[Please contact me (maxthebuilder @ gmail.com) if you are interested in reading the whole thing. Below follows the table of contents.]

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

1. INTRODUCTION

1.1 INTERCALATION IN LAYERED MATERIALS

  • Background
  • Reaction Chemistry
  • Structural Aspects
  • Host Structure
  • Staging and Related Phenomena
  • In-plane Structure
  • Structural Characterization

1.2 THIS WORK

  • Motivation
  • HgxTiS2 (0.00< x<1.24): a Model Weak Charge Transfer Intercalation System
  • Objective
  • Organization

 

2. EXPERIMENTAL

2.1 MATERIALS PREPARATION

  • Host Material
  • Intercalate

2.2 TEM SAMPLE PREPARATION AND HANDLING

2.3 IMAGE PROCESSING AND SIMULATION

  • Image Processing
  • HRTEM Image Simulation

 

3. DHRTEM OF MERCURY-INTERCALATED TiS2

3.1 INTRODUCTION

3.2 EXPERIMENTAL

3.3 GENERAL OBSERVATIONS

3.4 ONSET OF DEINTERCALATION

  • External-Layer Onset
  • Internal-Layer Onset

3.5 PROGRESSION OF DEINTERCALATION

  • After External-Layer Onset
  • After Internal-Layer Onset
  • General Progression and Staging

3.6 GUEST AND HOST-LAYER BEHAVIOR DURING DEINTERCALATION

  • Guest-Layer Separation and Island Formation
  • GED Deintercalation and Island Formation
  • GEDs: Formation of Stable Staggered Domain Walls
  • Symmetric and Asymmetric GED Terminations

3.7 CONCLUSIONS

 

4. STRUCTURE OF MERCURY-INTERCALATED TiS2

4.1 INTRODUCTION

4.2 EXPERIMENTAL

4.3 TEM INVESTIGATIONS OF HgXTiS2

  • General Observations
  • In-plane Structure
  • Crystal Structure

4.4 XPD INVESTIGATIONS of Hg1.24TiS2

4.5 DISCUSSION

  • Intriguing Structural Transition Induced by Deintercalation
  • Structure of the Equilibrium Compound
  • Guest-Host Electronic Interactions

 

5. CONCLUSIONS

5.1 SUMMARY

  • Deintercalation Processes in Hg1.24TiS2
  • Structures of HgxTiS2

5.2 FUTURE RESEARCH

 

LIST OF TABLES

  1. Internal-Layer Deintercalation Onset Associated with Surface and Internal Defects
  2. Parameters of the 96 HgxTiS2 Structure
  3. Parameters of the 102 HgxTiS2 Structure
  4. X-ray Powder Diffraction Data for Hg1.24TiS2
  5. Crystallographic Data for Hg1.24TiS2
  6. Atomic Coordinates and Thermal Parameters for Hg1.24TiS2
  7. Atomic Distances and Angles for Hg1.24TiS2
  8. Main Features of the HgxTiS2 Deintercalation Process
  9. Structural Properties of HgxTiS2

LIST OF FIGURES

  1. Intercalation systems as hybrids between solid and fluid phases
  2. Host lattices with different structural dimensionality
  3. Schematic diagram of the intercalation process in which guest species penetrate between host layers
  4. Main factors determining the structure of an intercalation compound
  5. Basic structural features of lamellar dichalcagenides TX2
  6. Classical model of staging
  7. Daumas-Hrold guest-island model of staging
  8. Perspective view of a block of 2x2x2 pseudo-monoclinic unit cells of TiS2
  9. Thermogravimetric analysis of stage-1 Hg1.24TiS2.
  10. Liquid-nitrogen grinder
  11. Main steps of Fourier image processing
  12. Deintercalation onset in HgxTiS2
  13. Internal-layer deintercalation onset associated with irregular host-layer termination at the crystal edge
  14. Internal-layer deintercalation onset associated with a host-edge dislocation
  15. Internal-layer deintercalation onset associated with an interlayer defect
  16. Typical Hg1.24TiS2 deintercalation progression after external onset
  17. Typical Hg1.24TiS2 deintercalation progression after internal onset
  18. Guest-layer separation and deintercalation
  19. Guest-island separation from a deintercalating GED and their subsequent deintercalation
  20. Daumas-Hrold domain walls
  21. An extensive staggered domain-wall boundary
  22. Transition from a symmetric to an asymmetric GED termination during guest-layer deintercalation
  23. A sequence of high resolution images showing the process of formation of an asymmetrical GED
  24. High resolution images of partially deintercalated Hg1.24TiS2 microcrystals containing GEDs
  25. Bright field TEM images of HgxTiS2 microcrystals
  26. Typical SAD patterns of HgxTiS2 obtained with the electron beam nearly perpendicular to the layers
  27. Schematic depiction of the SAD pattern shown in 26d and the two possible interpretations of this pattern
  28. The most typical SAD pattern obtained along c
  29. A model of the in-plane structure of HgxTiS2 viewed perpendicular to layers showing the formation of partially commensurate Hg guest layers
  30. Three crystallographically equivalent orientational variants of the mercury layers
  31. HRTEM image of HgxTiS2 along the c-axis of a thin area
  32. Separation of the host and Hg sublattice by Fourier image processing
  33. Separation of the host and Hg sublattices by Fourier image processing
  34. Comparison of an SAD pattern obtained from a thin area of HgxTiS2 and a FFT of the corresponding HRTEM image
  35. HRTEM image of a very thin region of HgxTiS2 taken along Hg chains (b axis) representing the only commensurate plane of the structure
  36. The four possible unit cells of HgxTiS2 obtained by expanding of the TiS2 lattice and then by rigid gliding of the host layers along a by discrete distances in 1/6a increments
  37. Schematic illustration of the two alternative structures of HgxTiS2
  38. Defocus/thickness maps (computer simulations)
  39. A HRTEM image along b showing the commensurate a-c plane of HgxTiS2
  40. A HRTEM image along c showing a partially commensurate a-b plane
  41. Hg occupancy vs. defocus map of calculated images for the 96 structure
  42. Observed and calculated X-ray powder diffraction patterns for Hg1.24TiS2 at ambient temperature
  43. An x cross section through the c 2 surface of the Rietveld refinement showing the similar fit for 0.23<x<0.27 in the three-phase refinement suggesting the x coordinate of the Hg chains is not well defined
  44. A highly magnified HRTEM image of HgxTiS2 along c
  45. A schematic depiction of the coexistence of the b=102 and b=96.5 HgxTiS2 structures with coherent (1/2)b host layer shifts between the structures
  46. A HRTEM image of HgxTiS2 along a showing substantial disorder in partially commensurate b-c plane resulting from the incommensurate nature and the disorder of the Hg chains along b
  47. A Fourier-processed HRTEM image along c taken from a region close to the edge of a HgxTiS2 crystal
  48. Nearest-neighbor Hg-S distances are indicated by the dark line as a function of the y coordinate of the Hg position, yHg, within the TiS2 sublattice unit cell
  49. A comparison of intrachain Hgn+-Hgn+ bond distances as a function of n for compounds containing linear Hg chains
 
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