Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2018 Exploring the chemical reactivity of group 14 and group 15 molecular precursors Himashi Purnima Andaraarachchi Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Chemistry Commons Recommended Citation Andaraarachchi, Himashi Purnima, "Exploring the chemical reactivity of group 14 and group 15 molecular precursors" (2018). Graduate Theses and Dissertations. 17139. https://lib.dr.iastate.edu/etd/17139 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Exploring the chemical reactivity of group 14 and group 15 molecular precursors by Himashi P. Andaraarachchi A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Chemistry Program of Study Committee: Javier Vela, Major Professor Wenyu Huang Gordie Miller Emily Smith Keith Woo The student author, whose presentation of the scholarship herein was approved by the program of study committee, is solely responsible for the content of this dissertation. The Graduate College will ensure this dissertation is globally accessible and will not permit alterations after a degree is conferred. Iowa State University Ames, Iowa 2018 Copyright © Himashi P. Andaraarachchi, 2018. All rights reserved. ii DEDICATION To Amma and Thaththa iii TABLE OF CONTENTS Page NOMENCLATURE ........................................................................................................ v ACKNOWLEDGMENTS .............................................................................................. vi ABSTRACT .................................................................................................................viii CHAPTER 1. INTRODUCTION .................................................................................... 1 Colloidal nanocrystals and their applications .............................................................. 1 Controlling nanocrystalline phase, composition, and morphology............................... 3 Molecular programming at nanoscale ......................................................................... 4 Thesis organization .................................................................................................... 7 References.................................................................................................................. 8 CHAPTER 2. PHASE-PROGRAMMED NANOFABRICATION: EFFECT OF ORGANOPHOSPHITE PRECURSOR REACTIVITY ON THE EVOLUTION OF NICKEL AND NICKEL PHOSPHIDE NANOCRYSTALS ........................................ 12 Abstract .................................................................................................................... 12 Introduction .............................................................................................................. 13 Experimental section ................................................................................................ 15 Results and discussion .............................................................................................. 18 Conclusions .............................................................................................................. 30 Acknowledgements .................................................................................................. 33 References................................................................................................................ 34 Appendix of supporting information ......................................................................... 43 CHAPTER 3. EVOLUTION OF NICKEL PHOSPHIDE NANOCATALYSTS DURING PHENYLACETYLENE HYDROGENATION ............................................. 55 Abstract .................................................................................................................... 55 Introduction .............................................................................................................. 56 Experimental section ................................................................................................ 57 Results and discussion .............................................................................................. 59 Conclusions .............................................................................................................. 69 Acknowledgements .................................................................................................. 70 References................................................................................................................ 71 Appendix of supporting information ......................................................................... 74 iv CHAPTER 4. GESN HETEROSTRUCTURES: FROM THEORY TO EXPERIMENT ............................................................................................................ 79 Abstract .................................................................................................................... 80 Introduction .............................................................................................................. 80 Experimental section ................................................................................................ 82 Results and discussion .............................................................................................. 85 Conclusions .............................................................................................................. 94 Acknowledgements .................................................................................................. 95 References................................................................................................................ 95 Appendix of supporting information ....................................................................... 101 CHAPTER 5. CONCLUSIONS AND OUTLOOK ..................................................... 104 v NOMENCLATURE TEM Transmission Electron Microscopy PXRD Powder X-Ray Diffraction EDX Energy Dispersive X-Ray Spectroscopy XPS X-Ray Photoelectron Spectroscopy vi ACKNOWLEDGMENTS I am very thankful for having a great mentor and friends who were always willing to share their knowledge and advice with me throughout my five years of graduate school at Iowa State University. I would like to thank my advisor, Javier Vela for his guidance, encouragement, patience, and support during the past four years. He has been a great mentor and taught me a lot about science and research. Thank you for showing me how to be a good researcher, how to improve critical thinking and soft skills, and giving me an opportunity to present my research at national conferences. Next, I would like to thank my committee members, Professors Wenyu Huang, Gordie Miller, Emily Smith, and Keith Woo for their input and guidance throughout this journey. I would like to thank Prof. Smith and Prof. Stanley for giving me the opportunity to collaborate with them. I enjoyed working with their group members and learnt a lot from them. Last five years have been wonderful, thanks to my great colleagues in Vela group. I owe a big thank to Long Men for being the greatest lab partner any one could have asked for. A special thanks to Yijun Guo and Elham Tavasoli for showing me ropes in doing experiments, Michelle Thompson for her kindness, encouraging words, and English lessons, Sam Alvarado, Chia-Cheng Lin, Malinda Reichert, and Feng Zhu for all the great advice. Many thanks to Josie Del Pilar for the guidance in writing prelim proposal, Bryan Rosales and Arthur White for very insightful discussions, Carena Daniels, Alan Gonzales and Lin Wei for being great lab mates. In addition, I would like to thank Supipi akki and Rajeeva ayya for being a family away from home, Sagarika akki and Gayan ayya for their support, Uma akki, Chamari akii, vii and Roshan ayya for their support and valuable input to the research, and Kasuni and Dilini for being greatest friends to share many important moments of graduate life together. Many thanks to my grandparents, immediate family, my cousins, and in-laws for their support and encouragement. More importantly, I want to thank my parents and my sister for their love, support, endless enthusiasm and encouragement throughout all these years. Finally, I want to thank my husband Ravindu for being my side at every step of this journey and for all the love, encouragement, patience and unselfish support. I truly couldn’t have done this without them. viii ABSTRACT Colloidal nanocrystals with their fascinating properties have found many opportunities in a diverse range of applications including optoelectronic and electronic devices, catalysis, and biomedical applications. Performance of nanomaterials in these applications are directly related to the well-defined properties, phase, composition, size, and morphology, of the nanocrystals. Strategies exist to synthesize colloidal nanocrystals with well-defined properties tailored to desired applications by optimization of several parameters such as concentration and nature of precursors and surfactants, temperature, additives, and multi-step procedures, which can be time