. J.J.F.,. Stickle, W.F.,. Sobol, P.E.,. Bomben, K.D. (eds.)., Handbook of X-ray Photoelectron Spectroscopy, Physical Electronics, Inc., Minnesota, n.d

    work page

  42. [42]

    H. Qiu, P. Yang, J. Dong, P. Deng, J. Xu, W. Chen, The influence of Yb concentration on laser crystal Yb:YAG, Materials Letters 55 (2002) 1-7. https://doi.org/10.1016/S0167- 577X(01)00608-5

    work page doi:10.1016/s0167- 2002

  43. [43]

    C. Wu, X. Yu, W. Zhu, K. Han, Z. Tian, Q. He, P. Zhao, Bi3+-enhanced upconversion luminescence and high-sensitivity optical thermometry in Er3+/Yb3+ co-doped Cs2NaYCl6 double perovskite crystals, Ceramics International 51 (2025) 36170-36181. https://doi.org/10.1016/j.ceramint.2025.05.338

    work page doi:10.1016/j.ceramint.2025.05.338 2025

  44. [44]

    C. Zhao, C. Wang, J. Song, H. Wang, Z. Yu, J. Wang, Z. Zhao, X. Li, J. Liu, K. Lin, Z. Wang, A. Neogi, Ultra‐Efficient, Broadband‐Excitable NIR Emission in Lead‐Free Cs2 NaYbCl6 via Cl → Yb Charge Transfer and Cr3+ Sensitization, Advanced Optical Materials 13 (2025) e01549. https://doi.org/10.1002/adom.202501549

    work page doi:10.1002/adom.202501549 2025

  45. [45]

    Buryi, V

    M. Buryi, V. Babin, V. Laguta, Y. Yokota, H. Sato, A. Yoshikawa, J. Pejchal, M. Nikl, Undoped and Eu, Na co-doped LiCaAlF6 scintillation crystals: Paramagnetic centers, charge trapping and energy transfer properties, Journal of Alloys and Compounds 858 (2021) 158297. https://doi.org/10.1016/j.jallcom.2020.158297

    work page doi:10.1016/j.jallcom.2020.158297 2021

  46. [46]

    Shannon, Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides, Acta Cryst A 32 (1976) 751-767

    R.D. Shannon, Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides, Acta Cryst A 32 (1976) 751-767. https://doi.org/10.1107/S0567739476001551

    work page doi:10.1107/s0567739476001551 1976

  47. [47]

    Fuller, Nuclear spins and moments, J

    G.H. Fuller, Nuclear spins and moments, J. Phys. Chem. Ref. Data 1976 (n.d.) 835-1092

    work page 1976

  48. [48]

    Wertz, J.R

    J.E. Wertz, J.R. Bolton, Electron spin resonance: elementary theory and practical applications, McGraw-Hill, New York, 1972

    work page 1972

  49. [49]

    Abragam, B

    A. Abragam, B. Bleaney, Electron paramagnetic resonance of transition ions, Oxford University Press, Oxford, 2012

    work page 2012

  50. [50]

    Cotton, Chemical applications of group theory, 3rd ed, Wiley, New York, 1990

    F.A. Cotton, Chemical applications of group theory, 3rd ed, Wiley, New York, 1990

    work page 1990

  51. [51]

    Thomas, W.J

    M.E. Thomas, W.J. Tropf, Barium Fluoride (BaF2), in: Handbook of Optical Constants of Solids, Elsevier, 1997: pp. 683-699. https://doi.org/10.1016/B978-012544415-6.50125-4

    work page doi:10.1016/b978-012544415-6.50125-4 1997

  52. [52]

    Morris, T

    E. Morris, T. Groy, K. Leinenweber, Crystal structure and bonding in the high-pressure form of fluorite (CaF2), Journal of Physics and Chemistry of Solids 62 (2001) 1117-1122. https://doi.org/10.1016/S0022-3697(00)00291-2

    work page doi:10.1016/s0022-3697(00)00291-2 2001

  53. [53]

    Nicoara, L

    I. Nicoara, L. Lighezan, M. Enculescu, I. Enculescu, Optical spectroscopy of Yb2+ ions in YbF3-doped CaF2 crystals, Journal of Crystal Growth 310 (2008) 2026-2032. https://doi.org/10.1016/j.jcrysgro.2007.11.183

    work page doi:10.1016/j.jcrysgro.2007.11.183 2008

  54. [54]

    Matzke, Fluorine self-diffusion in CaF2 and BaF2, J Mater Sci 5 (1970) 831-836

    Hj. Matzke, Fluorine self-diffusion in CaF2 and BaF2, J Mater Sci 5 (1970) 831-836. https://doi.org/10.1007/BF00574851

    work page doi:10.1007/bf00574851 1970

  55. [55]

    Nicoara, M

    I. Nicoara, M. Stef, Charge compensating defects study of YbF‐doped BaF crystals using dielectric loss, Physica Status Solidi (b) 253 (2016) 397-403. https://doi.org/10.1002/pssb.201552507

    work page doi:10.1002/pssb.201552507 2016

  56. [56]

    Poole, Electron spin resonance: a comprehensive treatise on experimental techniques, Dover Publications, Mineola, N.Y, 1996

    C.P. Poole, Electron spin resonance: a comprehensive treatise on experimental techniques, Dover Publications, Mineola, N.Y, 1996

    work page 1996

  57. [57]

    S. Zhao, Z. Xu, L. Wang, S. Wageh, Influence of Yb3+ concentration on the upconversion luminescence of oxyfluoride material doped with Er3+, Sci. China Phys. Mech. Astron. 53 (2010) 310-314. https://doi.org/10.1007/s11433-010-0117-y

    work page doi:10.1007/s11433-010-0117-y 2010

  58. [58]

    Zhang, J

    J. Zhang, J. Heo, 980 nm upconversion luminescence from oxy-fluoride glasses and glass- ceramics doped with Yb3+and Er3+ ions, Journal of Non-Crystalline Solids 383 (2014) 188-191. https://doi.org/10.1016/j.jnoncrysol.2013.04.026

    work page doi:10.1016/j.jnoncrysol.2013.04.026 2014