SusChEM: Interfacial Interactions and Electron Transfer in Dye-Sensitized Systems for Photovoltaics and Photocatalysis

College Of William And Mary, Williamsburg VA

Investigators

Abstract

With this award, the Chemical Structure, Dynamics, and Mechanism B Program (CSDMB) of the Chemistry Division is supporting the research of Professor Kristin Wustholz of the Department of Chemistry at the College of William and Mary to study organic dye-sensitized systems for use in next-generation solar energy conversion materials and devices. Organic dye sensitizers are molecules that can be used to harvest sunlight for energy related applications. They work by absorbing the light needed to excite an electron in the dye to a higher energy level. This high energy electron is then transferred to a semiconducting material. The use of an organic dye sensitizer for this effort is particularly attractive because they are made of earth-abundant, inexpensive materials. However, their use also comes with a cost in that their use is frequently complicated by the low efficiency of electron-transfer between the dye and the semiconductor and the poor long-term stability of the dye-semiconductor complex. The goal of this project is to solve these problems by learning how to optimize the light-harvesting ability of organic dye sensitizers while maintaining both the electron-transfer efficiency and stability of the dye-semiconductor complexes. By addressing these problems, the Wustholz group is contributing to efforts to address current issues related to the growing demand for renewable energy. At the same time, the research is providing meaningful research and developmental experiences for undergraduate and master's degree students who are being trained in physical, analytical, and materials chemistry. During the budget period, the Wustholz group is continuing its efforts to develop the research and communication skills of underrepresented students through long-term, mentored research experiences, as well as outreach activities that are aimed at increasing the number of such students that are exposed to meaningful scientific experiences. The central goal of this project is to understand the interfacial interactions and electron-transfer processes occurring in organic-dye-based systems for dye-sensitized solar cells and photocatalysis. Organic dye sensitizers consist of earth-abundant elements, possess high absorption coefficients, and have the potential for enhanced light harvesting through controlled surface aggregation. In this work, the Wustholz group will pursue three main strategies to understand and optimize the optical and electronic properties of organic-dye-based systems for solar-to-electrical and solar-to-fuel conversion: 1) determine the structure-activity relationships of surface-aggregated organic dyes, 2) elucidate the interfacial electron-transfer processes and kinetic dispersion at the molecular level, and 3) probe the impact of operational variables on molecular aggregation and interfacial kinetics for surface-anchored organic dyes. This project contributes to our fundamental understanding of solar energy conversion and to the development of new approaches to efficiently convert solar photons into chemical energy.