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Hydrothermal Crystal Growth of Metal Borates for Optical Applications Carla Heyward Clemson University, [email protected]

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Hydrothermal Crystal Growth of Metal Borates for Optical Applications Carla Heyward Clemson University, Carlacheyward@Gmail.Com Clemson University TigerPrints All Dissertations Dissertations 8-2013 Hydrothermal Crystal Growth of Metal Borates for Optical Applications Carla Heyward Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Part of the Chemistry Commons Recommended Citation Heyward, Carla, "Hydrothermal Crystal Growth of Metal Borates for Optical Applications" (2013). All Dissertations. 1164. https://tigerprints.clemson.edu/all_dissertations/1164 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. HYDROTHERMAL CRYSTAL GROWTH OF METAL BORATES FOR OPTICAL APPLICATIONS A Dissertation Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Chemistry by Carla Charisse Heyward August 2013 Accepted by: Dr. Joseph Kolis, Committee Chair Dr. Shiou-Jyh Hwu Dr. Andrew Tennyson Dr. Gautam Bhattacharyya ABSTRACT Crystals are the heart of the development of advance technology. Their existence is the essential foundation in the electronic field and without it there would be little to no progress in a variety of industries including the military, medical, and technology fields. The discovery of a variety of new materials with unique properties has contributed significantly to the rapidly advancing solid state laser field. Progress in the crystal growth methods has allowed the growth of crystals once plagued by difficulties as well as the growth of materials that generate coherent light in spectral regions where efficient laser sources are unavailable. The collaborative progress warrants the growth of new materials for new applications in the deep UV region. This work involves the use of hydrothermal crystal growth for exploring the descriptive chemistry of various metal borate systems in which several new structures were isolated. Conventional melt-based crystal growth methods can be problematic in synthesizing metal borates due to incongruent melting as well as the typical viscous nature of the borate flux melts. This can lead to glassy products making it difficult to grow optical quality metal borate single crystals. Due to these difficulties, other synthetic methods such as hydrothermal crystal growth for these types of materials are explored. The motivation for the exploratory research of this system derives from the commercially important β-BaB2O4 and LiB3O5. Both materials have excellent properties however; generation of coherent light below 225 nm is inefficient due to low transmittance in the deep UV region. Similarly, several other known metal borates have good optical properties but they all have limitations. For example, beryllium containing borate ii KBe2BO3F2 (KBBF) have been of interest in the recent years because it generates coherent light in the deep UV region; however, a problem exists with the layered structure preventing high quality crystals from forming. Hydrothermal technique has proven to be an attractive alternative crystal growth method, especially with the growth of good quality KBBF crystals. This dissertation explores the descriptive crystal chemistry of hydrated alkali and alkaline earth borate systems in an attempt to grow β−BaB2O4 or similar analogs. In an effort to improve the thermal properties of hydrated borates, this work was also extended to systematically introduce more stable anions and oxyanions into the borate lattice. Furthermore, preliminary photoluminescence of europium doped borate and borosilicate structures give information about their optical properties and potential applications. The work with europium led to a new rich class of europium silicates and borosilicates in which several new structures were uncovered. The formation of these new materials demonstrates the versatility of the crystal chemistry of metal borates under hydrothermal conditions. iii DEDICATION I dedicate this work to my parents Robert and Ellen Heyward, who taught me the value of hard work and the importance of having a relationship with God. “If you have faith as small as a mustard seed, you can say to this mountain, „Move from here to there‟ and it will move. Nothing will be impossible for you.” Matthew 17:20 iv ACKNOWLEDGMENTS I would like to extend my deepest gratitude to my advisor, Dr. Joe Kolis for his guidance; I have truly grown immensely as a scientist. I would also like to thank Dr. Hwu, Dr. Tennyson and Dr. Bhattacharyya for serving as members of my committee. I am very grateful to Dr. Colin McMillen for his insightful discussions about hydrothermal crystal growth and X-ray crystallography. I cannot thank Dr. Frankie Felder and the Southern Regional Education Board (SREB) staff enough for everything they have done to help my journey through this last year of graduate school easier professionally and financially. I have had the pleasure of working with some fantastic people in the Kolis group over the years. I would like to thank all of the past and present members which include Dr. Colin McMillen, Dr. Matthew Mann, Evy Colon-Garcia, Sara Comer, Cheryl Moore, Dr. Martin Kimani, Chris Underwood, Kyle Fulle, and Rylan Terry. Their support and eagerness to assist me with anything and everything has been greatly appreciated. To Will Wannamaker, I thank you for always being a friend to listen and distract me from the craziness of grad school. Last but certainly not least, I would like to thank my family and friends for their love and support through this academic journey. I am particularly grateful to my parents for their unselfish sacrifices in giving me the independence to explore different activities growing up and allowing me to follow the path that I have chosen. To my older siblings, Tora, Roberta and Robert Jr., I thank you for the friendship, love and financial support which gave me strength to strive for excellence. v TABLE OF CONTENTS Page TITLE PAGE .................................................................................................................... i ABSTRACT ..................................................................................................................... ii DEDICATION ................................................................................................................ iv ACKNOWLEDGMENTS ............................................................................................... v LIST OF TABLES ........................................................................................................... x LIST OF FIGURES ...................................................................................................... xiv CHAPTER I. INTRODUCTION ......................................................................................... 1 Historical Review of Crystals .................................................................. 1 Traditional Crystal Growth Methods ....................................................... 2 Development of Hydrothermal Crystal Growth Techniques ................... 5 Overview of Research in Metal Borates and Their Industrial Importance ............................................................. 10 Research Motivations............................................................................. 14 References .............................................................................................. 16 II. EXPERIMENTAL METHODS................................................................... 19 Synthetic Methods ................................................................................. 19 Solid State Reactions ....................................................................... 19 Hydrothermal Crystal Growth ......................................................... 20 Characterization Techniques .................................................................. 25 Powder X−ray Diffraction ............................................................... 25 Single Crystal X−ray Diffraction ..................................................... 25 Infrared Spectroscopy ...................................................................... 26 Thermal Analysis ............................................................................. 27 UV−vis Diffuse Reflectance ............................................................ 28 Electron Microscopy (EDX) ............................................................ 28 Photoluminescence Spectroscopy .................................................... 29 References .............................................................................................. 30 vi Table of Contents (Continued) Page III. SYNTHESIS AND CHARACTERIZATION OF HYDRATED METAL BORATES........................................................ 31 Introduction ............................................................................................ 31 Hydrothermal Synthesis of Hydrated Borates and Fluoroborates ................................................................................... 37 The Crystal Structure of Polymorph α−Ba2B7O12(OH) ......................... 56 The Crystal Structure of Sr3B6O11(OH)2................................................ 68 The Crystal Structure of Li2Sr8B22O41(OH)2 ......................................... 83 The Crystal Structure of Sr3B5O9(OH)2F ............................................... 91 The Crystal
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