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Modern Solid State NMR Strategies for the Structural Characterization of Disordered Materials

Modern Solid State NMR Strategies for the Structural Characterization of Disordered Materials. Hellmut Eckert Instituto da Física S ã o Carlos Universidade de S ã o Paulo. Disordered States of Matter. Non-Stoichiometric Compounds Plastic Crystals Glasses, Gels, Ceramics Nanocomposites.

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Modern Solid State NMR Strategies for the Structural Characterization of Disordered Materials

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  1. Modern Solid State NMR Strategies for the Structural Characterization of Disordered Materials Hellmut Eckert Instituto da Física São Carlos Universidade de São Paulo

  2. Disordered States of Matter Non-Stoichiometric Compounds Plastic Crystals Glasses, Gels, Ceramics Nanocomposites Composition Preparation, Processing Structure Dynamics Properties

  3. O estado vítreo: aspectos termodinâmicos gás líquido transiçãovítrea vidro cristal Entalpia, volume Temperatura

  4. Distance distributions in states of matter

  5. Network formers: SiO2,B2O3,P2O5,Al2O3 Network modifiers: alkaline, alkaline-earth or silver oxides Ion ConductingGlasses

  6. network modifier network former B O M directly bonded neighbors 200-300 pm Coordination numbers and symmetries Site quantification Short Range Order

  7. B, Si, P O Li-Cs Spatial distribution of modifiers 300-600 pm Network former-network modifier correlation Network former connectivity Medium-range Order in Glasses

  8. Nano- and Microstructure • Chemical Segregation, • Phase Separation, • Nucleation/growth > 1nm

  9. Solid State NMR B0 E Element selective Locally selective hn Inherently quantitative H = HZ + HD + HCS + HQ experimentelly flexible selective - averaging Distances Bonding geometry

  10. H = HZ + HD + HCS + HQ Magic AngleSpinning - MAS zr B0 Haniso= A . {3 cos2 q – 1} rot θ iso 2nd. Interações Dipolares Anisotropia de Desvio Químico - CSA Interações Quadrupolares de Primeira Ordem

  11. Current Research Agenda H. Eckert eckert@ifsc.usp.br NMR Methods Glass Li Ion Battery Optical Catalysts Development Science Components Materials Biomaterials SSNMR, ESR Structure Electrode Luminescent FLP, Zeolite Dipolar Dynamics, Electrolytes, Ceramics, Nanocomposites Techniques Sol-Gel Ceramics Hybrids Bioceramics • Support • Industry: Corning, Schott, Ivoclar, Nippon Glass • DFG, DFG-SFB, IRTG, BMBF • CNPq Universal, FAPESP, CEPID, CNPq- 1B

  12. Mixed Network Former Effect In Ion-Conducting Glasses In a glass system with fixed network modifier content: How do the physical properties change when we vary the network former composition ? Often these changes are non-linear, requiring fundamental understanding on a structural basis

  13. Mixed network former effect in the (M2O)0.33[(P2O5)1-x(B2O3)x ]0.67 – System (M = Li, K, Cs): Glass Transition Temperatures

  14. Mixed network former effect in the (M2O)0.33[(P2O5)1-x(B2O3)x ]0.67 – System (M = Li, K, Cs) DC- conductivity (300 K) Activation Energies

  15. Dynamic characterization by static 7Li NMR Single Network former Mixed network former M. Storek, R. Böhmer, S. W. Martin, D. Larink, H. Eckert, J. Chem. Phys. 2012

  16. Structural Issues Regarding the Mixed-Network Former Effect • Network former speciations • Coordination polyhedra • Types of anionic and neutral species present • Connectivity distributions • Random Linkages ? • Connectivity Preferences ? • Clustering/Phase separation ? • Competition for the network modifier • Proportional sharing vs. preferential attraction • Relation to physical properties

  17. SOLID STATE NMR CHARACTERIZATION B(3) B(4) P(1) P(2) P(3) 11B 31P D. Larink, H. Eckert, M. Reichert, S.W. Martin, J. Phys. Chem. 126, 26162-26176 (2012)

  18. Structural speciation in the (K2O)0.33[(P2O5)1-x(B2O3)x ]0.67 – system 0 < x < 0.5: P(2) units successively replaced by B(4) units 0.5 < x 1.0: P(3) units successively replaced by B(3) units

  19. Tg-value and network connectedness 0 < x < 0.5: P(2) units successively replaced by B(4) units 0.5 < x 1.0: P(3) units successively replaced by B(3) units Glass transition temperature number of bridging oxygen per network former unit

  20. 11B- MAS –NMR Spectra of Borophosphate Glasses 50% Ag2O * x P2O5 * (50%-x) B2O3 BO4 BO3 Connectivity with phosphorus ??

