Fabrication and Characterization of Novel Hybrid Nanocomposites with Application in Solar Cells
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Doctor of Philosophy Dissertation Fabrication and Characterization of Novel Hybrid Nanocomposites with Application in Solar Cells Dimitris A. Chalkias Dipl.-Ing Mechanical Engineering & Aeronautics Supervisor: G.C. Papanicolaou Dissertation Submitted to the University of Patras for the Award of the Degree of DOCTOR OF PHILOSOPHY in Mechanical Engineering & Aeronautics Patras, 2019 Πανεπιστήμιο Πατρών, Τμήμα Μηχανολόγων & Αεροναυπηγών Μηχανικών Δημήτριος Α. Χαλκιάς © 2019 – Με την επιφύλαξη παντός δικαιώματος Examination Committee 1. George Papanicolaou (Dissertation Supervisor) Professor Emeritus, Department of Mechanical Engineering & Aeronautics, University of Patras, Greece 2. Vassilis Kostopoulos (Dissertation Advisor) Professor, Department of Mechanical Engineering & Aeronautics, University of Patras, Greece 3. Theodoros Loutas (Dissertation Advisor) Assistant Professor, Department of Mechanical Engineering & Aeronautics, University of Patras, Greece 4. George Psarras Associate Professor, Department of Materials Science, University of Patras, Greece 5. Dimitris Kondarides Professor, Department of Chemical Engineering, University of Patras, Greece 6. Joannis Kallitsis Professor, Department of Chemistry, University of Patras, Greece 7. Thomas Stergiopoulos Assistant Professor, Department of Chemistry, Aristotle University of Thessaloniki, Greece Approval of Ph.D. Dissertation of Mr. Dimitris A. Chalkias Willpower is the key to success. I dedicate this work to my Mother, who always supported me and believed in me. Preface The present Ph.D. dissertation is the outcome of six years of research as a Ph.D. Candidate at the Department of Mechanical Engineering & Aeronautics, University of Patras, Greece, under the supervision of Professor George C. Papanicolaou. Ph.D. Dissertation Outline The present Ph.D. dissertation concerns the application of hybrid nanotechnology in dye-sensitized solar cells (DSSCs), with the main goals of improving their energy conversion efficiency and stability, further reducing their manufacturing cost, and increasing their application range. The dissertation resulted in two published papers in international scientific journals, and seven more already submitted or close to submission. The Ph.D. dissertation is divided into two main sections and consists of six chapters. ➢ Section 1 The first section, which consists of three chapters, describes the current knowledge about the topic of photovoltaics, focusing on DSSCs technology, while the motivation and the research objectives of the Ph.D. dissertation are also presented. In Chapter 1, there is a brief introduction to the recent photovoltaics market trends and solar cell technologies, while the reasons for focusing on DSSCs technology for research, development, and optimization are explained. In Chapter 2, there is an extensive reference to DSSCs technology, presenting a historical background, their design, their operating principle, and their equivalent circuit analysis based on the literature. Chapter 3 provides the state of the art of DSSCs technology, presenting the latest and most important international scientific research efforts to improve the characteristics of DSSCs, from any point of view. In this chapter, the motivation and the research objectives of the Ph.D. dissertation are also presented. ➢ Section 2 The second section of the Ph.D. dissertation, which consists of three chapters, concerns the experimental part. In Chapter 4, the materials, the fabrication and characterization methods, as well as all the experimental setups used in the present research are presented. Chapter 5 concerns the results and discussion part of the dissertation. Chapter 6 lists the most important conclusions and achievements, while future research is also suggested. I Acknowledgements First of all, I would like to express my sincere appreciation for my supervisor, Prof. G.C. Papanicolaou, for giving me the opportunity to pursue my Ph.D. dissertation under his supervision. His guidance always challenged me intellectually and provided the perfect ambience needed to grow as a Ph.D. Candidate, while his constructive criticism and support led me to successfully complete my Ph.D. dissertation. I am also really grateful to him for assigning such an interesting research topic to me, which I would like to follow throughout my next steps of research activity. Additionally, I would like to thank my Ph.D. committee members Prof. V. Kostopoulos, T. Loutas, G.C. Psarras, D.I. Kondarides, J.K. Kallitsis, and T. Stergiopoulos, as well as Prof. E. Stathatos and S. Bebelis. For all the aforementioned Professors, I hold a deep appreciation for their open-handed support all these years. All the