Design, Synthesis and Modelling of Conjugated Polymers for Organic Photovoltaics

Abstract: Secure, clean and renewable energy sources are believed to be the eventual solution for sustainable energy, especially by the direct utilization of solar energy. Organic photovoltaics offer such an option to convert solar energy into electricity based on solution-processed, lightweight, large-area, and potentially flexible devices. The current challenges for organic photovoltaics remain to further improve efficiency as well as durability and cost-effectiveness, to compete with traditional silicon-based solar cells. Material design through band gap and energy level tuning has been playing a key role in developing new donor materials for efficient polymer solar cells. Computationally driven material design can accelerate the search for optimal conjugated polymers, and the exploration of chemical methodologies is highly desirable in pushing the efficiency further toward the theoretical limit. This thesis deals with the design, synthesis, characterization, and computational modelling of π-conjugated polymers for bulk heterojunction organic solar cells. It focuses on material design of conjugated donor polymers through band gap and energy level engineering via structural modifications such as backbone manipulations, side-chain engineering, as well as incorporation of newly developed building blocks. This also establishes structure–property relationships of the polymer systems here studied, and explores potential chemical methodologies for future judicious material design.