  21. Modulation of HD under Sample Rotation + I - Tr S + + Tr I-channel p pulse Magic- Angle Spinning (MAS) 31P Rotational Echo Double Resonance (REDOR) 11B

  22. p p/2 2 0 1 3 4 DS = S0 p/2 p [ Tr ] REDOR Pulse Sequence 11B 31P - S S0 S0 11B 31P

  23. Site Connectivities in Borophosphate Glasses: 11B {31P}-REDOR on 50% Ag2O - 25% B2O3 - 25% P2O5 difference spin echo with dephasing BO4 BO3 spin echo

  24. REDOR Pulse Sequence p p/2 2 0 1 3 4 DS S0 p/2 p [ Tr ] 11B 31P depends on: 11B strength of interaction (# neighbors, distance) 31P dipolar evolution time N . Tr

  25. Analysis of REDOR Curves in Glasses .

  26. meas 2 M = 15.8 ± 0.2 kHz 2 theo 2 M = 18.48 kHz 1.0 2 0.8 0 -S)/S 0.6 0 (S 0.4 0.2 Measurement Simulation 0.0 0.0000 0.0005 0.0010 0.0015 0.0020 NT (s) r 11B{31P} REDOR of Crystalline BPO4 .

  27. Network connectivity: 11B{31P} REDOR DS/So = 4/3p M2 (N.Tr)2 M2 ~ Srij-6 M2 = 4-5 . 106 rad2/s2 per B-O-P linkage No B(3)-O-P connectivity

  28. Network connectivity via O-1s XPS: P-O-P NBO B-O-B P-O-B Constant linewidth Peak position changing monotonically Areas consistent with composition Model compound validation B-O-B P-O-B NBO P-O-P Binding energy [eV]

  29. Quantification of network connectivity: Chemical ordering scenario maximized B(4)-O-P Connectivity no B(3)-O-P Connectivity no B(4)-O- B(4) Connectivity; no P(2)2B units

  30. Structure-property correlations in the (M2O)0.33[(P2O5)1-x(B2O3)x ]0.67 – system Speciation electrical conductivities Charge delocalization near P31B and B40P units creates shallow Coulomb traps, favoring ionic mobility

  31. Summary Solid State NMR as a tool in complex phosphate glasses • Quantification of Mixed Network Former Effects • Site Quantifications • Connectivity distributions • Network modifier sharing • Structure/Property correlations: Tg, s • Tendency for heteratomic linkages decreases: • Borophosphate -> Germanophosphate • ->Tellurophosphate -> Thioborophosphate • Other systems studied: • Alumoborate, Alumophosphate, • Alumophosphosilicat

  32. Optical Glasses and Ceramics Waveguides, NLO-materials, Matrices for RE dopants for potential laser applications • Aluminophosphate or -borate matrices • Rare-Earth (RE) ion emitters embedded in a glassy or ceramic environment • Luminescence intensity (excited state lifetime, quantum yield) critically controlled by RE local environment and spatial distribution Fundamental Problem:NMR of fluorescent rare earthions isimpossible due totheir strong f-electronparamagnetism

  33. Structural Magnetic Resonance Approaches • NMR analysis of diamagnetic • mimics to RE species. • 45Sc, 89Y-NMR • NMR analysis of diamagnetic • mimics to RE species. • ´45Sc, 89Y-NMR 2. NMR analysis of paramagnetic effects on host constituent nuclei: HZ and T1 2. NMR analysis of paramagnetic effects on host constituent nuclei: HZ and T1 3. EPR analysis of electron-nuclear dipolar couplings (studied by ESEEM) = RE3+ = Sc3+, Y3+

  34. 1. The Diamagnetic Mimic Approach NMR properties of the isotopes nuclide 45Sc 89Y 139La 171Yb 175Lu Spin 7/2 1/2 7/2 1/2 7/2 % abundance 100 100 99.9 14.3 97.4 Q/1028m2 0.22 0 0.2 0 2.8 n/MHz (11.7T) 121 24.5 71.2 88.0 57.2

