The central theme of the proposed research is to explore conjugated diblock copolymers for solar energy harvesting and to gain a fundamental understanding of the correlation between molecular/material structures and photovoltaic (PV) functions. New modular approaches are proposed to the syntheses of three representative new diblock copolymer systems, rod-rod, rodsemi-rod and rod-coil diblock copolymers. Plans are outlined to elucidate and control the self assembly and phase behaviors of the resulting materials. The dynamics of charge separation and charge transport will be investigated to gain insight into the electronic processes in these materials. Rational approach to modify the ITO surface is proposed in order to direct the interfacial assembly of these materials and optimize the charge injection. The resulting materials will be used to prepare prototype solar cells in a well defined cell platform for detailed characterization. The feedback from these studies will reveal the limiting factors in photovoltaic materials and guide the development of new materials. These fundamental studies will eventually lead to breakthrough in developing novel and cost-effective OPV materials enabling high solar energy conversion efficiency as well as future commercial vitality.
The intellectual merit of the proposed activity: This proposed research in syntheses and characterization of novel functional diblock copolymers will have a fundamental impact on our understanding in charge separation and transport in organic materials. The relationship between molecular structure and solid assembly, further between solid structure/physical properties is fundamentally important to polymer science and material science. A well-defined molecular system will lead to the formation of defined solid structures, which is invaluable to the studies in organic light harvesting materials. The proposed work is an important example of new functions that are introduced into diblock copolymer architectures. The modular synthetic approaches proposed here will add new knowledge to the synthetic arsenal. The broader impacts of the proposed activity: Our nation is currently facing an urgent need for renewable energy source. Solar energy is the largest renewable energy source. Plastic solar cells offer potentially low costs in materials and processing, the possibility for large area and flexible structures, and the ease of the structural modification for the fine-tuning of band gaps. The proposed research is highly beneficial towards our economy and society. The proposed efforts will inherently provide ample opportunities for the interdisciplinary training of graduate and undergraduate students at the frontiers of organic/polymer/material chemistry. We plan to integrate the proposed research activities with a broad-ranging educational program aimed at college undergraduate and graduate students. The importance of early involvement of undergraduate students in research activities is widely acknowledged. In this program, we will put a great effort in recruiting more undergraduate students. This project is ideal for training graduate students and enables them to perform original and independent research. From these highly intellectual processes, they will develop creative thinking and skills and become mature scientists.
