Synthesis and Application of Functional π-materials based on Quinoxaline for DSSCs

Abstract

With the increase of interest in alternative energy owing to the depletion of fossil fuels and environmental problems, solar energy is attracting attention as a one of the future energy resource due to its abundance, non-pollution, sustainability, and ease of access. Of the various solar cells developed so far, dye-sensitized solar cells (DSSCs), which cost is about 30% compared to that of the conventional silicon-based solar cells, have been researched because of not only low cost but also easy manufacturing process, less environmental issues, and high power conversion efficiency under indoor light. To develop efficient and cheap sensitizer, which is one of components for DSSCs and plays a tremendous role, many researchers have developed new metal organic sensitizers. During my doctoral course, the study was conducted to optimize the molecular structure of the novel quinoxaline-based metal-free organic sensitizer and investigate the structure-property relationship of the sensitizers to lead controlling factors for improving cell performance. To achieve above purpose, the researches containing various subject were conducted as follows: the effect of different electron donating group, the influence of di-anchoring group and the substitution patterns, the impact of π-conjugation length and the insertion of a thiophene unit as π-spacer on the performance of solar cell. In this thesis, overall synthetic methods containing useful organic chemical reactions and the manner for the preparation and evaluation of dye-sensitized solar cell were included. The results and discussions provide the insight about the structure-property relationships of quinoxaline-based sensitizers and the considerations for design of the improved organic molecules for DSSCs.