염료감응형 태양전지를 위한 Polypyridyl Ruthenium (II) 감광제합성 및 특성평가

Abstract

Synthesis and Characterization of Ruthenium (II) Polypyridyl Sensitizers for Dye-Sensitized Solar Cells

Ph.D. thesis submitted by Hong-Minh Nguyen Supervisor: Prof. Nakjoong Kim Department of Chemistry Hanyang University

In order to address the need for CO2-free energy, recent trends in global CO2 emissions and energy production are analyzed, and the photoelectrochemical properties of metal-oxide-based solar cells are presented. The sensitizers play a crucial role in the development of dye-sensitized solar cells (DSSCs). The investigation of new structures of dyes is an effective strategy for improvement of power conversion efficiency of DSSCs as well as device stability. In this thesis, different structure of polypyridyl ruthenium (II) sensitizers based on conjugated ligands are designed and synthesized. Dye-sensitized solar cells using these dyes and nanostructured zinc oxide (ZnO) electrodes were fabricated and characterized. Chapter 1 and 2 provide extensive literature overview into the field of dye-sensitized solar cells. The role and intrinsic properties of dyes and mesoporous metal oxide are addressed and basic concepts of photovoltaic effect are described. The main part discusses molecular engineering of various structures of ruthenium dyes and their performances, briefly summarizing the present state of the art and providing the aim of the research. Chapter 3 and 4 describe the synthesi of conjugated ligands and their physico-chemical properties. As described in chapter 5, we prepared ruthenium dyes employing the above ancillary ligands and their structures and properties analysis by UV-Vis, NMR, CV, MS spectroscopy, respectively. In chapter 6 we attempted to use these dyes in dye-sensitized solar cells. The ZnO was employed as electrode materials. The electrochemical method for preparation of nanostructured ZnO film is also described. The devices were fabricated and characterized by J-V characteristic, IPCE, EIS, and SEM. Chapter 8 describes in detail all experimental part and procedures presented in this work. The result described in this thesis shows that among the various ruthenium dyes designed in this research, the best performance was obtained with DSSC based on Dye-10. This cell shows the efficiency of 4.8% at AM 1.5G solar irradiation. This result is comparable to that of the best ZnO dye-sensitized solar cells reported so far.