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SYNTHESIS of NEW NANOCRYSTAL MATERIALS by Yasser Hassan Abd El-Fattah Hassan a Thesis Submitted in Conformity with the Requireme

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SYNTHESIS of NEW NANOCRYSTAL MATERIALS by Yasser Hassan Abd El-Fattah Hassan a Thesis Submitted in Conformity with the Requireme SYNTHESIS OF NEW NANOCRYSTAL MATERIALS by Yasser Hassan Abd El-Fattah Hassan A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Department of Chemical Engineering and Applied Chemistry University of Toronto © Copyright by Yasser Hassan 2016 Synthesis of New Nanocrystal Materials Yasser Hassan Doctor of Philosophy Department of Chemical Engineering and Applied Chemistry University of Toronto 2016 Abstract Colloidal semiconductor nanocrystals (NCs) have sparked great excitement in the scientific community in last two decades. NCs are useful for both fundamental research and technical applications in various fields owing to their size and shape-dependent properties and their potentially inexpensive and excellent chemical processability. These NCs are versatile fluorescence probes with unique optical properties, including tunable luminescence, high extinction coefficient, broad absorption with narrow photoluminescence, and photobleaching resistance. In the past few years, a lot of attention has been given to nanotechnology based on using these materials as building blocks to design light harvesting assemblies. For instant, the pioneering applications of NCs are light-emitting diodes, lasers, and photovoltaic devices. ii Synthesis of the colloidal stable semiconductor NCs using the wet method of the pyrolysis of organometallic and chalcogenide precursors, known as hot-injection approach, is the chart-topping preparation method in term of high quality and monodisperse sized NCs. The advancement in the synthesis of these artificial materials is the core step toward their applications in a broad range of technologies. This dissertation focuses on exploring various innovative and novel synthetic methods of different types of colloidal nanocrystals, both inorganic semiconductors NCs, also known as quantum dots (QDs), and organic-inorganic metal halide-perovskite materials, known as perovskites. The work presented in this thesis focuses on pursuing fundamental understanding of the synthesis, material properties, photophysics, and spectroscopy of these nanostructured semiconductor materials. This thesis contains 6 chapters and conclusions. Chapters 13 focus on introducing theories and background of the materials being synthesized in the thesis. Chapter 4 demonstrates our synthesis of colloidal linker–free TiO2/CdSe NRs heterostructures with CdSe QDs grown in the presence of TiO2 NRs using seeded–growth type colloidal injection approach. Chapter 5 explores a novel approach of directly synthesized CdSe NCs with electroactive ligands. The last Chapter focuses on a new class of perovskites. I describe my discovery of a (bottom-up) simple method to synthesize colloidally stable methyl ammonium lead halide perovskite nanocrystals seeded from high quality PbX2 NCs with a pre-targeted size. This chapter reports advances in preparation of both these materials (PbX2, and lead halide perovskite NCs). iii Dedication To My Parents and My Stepmother To My Wife Marwa H. Ibrahim To My Brothers and Sisters To My Beautiful Kids To My Teachers To My Family iv To Every knowledge seeker: Al-Khatib al-Baghdadi stated in his book “The History of the City of Peace: The History of Baghdad” that: Imam Al-Juwayni (died 1085) wrote to one of his students said Imam Al-Shafi‘i wrote a rhyme of poetry: أخي لن تنال العلم إﻻ بستة سأنبئك عن تفصيلها ببيان ذكاء وحرص وافتقار وغربة وتلقين أستاذ وطول زمان “Oh my brother you will never become a scholar until you complete the six pillars of THE REQUISITES OF KNOWLEDGE: A QUICK MIND, ZEAL FOR LEARNING, POVERTY, FOREIGN LAND, A PROFESSOR'S INSPIRATION, AND OF LIFE A LONG SPAN.” End of Quote! v Acknowledgments I would like to thank a number of individuals, without their unique insights and wisdom, I would have struggled to find the motivation, enthusiasm, inspiration, support, and guidance to complete this work. First of all, I wish to express my deepest gratitude to my advisors, Professor Gregory D. Scholes and Professor Mitch Winnik for their inspiration, continued encouragement, priceless suggestions, and support while working in Toronto. Their mentorship has helped me become a better scientific writer, strategic planner and critical thinker about science. I would like to express my profound appreciation to my advisor Professor Scholes who graciously welcomed my visit to his lab 20092010 and then provided me with the incredible opportunity to complete my Ph.D. at the University of Toronto. There is no doubt without his continued encouragement, invaluable suggestions, invaluable mentorship, exceptional support and keen insights, patient guidance, I would not have made it to this stage of