aforementioned Professors are very respected by me for their research activity and in many cases are examples to follow. The present Ph.D. dissertation would not have progressed without the help of the laboratory members, Alexis Laios, Dimosthenis Giannopoulos, Dimitris Tasiopoulos, Ioanna Margariti, Dimitris Loizos, and Nektarios Verykokkos, with whom we worked well on the topic of solar cells, serving as co-supervisor of their diploma thesis at the Department of Mechanical Engineering & Aeronautics. Many thanks also to the rest of the lab members for their friendship and support, especially to Lykourgos Kontaxis, with whom we worked side by side all these years of my Ph.D., and Diana Portan for our kind collaboration. I would further like to thank Ms. V. Tsoukala for her assistance in the scanning electron microscopy measurements, Prof. S. Zaoutsos for his assistance in the energy-dispersive X-ray spectroscopy measurements, Ms. P. Lampropoulou for her assistance in the X-ray diffraction measurements, Dr. G. Michanetzis for his assistance in the atomic force microscopy measurements, Prof. P. Koutsoukos for providing technical equipment for the Brunauer–Emmett–Teller analysis measurements, Prof. D.I. Kondarides for providing technical equipment for the ultraviolet-visible spectroscopy measurements, Dr. A. Petala for her assistance in the ultraviolet-visible spectroscopy and diffuse reflectance spectroscopy measurements, Prof. E. Stathatos for providing technical equipment for the photoluminescence spectroscopy measurements, Prof. V. Kostopoulos for providing technical equipment for the differential scanning calorimetry measurements, Ms. E. Kollia for her assistance in the differential scanning calorimetry measurements, Prof. E. Stathatos for providing technical equipment for the Fourier-transform infrared spectroscopy measurements, Dr. A. Soto for her assistance in the Fourier-transform infrared spectroscopy measurements, Prof G.C. Psarras for providing technical equipment for the electrochemical impedance spectroscopy measurements, Prof. J.K. Kallitsis for providing technical equipment for the linear sweep voltammetry measurements, Prof. D.I. Kondarides for providing technical equipment for the cyclic voltammetry measurements, Dr. A. Petala for her assistance in the cyclic voltammetry measurements, Prof. G.C. Psarras for providing technical equipment for the dynamic mechanical analysis measurements, Mr. S. Stavropoulos for his assistance in the dynamic mechanical analysis measurements, and Mr. Dimitris Fakos for providing technical equipment for the solar cells characterization. The difficulties in my Ph.D. dissertation were not exclusively scientific, but often human. After all, the effort was solitary and long-lasting and its side effects in my personal life varied. The value of psychological and moral support in difficult times is not valued and not forgotten. I would not like to offend the people who have shared my worries and my anxiety over these years, mentioning some of them and ignoring others. But at the same time, it is impossible not to mention to my family and special thank them for all their love, continuous support, and encouragement. Without them, executing my Ph.D. dissertation would not be feasible. Additionally, I also feel the need to refer to my girlfriend Theodora and thank her for being next to me, in every sense, in all these years during my Ph.D. II Last but not least, I would like to acknowledge the contribution of all those who, in one way or another, have questioned me and/or my choices. Without their own doubt, my stubbornness may have been premature. I thank them from my heart for bringing out the best in me. Dimitris A. Chalkias Ph.D. Candidate Dept. of Mechanical Engineering & Aeronautics University of Patras February 2019 Ph.D. Candidate Qualifications The overall image of the Ph.D. Candidate is shown below: A) Four publications in international scientific journals. B) Twelve publications in international and national conferences. C) In 2015, he gave an invited talk at the symposium held at the University of Patras, entitled “Green University”. D) He is a reviewer of papers in five international scientific journals, namely Electrochimica Acta (I.F. 5.1), Ionics (I.F. 2.3), Journal of Materials Science: Materials in Electronics (I.F. 2.3), Advances in Materials Science and Engineering (I.F. 1.4), and Heliyon (I.F. 1.2). E) He has provided ancillary work in the framework of teaching exercises and applications in the courses “Special Physics for Engineers” (Department of Mechanical Engineering & Aeronautics, University of Patras), "Physics for Chemists" (Department of Chemistry, University of Patras), "Introduction to Composites" (Department of Mechanical Engineering & Aeronautics, University of Patras). F) He was co-supervisor of six diploma theses carried