Browsing by Author "Pappenfus, Ted M."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    PBC-DFT : An Efficient Method to Calculate Energy Band Gaps of Conducting Polymers used in Solar Cells
    (2010) Schmidt, Jennifer A.; Koehn, Ryan E.; Pappenfus, Ted M.; Alia, Joseph D.
    In recent years, conducting polymers have gained attention for their promising application in solar cells due to their potential low cost, lightweight, and flexibility. Desirable polymers have a small band gap and a low HOMO energy level. Methods of finding this band gap exist using density functional theory (DFT) by calculating the energy gaps of increasing oligomer lengths (n), and plotting the HOMO-LUMO gap (in eV) as a function of the reciprocal polymer length (1/n). This method, however, proves time consuming and computationally costly. An alternative, less time-consuming method using periodic boundary conditions (PBC) exists. In our research, we studied existing donor-acceptor polymers from the literature and used PBC to calculate their band gaps for comparison with experimental data. To perform these calculations we used DFT at the B3LYP/3-21G(d) level of theory on optimized dimers. The PBC method yields results consistent with experimental values and can be useful in determining theoretical band gaps prior to synthesis which can aid in saving valuable lab time.
  • Thumbnail Image
    Item
    Renewable Energy and Sustainable Chemistry Across the Undergraduate Chemistry Curriculum
    (2010) Pappenfus, Ted M.; Carpenter, Nancy E.; Soderberg, Timothy J.; Power, Caleb; Koehn, Ryan E.; Schmidt, Jennifer
    Issues of energy and sustainability are having a direct impact on the public and are capturing the interests of many. As result, it is no surprise that science, including the field of chemistry, will become more connected with society in the future. To address this connection, we are in the process of integrating important elements of renewable energy and sustainable chemistry across the undergraduate chemistry curriculum at the University of Minnesota, Morris. This project strives to create a curriculum which is more interdisciplinary with respect to both teaching and research and which introduces topics that are timely, yet essential in preparing undergraduate students. Our initial efforts are focused on three key areas: (i) developing new courses in renewable energy and sustainability; (ii) integrating photovoltaics across the undergraduate curriculum; and (iii) illustrating the role of biochemistry in renewable energy and sustainability. Our goal is to develop a far-reaching energy and sustainable chemistry curriculum that complements the traditional curriculum and better prepares our future graduates for success in addressing global problems. An overview of the project will be presented along with our preliminary results.