success. Greg became more of a mentor and friend than a professor. Moreover, the work environment in Professor Scholes’ lab was a fantastic experience. Additionally, I would like to thank Professor Tim Bender and Professor Dwight Seferos for being members in my committee and for all of their help and kind suggestions related to my research. I am indebted to Professor Bender to be a friend and mentor. Thanks Tim! This is highly appreciated. I would like to thank Professor Zheng-Hong Lu and Professor Peng Zhang for their willingness to spend time reading this thesis and be part of my departmental examination. I would also like to thank and to express deep appreciation to my coworkers who assisted me on these research projects. I am so thankful to my colleagues and friends at the university, especially the ones in the Scholes and Winnik groups. They were all exceptional people. All of their support vi and encouragements helped me significantly toward the completion of my studies at the University of Toronto. The following is a list of all my former and current coworkers and colleagues who helped me carry out the different research projects at the University of Toronto. I was fortunate to work within this environment. In particular I would like to thank my friend and colleague Ahmed Abdelrahman for working on the documents, renting an apartment, and his countless support during my the past seven years. Thanks Ahmed. I feel you are one part of the family. I would to thank Dr. Anna Lee and Dr. Gerald Guerin for their advice and support. I thank my current and former fellow labmates from Scholes group. I would like to thank Dr. Haizheng Zhong and Yaser Khan for all their insightful comments and help provided in the beginning of my work in Scholes’ lab. I would like to thank my friend Dr. Mahmoud Dawood (University of Zagazig) for helping in reproducing Figures 2.12, 3.1 and 3.2. An acknowledgement with a very special thanks goes out and deeply appreciation to Dr. Ryan Pensack, Dr. Yoichi Kobayashi, Dr. Yin Song, and Dr. Elsa Cassette. Without whose encouragement and technical support, I would not have finished up my Chapters 5 and 6 of this thesis. Special thanks for Dr. Ryan Pensack (the Boss) for being a fantastic mentor, always helping and being the greatest friend. Boss, I am so indebted for having you during my PhD!! I must also acknowledge my collaborators: (a) Professor Clemens Burda and his student Chi-Hung Chuang for their insightful comments and help provided for transient absorption measurements done for the colloid linker-free TiO2/CdSe Nanorods synthesis project which presented in Chapter 4. (b) Professor Datong Song and his student Trevor Janes for their insightful comments and involvement in the “Direct Synthesis of CdSe Nanocrystals with Electro-active Ligands” project vii found in Chapter 5 of this thesis. (c) Professor Axel Guenther and his students Milad Abolhasani, Parnian Saberi for their collaborations. I gratefully acknowledge the funding sources that funded my Ph.D. work. First I thank the Egyptian Ministry of Higher Education for funding my visit to U of T in 20092010 and the Natural Sciences and Engineering Research Council of Canada (NSERC) for funding my PhD work. This financial support has enabled me to focus on my professional and scientific development. It is my hope that our efforts in this thesis can add to a better quality of life throughout the world. I would like to thank my entire family and long-time friends for their love, support and encouragement. I would like to express profound gratitude and deeply appreciation to my parents and all siblings from whom I got unconditional love and inspiration that shaped my actions and morals. Last and not least, I am greatly indebted to of my beautiful wife, Marwa Hamza Ibrahim. None of this could have happened without her patience and sacrifices. I am thankful for her endless love and encouragement. Marwa, you are always there cheering me up, supporting me spiritually throughout my good times and bad times of our life. I thank my lovely kids. You are a blessing in my life. Thanks God!! To you all, without you this thesis would not have been possible. I thank you. viii Table of Contents Abstract…………………………………………………………………………………………..ii Acknowledgments ........................................................................................................................ vi Table of Contents ......................................................................................................................... ix List of Tables .............................................................................................................................. xiv List of Figures .............................................................................................................................. xv List of Abbreviations ..............................................................................................................
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