  35. 89Y MAS NMR of yttrium aluminoborate glasses and crystalline model compounds 20(Al2O3)-20Y2O3-60B2O3

  36. 11B MAS NMR of 40-y(Al2O3)-yY2O3-60B2O3 (10  y  25) BO33- (orthoborates) BO3- (metaborates) BO32- (pyroborates) Prior to crystallization BO4 H. Deters, A. S. S. de Camargo, H. Eckert, et al. J. Phys. Chem. C 113, 16216 (2009)

  37. 11B MAS NMR of vitroceramics in the 40-y(Al2O3)-yY2O3-60B2O3 system (10  y  25) No evidence of meta- or pyroborate groups in the vitroceramics

  38. Change in B-O-Al connectivity upon crystallization detected by 11B{27Al} REDOR 20Y2O3 - 20Al2O3 - 60B2O3 g-B2O3 43% of the B(3) units are not linked to aluminum in the vitroceramic

  39. Glass - to - vitroceramic transition for the system 40-y (Al2O3) - y Y2O3 – 60 B2O3 (B2O3)0.6(Al2O3)0.4-y)(Y2O3)y{(0.8/3) - (2y/3)} YAl3(BO3)4 + {(8y/3)-0.8/3} YBO3 + 0.2B2O3

  40. 2nd Approach: NMR Analysis of paramagnetic effects uponthe constituent matrix nuclei: HZ and T1 Rapid electron Zeeman state fluctuations (short T1e): d = dFermi + ddip + ddia (1) dFermi ~ {µB2/kBT}gisoBor ~ cMr (2)ddip ~ {µB2/kBT}r-3{gzz2- ½(gxx2 + gyy2)}(3cos2q-1) • Isotropic shift contribution • Isotropic shift contribution + broadening effects

  41. Al2O3)0.2(Y2O3)0.2(B2O3)0.6 : Nd3+, Er3+,and Yb3+ subst. Yb3+ Nd3+ Er3+ BO3 BO4

  42. Distribution of the RE ions in theceramics: 27Al MAS-NMR results 10Y-30Al-60B 20Y-20Al-60B YAl3(BO3)4 YAl3(BO3)4 in phase mixture Linewidths and areas of new Al site are proportional to Yb/Y ratio H. Deters, A. S. S. De Camargo, C. N. Santos, H. Eckert, J Phys. Chem. C 114,14618 (2010)

  43. Linewidth (11B) Linewidth (27Al) Peak area (27Al) Linewidth (89Y) Apparent Yb/Y ratio in the YAB component of VC-Y20 lower than predicted preferential location of Yb in YBO3 component Preferential location of Nd in YAl3(BO3)4 component

  44. 3. ESEEM - Electron Spin Echo Envelope Modulation typical excitation window • applied at a particular fixed field strength • systematic variation of the pulse spacing (t+Dt) • Modulation effect results from the simultaneous excitation of allowed (Dms=±1, DmI=0) and partially forbidden (Dms=±1, DmI≠0 nuclear spin-flip) EPR transitions. wa = [(wI + A/2)2 + B2/4]1/2 wß = [(wI - A/2)2 + B2/4]1/2

  45. ESEEM Spectra of Yb-doped Glasses in the System xY2O3-(40-x)Al2O3-60B2O3

  46. Summary Solid State NMR as a promising tool in optical glasses • Strategy for structural studies of rare earth ions in optical glasses • Influence of rare earth ions upon the framework structure • First 45Sc and 89Y NMR in glasses • First ESEEM of alumoborate glasses • Study of crystallization mechanism and dopant distributions in Y-alumoborate vitroceramics • Substitution preference for Yb3+ ions

  47. Thank you • Dr. Heinz Deters • Frederik Behrends • Drs. J. F. de Lima, C. J. Magon (IFSC, USP) • Dr. A.S.S. de Camargo (IFSC, USP) • SFB 458 • NRW Graduate School of Chemistry • Fond der Chemischen Industrie

  48. AK Eckert, WWU Münster Prof. H. Eckert Prof. H.J. Deiseroth (University of Siegen) S.T. Kong (University of Siegen) SFB 458 Thanks for your attention!

  49. 31P MAS NMR of Li7PS5-xSexCl PS4 PS2Se2 PSSe3 PSe4 PS3Se Increasing S content Increasing Se content Resolution of first and second coordination sphere P-S bonding favored over P-Se bonding

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