International Collaboration in Chemistry: Molecules at Nanostructured Surfaces for Solar Cell Applications

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

This award is made by the Macromolecular, Supramolecular and Nanochemistry program of the Chemistry Division within the International Collaboration in Chemistry between US investigators and their counterparts in Spain and is co-funded by the Office of International Science and Engineering. The recipient is Professor Franz Himpsel of the University of Wisconsin-Madison. This project aims at systematically improving the efficiency of low-cost, dye-sensitized solar cells using a feedback loop between the synthesis of tailored molecules (dyes, donors, acceptors), the spectroscopy of their energy levels, and the theoretical explanation of the spectra, which will be used to identify new molecular structures to be synthesized. Organic molecules excel not only by their low cost, but they also are extremely versatile and allow a wide variety of chemical modifications. The feedback loop has five stages: 1) obtain a library of energy levels in molecules relevant to solar cells, 2) perform excited state calculations and analyze the spectroscopic data from NEXAFS and photoemission, 3) synthesize tailored molecules, based on trends observed experimentally under (1), the theoretical predictions from (2), and the capabilities of synthetic chemistry, 4) explore changes of the electronic structure near nano-structured electrodes, and 5) explore changes of the molecular electronic structure at metallic contacts. A key challenge to photovoltaic power generation is reducing cost. The current dye-sensitized solar cell design is dominated by expensive Ru-based dyes and has reached a plateau in efficiency. The broad systematic investigation of organic dyes in this project is timely, enabling a full feedback cycle (synthesis, analysis, prediction) to optimize molecules and substrates for solar cells. The project is collaborative between Spain and US chemists, including an exchange of researchers, and postdoctoral and graduate student internships in the partner international institution. Researchers in this project are actively engaged in outreach activities leveraged with several institutional programs.